兽研《兽医科学前沿》01 frontiersin.org 类型：病例报告 发布时间：2026年10月7日 DOI 10.3389/fvets.2026.1891605 开放获取 编辑：Gabriele Rossi，澳大利亚默多克大学 审稿：Reza Nikzad，伊朗萨里私人执业兽医；Nabaa Al-Zubaidi，伊朗沙希德·贝赫什提医科大学 *通讯作者：Laura Kästner laura.kaestner-1@vetmed.uni-giessen.de 收稿：2026年5月26日 修回：2026年9月4日 接受：2026年9月23日 发布：2026年10月7日 引用格式：Kästner L, Marchewski J and Henrich M (2026) 病例系列：犬猫浅表脂肪瘤性错构瘤是一种此前未报道的NLCS样皮肤病变。Front. Vet. Sci. 13:1891605. doi: 10.3389/fvets.2026.1891605 版权 © 2026 Kästner、Marchewski 和 Henrich。本文为开放获取文章，依据知识共享署名许可（CC BY）条款分发。在其他论坛中使用、分发和复制本文，须注明原作者及版权所有者，并按照公认学术规范引用本刊原始发表内容。不符合上述条款的使用、分发和复制均不予许可。病例系列：犬猫浅表脂肪瘤性错构瘤是一种此前未报道的NLCS样皮肤病变 Laura Kästner *、Julia Marchewski 和 Manfred Henrich 德国吉森尤斯图斯·李比希大学兽医学院兽医病理学研究所，吉森，德国 在人类中，浅表皮肤脂肪瘤性痣（NLCS）是一种罕见的良性皮肤错构瘤，其特征为真皮内出现脂肪组织聚集，且与皮下组织无任何连接。尽管NLCS是一种已被充分认识的疾病实体，但被认为是一种罕见病变，人类文献中报道有限。迄今为止，犬和猫中尚无可比病例的报道。在一年半的时间里，共检查了6例类似NLCS样病变的病例（犬5例，猫1例）。本报告中，我们将这些病例与人类疾病在宏观特征、组织病理学、性别及患畜年龄方面进行比较。所有病例的皮肤病变均由真皮内分化良好的脂肪细胞聚集构成。鉴于其与人类病变的形态学相似性，“浅表脂肪瘤性痣样病变”这一术语可能是合适的。然而，鉴于兽医学中“痣”这一术语的使用存在争议，且可能与色素性病变混淆，我们建议将该疾病实体命名为“浅表脂肪瘤性错构瘤”。关键词：病例报告，皮肤错构瘤，浅表皮肤脂肪瘤性痣，孤立性皮肤病变，兽医皮肤病理学 1 引言 在人类医学中，浅表皮肤脂肪瘤性痣（NLCS）是一种良性皮肤错构瘤，组织学特征为真皮胶原层内出现成熟异位脂肪细胞聚集（1）。它由Hoffmann和Zurhelle于1921年首次描述（2），是一种非常罕见的皮肤病。在人类病理学中，该病变可分为两种临床亚型：经典型，由多个成群结节组成（也称为Hoffmann-Zurhelle型）；以及孤立性圆顶状变异型（3）。这种皮肤畸形通常不伴有其他任何症状。然而，偶可发生溃疡、疼痛和恶臭（3）。大体上，NLCS无法与其他皮肤病变区分，因此组织病理学检查对诊断至关重要。手术切除后复发不常见（4）。在兽医学中，“痣”这一术语存在争议。为避免与人类常见的色素性病变混淆，世界卫生组织《家畜肿瘤国际组织学分类》建议使用“错构瘤”这一术语（5）。错构瘤被定义为分化良好的细胞呈局限性聚集，通常
Kästner 等，10.3389/fvets.2026.1891605，Frontiers in Veterinary Science，02，frontiersin.org。这些病变在特定区域内排列不规则，可分为若干亚型，包括表皮型、毛囊型、皮脂腺型、顶泌汗腺型及纤维附属器型（5）。尽管在家养动物中已记录了多种皮肤错构瘤和脂肪瘤性病变（如真皮脂肪瘤），但在兽医领域尚未明确描述过与人NLCS相似的、由真皮脂肪细胞排列而成的特定表现形式。本病例系列描述了犬和猫中类NLCS病变，并特别考虑了其临床表现、组织病理学以及患病动物的年龄和性别。2 病例报告 在2025年和2026年，德国吉森尤斯图斯-李比希大学兽医病理学研究所活检服务收到的标本中，鉴定出六份具有NLCS特征的組織样本（表1）。每份样本均接受了大体检查（表1），进行了组织学检查处理，随后按照标准方案切片并进行苏木精-伊红（HE）染色。2.1 组织病理学 在组织学上，所有病例均显示出相似的特征（表1）：这些病变表现为真皮内局灶性、无包膜的扩张，使覆盖其上的表皮抬高。这是由真皮内存在分化良好的脂肪细胞所致，这些细胞呈小叶状排列并被纤维间隔分隔。小血管散布于整个组织中；然而，未观察到血管分布显著增加。脂肪细胞典型地含有单个位于病变中央的透明空泡，直径范围为50至90 μm，细胞核被推移至周边。在周边区域，空泡呈 TABLE 1 提交的活检标本。病例，物种/品种，性别，年龄，解剖部位，大体外观，组织学关键发现。1，犬，拉布拉多寻回犬，雌性，5岁，腋窝，1 cm × 1 cm × 1.5 cm，切面：坚实且呈白色，真皮内分化良好的脂肪细胞，与皮下脂肪不相连，伴有轻度角化过度。2，猫，欧洲短毛猫，雄性，8岁，腹部，1 cm × 1 cm × 0.5 cm，有蒂，切面：白色且坚实，真皮内分化良好的脂肪细胞，与皮下脂肪不相连，轻度增生的皮脂腺。3，犬，伯恩山犬，雌性，3.5岁，颈部，4 cm × 2 cm × 3 cm，带1 cm × 1 cm × 1 cm蒂，切面：米色且有弹性，溃疡形成伴坏死化脓性炎症（图1），真皮内分化良好的脂肪细胞，与皮下脂肪不相连。4，犬，斑点犬，雌性，7.5岁，大腿，2 cm × 1.5 cm × 2 cm，多灶性溃疡，切面：灰色且坚实，溃疡形成伴坏死化脓性炎症，真皮内分化良好的脂肪细胞，与皮下脂肪不相连。5，犬，法国斗牛犬，雌性，已绝育，9.6岁，耳部，2 cm × 1 cm × 1 cm，有蒂，切面：白色且坚实，坏死化脓性炎症不伴溃疡形成，真皮内分化良好的脂肪细胞，与皮下脂肪不相连。6，犬，混种犬，雌性，已绝育，9.4岁，唇部，1.5 cm × 0.2 cm × 0.3 cm，切面：白色至灰色且坚实，多结节状，上皮糜烂和溃疡形成，淋巴浆细胞性皮炎，真皮内分化良好的脂肪细胞，与皮下脂肪不相连（图2）。
Kästner 等，10.3389/fvets.2026.1891605，《兽医科学前沿》，frontiersin.org。偶见较小者，直径30至50 μm。所有病变细胞密度中等，10个高倍视野（2.37 mm²）内未见核分裂象。病例1中，覆盖其上的表皮可见轻度角化过度。病例2中，脂肪细胞延伸至毛囊水平并呈外生性生长。此外，周围真皮内邻近的皮脂腺呈轻度增生。病例3、4和5显示部分真皮基质胶原呈外生性增生，其中含有大量分化良好的脂肪细胞。病例3和4中，浅表上皮缺乏附件，并呈局灶性溃疡，伴坏死性化脓性炎症（图1）。此外，病例4中可见扩张的淋巴管。病例5中未见上皮溃疡。与其他四例不同，病例6的组织学表现为多结节状外观（图2）。上皮增生，并呈不同程度的糜烂至溃疡，伴坏死性化脓性炎症及出血性结痂。部分上皮细胞呈气球样变性。浅表真皮内，大量淋巴细胞和浆细胞散布于成熟脂肪细胞之间。四例（病例3–6）中，真皮脂肪细胞与皮下脂肪细胞之间未见连续性。相反，两例（病例1、2）显示皮下脂肪组织与真皮脂肪细胞之间界限不清。病例1至3和6中，外周可见由淋巴细胞和浆细胞组成的轻度血管周围浸润。病例3中，另外可见偶见的嗜酸性粒细胞。病例4和6中，由于这些样本中周围未受累组织有限，无法评估正常组织。胶原纤维特殊染色（Goldner和Masson三色染色）显示，所有样本均被细纤维结缔组织渗透。病例1和5中可见胶原轻度增加。3 讨论 在人类医学中，浅表性皮肤脂肪瘤痣（NLCS）是一种良性皮肤错构瘤，其组织学定义为真皮胶原内存在异位成熟脂肪细胞簇（2）。然而在兽医医学中，“痣”这一术语存在争议。在世界卫生组织国际组织学 FIGURE 1 由分化良好的脂肪细胞组成、被胶原纤维分隔的有蒂肿块。上皮溃疡，伴血清细胞性结痂（空心箭头）及坏死性化脓性炎症。（苏木精-伊红染色，比例尺：2.5 mm）。插图：更高放大倍数显示分化良好的脂肪细胞（黑色箭头）邻近表皮，伴有疏松排列的胶原纤维（空心箭头）和小血管（黑色箭头）。（苏木精-伊红染色，比例尺：250 μm）。
Kästner等 10.3389/fvets.2026.1891605 《前沿兽医科学》04 frontiersin.org 《家畜肿瘤分类》中推荐使用“错构瘤”一词，以避免与人类中频繁发生的色素性病变相混淆(5)。错构瘤这一术语在兽医病理学中已获得更广泛的接受，描述的是特定区域内局限性的高分化细胞积聚，常呈不规则排列(5)。错构瘤可进一步分为若干亚型：表皮型、毛囊型、皮脂腺型、大汗腺型和纤维附属器型。本病例系列中病变的组织学特征与所列任何亚型均不相符，提示该病变实体未在现有分类中体现。尽管组织学和临床特征在很大程度上与NLCS一致，但本文所呈现病例的分布模式与人类的经典表现不同。与通常观察到的多发性病变相反，所呈现病例中以孤立型病变为主。除一例多结节病例外，这些病变以向外生长和显著的表皮突起为特征。在人类医学中，经典型发生于生命的前三十年内，而孤立型则出现于生命的第三至第六个十年之间(6)。在所呈现的病例中，这些病变见于年轻至中年动物，包括猫和犬。六例中有五例涉及犬患者，提示可能存在物种易感性；然而，需要更大队列的进一步研究来确认这一点。此外，确切的发病年龄仍不清楚，因为无法确定这些病变是突然出现还是已存在较长时间。虽然一份报告(7)中的特定2p24缺失提示先天性起源，但大多数病例中NLCS的发病机制仍不清楚，并已提出若干其他假说。Hoffmann和Zurhelle推测脂肪细胞替代了退变的胶原纤维(化生)(2)。此外，一些作者怀疑血管周围起源；即脂肪细胞来源于真皮血管的周细胞(8)。也有推测认为这些病变是异常真皮脂肪生成的结果，而非异位脂肪移位所致(9)。一项研究表明血管周围间充质祖细胞具有成脂潜能，NLCS起源于这些细胞(10)，而另一些研究则认为病因是特发性的(11)。由于仅通过组织学检查无法明确确定发病机制，需要进一步研究，包括对犬和猫病例进行免疫组织化学表征，以更好地理解这些血管和细胞改变。在人类中，NLCS经典型(多结节型)的好发部位为骨盆带、腰部、臀部和上大腿，而孤立型可发生于任何皮肤部位(1)。在本研究中，病变的分布不限于特定解剖区域，而是发生于多种皮肤部位，这与兽医医学中关于错构瘤及人类医学中关于孤立型NLCS的既定发现相一致。在人类中，2026年的一份病例系列报告称NLCS的发生以女性为主(12)。在所呈现的病例中，六只患病动物中有五只为雌性，一只为雄性。然而，由于患者数量有限，无法就性别相关易感性得出结论。此外，Palekkodan等(13)报告了大型犬，特别是拉布拉多寻回犬，对毛囊皮脂腺错构瘤的易感性。本文所呈现的五例犬病例中有三例涉及中型至大型品种犬，这与错构瘤的发生情况一致。通常不需要治疗。手术 图2 表皮内可见毛囊(空心箭头)和多灶性突出区域，显示高分化脂肪细胞增生(黑色箭头)。多灶性可见淋巴细胞和浆细胞浸润(空心箭头)于血管性间质(黑色箭头)中。(苏木精-伊红染色，比例尺：250 μm)。
Kästner等 10.3389/fvets.2026.1891605 《Frontiers in Veterinary Science》05 frontiersin.org 出于美容原因，或观察到溃疡或其他临床指征时，可能指示进行切除（14）。虽然人类复发罕见（4），但推测犬和猫可能发生类似模式；然而，前瞻性临床研究对于证实这一假设并建立明确预后数据至关重要。为明确诊断，需进行组织病理学检查。大体上，皮肤病变应与脂肪瘤、纤维脂肪瘤、纤维上皮性息肉、胶原性错构瘤、纤维附属器错构瘤、皮脂腺错构瘤、毛囊错构瘤、表皮错构瘤和汗腺错构瘤相鉴别。这些病例主要表现为外生性病变并伴有明显的表皮突出，类似于NLCS的孤立型，以纤维上皮性息肉作为主要鉴别诊断。根据世界卫生组织《家畜肿瘤国际组织学分类》，这些被描述为包含表皮和真皮成分的外生性病变（5）。然而，由于脂肪细胞并非真皮的生理性成分，其在真皮中的存在被视为异位（5）；因此，纤维上皮性息肉并不代表我们病例的正确诊断。由于我们的标本缺乏附属器结构、毛囊、汗腺或表皮细胞等必要成分，纤维附属器性、毛囊性、汗腺性或表皮性错构瘤必须从鉴别诊断中排除。虽然一份样本显示皮脂腺增生（病例2）——提示皮脂腺错构瘤——但世界卫生组织《家畜肿瘤国际组织学分类》（5）要求有过度增殖的证据，而我们的病例中未观察到这一证据。因此，这些病变可被排除。在人类医学中，关于皮赘、NLCS和脂肪纤维瘤之间的区分存在持续争论。一些作者认为，带蒂病变真皮中存在脂肪细胞是NLCS的定义性特征（15, 16）。然而，其他作者将这些病变归类为带蒂脂肪纤维瘤，尤其是当其孤立发生且位于经典骨盆分布区域之外时（17）。然而，在组织学上，作者未发现与NLCS的差异，这意味着区分往往基于临床参数，如患者年龄和病变部位（18）。我们病例的组织学表现与NLCS无法区分。然而，应避免使用“迷芽瘤”一词，因为皮下组织通常被视为皮肤的最深层（19）。经典上，NLCS的定义是真皮脂肪细胞与皮下组织之间缺乏连续性（2）。在本研究呈现的两例病例中，这一明确边界不清晰。虽然根据经典皮肤病理学标准，这种连续性的丧失可能提示替代性病理过程或将病变排除在典型NLCS分类之外，但我们遵循Patil等（1）的建议。作者指出，在真皮脂肪细胞广泛增殖过程中，边界可能变得日益模糊，此类病例仍应被视为同一病变实体的一部分（1）。由于我们两例病例中皮下脂肪与真皮增殖之间的分界不清，还必须考虑延伸至真皮的脂肪瘤。需要进一步研究以建立明确的组织学边界，并更好地界定NLCS与真皮脂肪瘤之间的区别。即使将这两例排除在分析之外，其余病例的形态学特征仍一致支持我们对病变的描述。鉴于本研究中病例与NLCS和错构瘤性病变均有重叠，“浅表脂肪瘤性错构瘤”或“类似浅表性皮肤脂肪瘤痣的病变”等术语或可作为这些病例的描述性命名，尚待进一步大规模研究验证此类分类。4 结论 本研究呈现了一系列表现出与人类浅表性皮肤脂肪瘤痣（NLCS）一致特征的皮肤病变病例。考虑到对“痣”的理解不断演变及其与错构瘤的重叠，我们的发现提示犬和猫中存在一种NLCS样病变实体，我们建议暂将其命名为“浅表脂肪瘤性错构瘤”。由于病例数量有限，本病例系列的发现应谨慎解读；对这一潜在实体的正式验证需要更大规模的研究和综合临床病理学关联。数据可用性声明 支持本文结论的原始数据将由作者提供，无不当保留。伦理声明 根据当地法规和机构要求，涉及人类的研究无需伦理批准。根据国家法规和机构要求，本研究无需参与者或其法定监护人/近亲属的书面知情同意。根据当地法规和机构要求，涉及动物的研究无需伦理批准，因为未进行实验性动物操作。该病变是在常规提交的活检材料中偶然发现的，这些材料是作为标准诊断程序的一部分采集的，并非在前瞻性动物实验框架内采集。未获得动物主人关于其动物参与本研究的书面知情同意，因为材料是作为常规诊断程序的一部分提交的。所有数据均已完全匿名化，动物及其主人都无法被识别。已获得参与者书面知情同意以发表本病例报告。作者贡献 LK：概念化、数据管理、可视化、撰写——原始草稿、撰写——审阅与编辑。JM：数据管理、撰写——审阅与编辑。MH：撰写——审阅与编辑。
Kästner 等，10.3389/fvets.2026.1891605，《Frontiers in Veterinary Science》06，frontiersin.org 资助 作者声明本研究及/或其发表未获得资金支持。利益冲突 作者声明本研究是在不存在任何可能被视为潜在利益冲突的商业或财务关系的情况下进行的。生成式人工智能声明 作者声明在手稿的创作中使用了生成式人工智能。在翻译方面，部分使用了人工智能（JLU HAWKI2 AI Chat）。作者对本工作的内容承担全部责任。人工智能的使用仅用于翻译目的，而非用于创作内容或分析数据。本文中图表旁提供的任何替代文本（alt text）均由 Frontiers 在人工智能支持下生成，并已尽合理努力确保准确性，包括在可能情况下由作者进行审核。如有任何问题，请联系我们。出版者声明 本文中表达的所有主张仅为作者的观点，不一定代表其所属机构、出版者、编辑和审稿人的观点。本文中可能评估的任何产品或其制造商可能提出的任何主张，均不受出版者保证或认可。参考文献 1. Patil SB, Narchal S, Paricharak M, More S. Nevus lipomatosus cutaneous superficialis: a rare case report. Iran J Med Sci. (2014) 39:304–7. 2. Hoffmann E, Zurhelle E. Über einen Naevus lipomatodes cutaneus superficialis der linken Glutäalgegend. Arch Dermatol Syph. (1921) 130:327–33. doi: 10.1007/BF01826150 3. Hwang HB, Yoon S, Hong KY. Nevus lipomatosus superficialis mimicking ectopic breast tissue: a rare case report. Medicine. (2025) 104:e41339. doi: 10.1097/MD.0000000000041339 4. Ranjkesh MR, Herizchi QH, Yousefi N. Nevus lipomatosus cutaneous superficialis: a case report with histologic findings. J Turk Acad Dermatol. (2009) 3:93103c. 5. Goldschmidt MH, Dunstan RW, Stannard AA, von Tscharner C, Walder EJ, Yager JA. Hamartomas. In: Goldschmidt MH, Dunstan RW, Stannard AA, Tscharner Cvon, Walder EJ and Yager JA, editors. Histological Classification of Epithelial and Melanocytic Tumors of the Skin of Domestic Animals. 2nd. Washington: Armed Forces Institute of Pathology; (1998). p. 35–36. 6. Lima CDS, Issa MCA, Souza MBD, Góes HFDO, Santos TBPD, Vilar EAG. Nevus lipomatosus cutaneous superficialis. An Bras Dermatol. (2017) 92:711–3. doi: 10.1590/abd1806-4841.20175217 7. Cardot-Leccia N, Italiano A, Monteil MC, Basc E, Perrin C, Pedeutour F. Naevus lipomatosus superficialis: a case report with a 2p24 deletion. Br J Dermatol. (2007) 156:380–1. doi: 10.1111/j.1365-2133.2006.07622.x 8. Reymond JL, Stoebner P, Amblard P. Nevus lipomatosus cutaneous superficialis: an electron microscopic study of four cases. J Cutan Pathol. (1980) 7:295–301. doi: 10.1111/j.1600-0560.1980.tb01198.x 9. Goucha S, Khaled A, Zéglaoui F, Rammeh S, Zermani R, Fazaa B. Nevus lipomatosus cutaneous superficialis: report of eight cases. Dermatol Ther. (2011) 1:25–30. doi: 10.1007/s13555-011-0006-y 10. AbdullGaffar B, Keloth T. Nevus lipomatosus superficialis: a series of six cases. J Cutan Pathol. (2024) 51:119–29. doi: 10.1111/cup.14552 11. Dotz W. Nevus lipomatosus cutaneus superficialis: a light and electron microscopic study. Arch Dermatol. (1984) 120:376–9. doi: 10.1001/archderm.1984.01650390098021 12. Mawlong AK, Agrawal A, Singh L, Sharma S. Clinicopathological spectrum of nevus lipomatosus superficialis: insights from a single-center study. Cureus. (2026) 18:e102241. doi: 10.7759/cureus.102241 13. Palekkodan H, Pradeep M, Sushma P, Kailas P, George AJ, Krishna BD, et al. Cutaneous hamartomas in dogs: epidemiology and pathology. Int J Vet Sci Anim Husband. (2025) 10:14–8. 14. Yap FB. Nevus lipomatosus superficialis. Singapore Med J. (2009) 50:e161–2. 15. Suleiman J, Suleman M, Amsi P, Minja P, Lodhia J. Giant pedunculated lipofibroma of the thigh. J Surg Case Rep. (2023) rjad153. doi: 10.1093/jscr/rjad153 16. Öztürkcan S, Terzioğlu A, Akyol M, Altinor S, Yildiz E. Pedunculated lipofibroma. J Dermatol. (2000) 27:288–90. doi: 10.1111/j.1346-8138.2000.tb02168.x 17. Nogita T, Wong TY, Hidano A, Mihm MC. Pedunculated lipofibroma: a clinicopathologic study of 32 cases supporting a simplified nomenclature. J Am Acad Dermatol. (1994) 31:235–40. 18. Adotama P, Hutson SD, Rieder EA, Stein JA, Kim RH. Revisiting solitary pedunculated lipofibromas. Am J Clin Pathol. (2021) 156:954–7. doi: 10.1093/ajcp/aqab075 19. Mohamed SA, Hargest R. Surgical anatomy of the skin. Surgery (Oxford). (2022) 40:1–7. doi: 10.1016/j.mpsur.2021.11.021
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Frontiers in Veterinary Science01frontiersin.org TYPE Case Report PUBLISHED 07 October 2026 DOI 10.3389/fvets.2026.1891605 OPEN ACCESS EDITED BY Gabriele Rossi, Murdoch University, Australia REVIEWED BY Reza Nikzad, Private Practitioner, Sari, Iran Nabaa Al-Zubaidi, Shahid Beheshti University of Medical Sciences, Iran *CORRESPONDENCE Laura Kästner laura.kaestner-1@ vetmed.uni-giessen.de RECEIVED 26 May 2026 REVISED 04 September 2026 ACCEPTED 23 September 2026 PUBLISHED 07 October 2026 CITATION Kästner L, Marchewski J and Henrich M (2026) Case series: Superficial lipomatous hamartoma in dogs and cats is a previously unreported NLCS-like dermal lesion. Front. Vet. Sci. 13:1891605. doi: 10.3389/fvets.2026.1891605 COPYRIGHT © 2026 Kästner, Marchewski and Henrich. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Case series: Superficial lipomatous hamartoma in dogs and cats is a previously unreported NLCS-like dermal lesion Laura Kästner *, Julia Marchewski and Manfred Henrich Faculty of Veterinary Medicine, Institute of Veterinary-Pathology, Justus Liebig University Giessen, Giessen, Germany In humans nevus lipomatosus cutaneous superficialis (NLCS) is a rare, benign dermal hamartoma characterized by aggregates of adipose tissue within the dermis without any connection to the subcutaneous tissue. Although NLCS is a well-recognized entity, it is considered a rare lesion with limited reports in the human literature. To date, no comparable cases have been reported in dogs and cats. Over the course of one and a half years, six cases (five in dogs, one in a cat), resembling NLCS-like lesions, were examined. In this report, we compare these cases to the human condition regarding macroscopic features, histopathology, sex, and age of the affected patients. In all cases, the dermal lesions were composed of aggregates of well-differentiated adipocytes within the dermis. Given the morphological similarity to the lesion in humans, the term “nevus lipomatosus superficialis-like lesion” might be appropriate. However, given the controversial use of the term ‘nevus’ in veterinary medicine and a potential for confusion with pigmented lesion, we propose the term “superficial lipomatous hamartoma” for this entity. KEYWORDS case report, cutaneous hamartoma, nevus lipomatosus cutaneous superficialis, solitary skin lesion, veterinary dermatopathology 1 Introduction In human medicine, nevus lipomatosus cutaneous superficialis (NLCS) is a benign cutaneous hamartoma, histologically characterized by aggregates of mature ectopic adipocytes within the dermal collagen layers (1). It was first described in 1921 by Hoffmann and Zurhelle (2) and is a very rare dermatological condition. In human pathology, the lesion can be classified into two clinical subtypes: a classical type consisting of multiple grouped nodules (also known as Hoffmann-Zurhelle) and a solitary dome-shaped variant (3). This cutaneous malformation is usually not associated with any other symptoms. However, ulceration, pain, and foul odor occasionally occur (3). Grossly, NLCS cannot be distinguished from other cutaneous lesions, making histopathological examination essential for diagnosis. After surgical removal, recurrence is uncommon (4). In veterinary medicine, the term ‘nevus’ is controversial. To avoid confusion with pigmented lesions frequently seen in humans, the WHO International Histological Classification of Tumors of Domestic Animals recommends the term ‘hamartoma’ (5). A hamartoma is defined as a localized accumulation of well-differentiated cells, often
Kästner et al. 10.3389/fvets.2026.1891605 Frontiers in Veterinary Science02frontiersin.org arranged irregularly within a specific region, and can be categorized into several subtypes, including epidermal, follicular, sebaceous, apocrine, and fibroadnexal (5). While various cutaneous hamartomas and lipomatous lesions (e.g., dermal lipomas), have been documented in domestic animals, the specific presentation of dermal adipocytes arranged in a pattern resembling the human NLCS has not been clearly described in veterinary medicine. This case series describes NLCS-like lesions in dogs and a cat, with specific consideration given to the clinical presentation, histopathology, and the age and sex of the affected animals. 2 Case reports In 2025 and 2026, six tissue samples exhibiting features of NLCS were identified among the specimens submitted to the biopsy service of the Institute of Veterinary Pathology at Justus Liebig University Giessen, Germany (Table 1). Each sample underwent a gross examination (Table 1), was processed for histologic examination, and then cut and stained with hematoxylin and eosin (HE) following standard protocols. 2.1 Histopathology Histologically, all cases showed similar features (Table 1): these lesions showed a focal, non-encapsulated expansion of the dermis, elevating the overlying epidermis. This was caused by the presence of well-differentiated adipocytes in the dermis arranged in lobules and separated by fibrous septa. Small vessels were scattered throughout the tissue; however, no significant increase in vascularity was observed. The adipocytes typically contained a single clear vacuole located in the center of the lesion, ranging in diameter from 50 to 90 μm, with peripherally displaced nuclei. In the periphery, the vacuoles were TABLE 1 Submitted biopsy specimens. CaseSpecies/ breed SexAgeAnatomic location Gross appearance Histology key findings 1Dog Labrador retriever Female5 yearsAxilla1 cm × 1 cm × 1.5 cm, cut surface: firm and white Dermal well-differentiated adipocytes, disconnected from the subcutaneous fat, with mild hyperkeratosis 2Cat European short hair Male8 yearsAbdomen1 cm × 1 cm × 0.5 cm, pedunculate, cut surface: white and firm Dermal well-differentiated adipocytes, disconnected from the subcutaneous fat, mild hyperplastic sebaceous glands 3Dog Bernese Mountain Dog Female3.5 yearsNeck4 cm × 2 cm × 3 cm with 1 cm × 1 cm × 1 cm peduncule, cut surface: beige and elastic Ulceration with necrosuppurative inflammation (Figure 1), dermal well-differentiated adipocytes, disconnected from the subcutaneous fat 4Dog Dalmatian Female7.5 yearsThigh2 cm × 1.5 cm × 2 cm, multifocally ulcerated, cut surface: grey and firm Ulceration with necrosuppurative inflammation, dermal welldifferentiated adipocytes, disconnected from the subcutaneous fat 5Dog French bulldog Female, spayed9.6 yearsEar2 cm × 1 cm × 1 cm, pedunculated, cut surface: white and firm Necrosuppurative inflammation without Ulceration, dermal welldifferentiated adipocytes, disconnected from the subcutaneous fat 6Dog Mixed breed dog Female, spayed9.4 yearsLip1.5 cm × 0.2 cm × 0.3 cm, cut surface: white to grey and firm Multinodular, Erosion and Ulceration of the epithelium, lymphoplasmacellular dermatitis, dermal welldifferentiated adipocytes, disconnected from the subcutaneous fat (Figure 2)
Kästner et al. 10.3389/fvets.2026.1891605 Frontiers in Veterinary Science03frontiersin.org occasionally smaller, ranging from 30 to 50 μm in diameter. All lesions were moderately cellular, with no mitotic figures observed in 10 highpower fields (2.37 mm 2 ). In case 1, a mild orthokeratotic hyperkeratosis was noted in the overlying epidermis. In case 2, the adipocytes extended down to the level of the hair follicles and grew exophytically. Additionally the adjacent sebaceous glands in the surrounding dermis were mildly hyperplastic. Cases 3, 4, and 5 showed an exophytic proliferation of portions of the dermal stromal collagen containing numerous well-differentiated adipocytes. In cases 3 and 4, the superficial epithelium lacked adnexa and was focally ulcerated with necrosuppurative inflammation (Figure 1). Additionally, dilated lymphatic vessels were found in case 4. In case 5, no epithelial ulceration was observed. In contrast to the other four cases, histology of case 6 demonstrated a multinodular appearance (Figure 2). The epithelium was hyperplastic and variably eroded to ulcerated, accompanied by necrosuppurative inflammation with haemorrhagic crusts. Some epithelial cells exhibited ballooning degeneration. In the superficial dermis, numerous lymphocytes and plasma cells were interspersed among mature adipocytes. In four cases (cases 3–6), no continuity was observed between the dermal adipocytes and those of the subcutis. Conversely, two cases (cases 1, 2) exhibited an indistinct margin separating subcutaneous adipose tissue from the dermal adipocytes. In cases 1 to 3 and 6, a mild perivascular infiltrate composed of lymphocytes and plasma cells was observed at the periphery. In case 3, occasional eosinophilic granulocytes were additionally identified. Assessment of normal tissue was not possible in cases 4 and 6, due to the limited amount of surrounding unaffected tissue available in these samples. Special stains for collagen fibers (Goldner and Masson’s trichrome) demonstrated that all samples were permeated by a fine fibrous connective tissue. A mild increase in collagen was found in cases 1 and 5. 3 Discussion In human medicine, nevus lipomatosus cutaneous superficialis (NLCS) is a benign cutaneous hamartoma defined histologically by the presence of clusters of ectopic mature adipocytes within the dermal collagen (2). In veterinary medicine, however, the term “nevus” is controversial. In the WHO International Histological FIGURE 1 A pedunculated mass consisting of well-differentiated adipocytes separated by collagen fibers. The epithelium is ulcerated with a serocellular crust (empty arrow heads) and necrosuppurative inflammation. (hematoxylin and eosin stain, scale bar: 2.5 mm), Insert: Higher magnification showing well differentiated adipocytes (black arrow heads) adjacent to the epidermis with loosely packed collagen fibers (empty arrows) and small vessels (black arrows). (hematoxylin and eosin stain, scale bar: 250 μm).
Kästner et al. 10.3389/fvets.2026.1891605 Frontiers in Veterinary Science04frontiersin.org Classification of Tumors of Domestic Animals, the term “hamartoma” is recommended to avoid confusion with pigmented lesions that frequently occur in humans (5). Hamartoma, a term that has gained greater acceptance in veterinary pathology, describes a localized accumulation of well-differentiated cells, often arranged irregularly, within a specific region (5). Hamartomas can be further divided into several subtypes: epidermal, follicular, sebaceous, apocrine, and fibroadnexal. The histological features of the lesions in this case series do not correspond to any of the listed subtypes, suggesting that this entity is not represented in the existing classification. Although the histological and clinical features are largely consistent with those of NLCS, the distribution pattern in the cases presented here differs from the classic presentation in humans. In contrast to the multiple lesions typically observed, solitary-type lesions predominated in the presented cases. Except for a single multinodular case, these lesions were characterized by exophytic growth and significant epidermal protrusion. In human medicine, the classic form occurs within the first three decades of life, while the solitary form appears between the third and sixth decades of life (6). In the presented cases, these lesions were observed in young to middle-aged animals, including both cats and dogs. Five of the six cases involved canine patients, suggesting a potential species predisposition; however, further investigation with a larger cohort is required to confirm this. Furthermore, the exact age of onset remains unknown, as it could not be determined whether these lesions appeared suddenly or had been present for an extended period. While a specific 2p24 deletion in one report (7) suggests a congenital origin, the pathogenesis of NLCS remains unclear for the majority of cases, and several other hypotheses have been proposed. Hoffmann and Zurhelle postulated that adipocytes replace degenerated collagen fibers (metaplasia) (2). Furthermore, some authors suspect a perivascular origin; i.e., that the adipocytes derive from pericytes of dermal blood vessels (8). It is also postulated that these lesions arise as a result of abnormal dermal adipogenesis rather than through ectopic fat displacement (9). One study suggests that perivascular mesenchymal progenitor cells possess adipogenic potential and that NLCS originates from these cells (10), while others assume that the cause is idiopathic (11). As the pathogenesis cannot be definitively determined through histological examination alone, further investigations, including immunohistochemical characterization in both canine and feline cases, are necessary to better understand these vascular and cellular alterations. In humans, predilection sites for the classical (multinodular) form of NLCS are the pelvic girdle, the lumbar region, the buttocks and the upper thigh whereas the solitary form can occur at any cutaneous site (1). In our study, the distribution of the lesions was not restricted to specific anatomical regions but occurred at various skin sites, which is consistent with established findings regarding hamartomas in veterinary medicine and solitary NLCS in human medicine. In humans, a case series from 2026 reported a female predominance in the occurrence of the NLCS (12). In the presented cases, five of the six affected animals were female, while one was male. However, due to the limited number of patients, no conclusion can be drawn regarding a sex-related predisposition. Furthermore, Palekkodan et al. (13) reported a predisposition toward folliculosebaceous hamartomas in large-breed dogs, particularly Labrador Retrievers. Three of the five canine cases presented here involved dogs of medium to large breeds, which is consistent with the occurrence of hamartomas. Treatment is generally not required. Surgical FIGURE 2 Within the epidermis, there are hair follicles (empty arrow) and multifocal protruding areas showing a proliferation of well-differentiated adipocytes (black arrow head). Multifocally, there is an infiltration of lymphocytes and plasma cells (empty arrow heads) in a vascular stroma (black arrows). (hematoxylin and eosin stain, scale bar: 250 μm).
Kästner et al. 10.3389/fvets.2026.1891605 Frontiers in Veterinary Science05frontiersin.org removal may be indicated for cosmetic reasons or if ulceration or other clinical indications are observed (14). While recurrences are rare in humans (4), it is hypothesized that a similar pattern may occur in dogs and cats; however, prospective clinical studies are essential to confirm this assumption and to establish definitive prognostic data. For a definitive diagnosis, a histopathological examination is necessary. Grossly, the skin lesions should be differentiated from lipoma, fibrolipoma, fibroepithelial polyp, collagenous hamartoma, fibroadnexal hamartoma, sebaceous hamartoma, follicular hamartoma, epidermal hamartoma and sweat gland hamartoma. Presenting primarily as exophytic lesions with marked epidermal protrusion, these cases resemble the solitary form of NLCS, with fibroepithelial polyps as the primary differential diagnosis. According to the World Health Organization International Histological Classification of Tumors of Domestic Animals, these are described as exophytic lesions containing components of both the epidermis and dermis (5). However, as adipocytes are not physiological constituents of the dermis, their presence there is considered ectopic (5); consequently, fibroepithelial polyps do not represent a correct diagnosis for our cases. Because our specimens lacked essential components such as adnexal structures, hair follicles, sweat glands or epidermal cells, fibroadnexal, follicular, sweat gland or epidermal hamartomas must be excluded from the differential diagnosis. While one sample showed sebaceous gland hyperplasia (Case 2)-suggesting a sebaceous gland hamartoma-the WHO International Histological Classification of Tumors of Domestic Animals (5) requires evidence of excessive proliferation, which was not observed in our case. Therefore, these entities can be ruled out. In human medicine, there is an ongoing debate regarding the distinction between skin tags, NLCS, and lipofibromas. Some authors consider the presence of adipocytes in the dermis of pedunculated lesions to be a defining characteristic of NLCS (15, 16). Others, however, classify these lesions as pedunculated lipofibromas, particularly when they are solitary and occur outside the classic pelvic distribution (17). Histologically, however, the authors saw no differences from NLCS, meaning the distinction was often based on clinical parameters such as patient’s age and location of the lesion (18). The histological presentation in our cases was indistinguishable from NLCS. The term ‘choristoma’, however, should be avoided, as the subcutis is often regarded as the deepest layer of the skin (19). Classically, NLCS is defined by a lack of continuity between the dermal adipocytes and the subcutis (2). In two of the cases presented in this study, this distinct boundary was indistinct. While such a loss of continuity might, according to classic dermatopathological criteria, suggest an alternative pathological process or exclude the lesions from a typical NLCS classification, we follow the suggestion of Patil et al. (1). The authors state that the boundary can become increasingly obscured during extensive proliferation of dermal adipocytes, and such cases should nevertheless be considered part of the same entity (1). Due to the indistinct demarcation between subcutaneous fat and dermal proliferation in two of our cases, a lipoma extending into the dermis must also be considered. Further studies are required to establish clear histological boundaries and to better define the distinction between NLCS and dermal lipomas. Even if these two cases were excluded from the analysis, the morphologic characteristics of the remaining cases consistently support our proposed description of the lesion. Given the overlap of the cases in this study with both NLCS and hamartomatous lesions, the terms ‘superficial lipomatous hamartoma’ or ‘nevus lipomatosus cutaneous superficialis-like lesion’ could potentially serve as descriptive nomenclature for these cases, pending further large-scale studies to validate such a classification. 4 Conclusion This study presents a series of cases of skin lesions exhibiting features consistent with nevus lipomatosus cutaneous superficialis (NLCS) in humans. Considering the evolving understanding of ‘nevus’ and its overlap with hamartomas, our findings suggest the existence of an NLCS-like entity in dogs and cats, which we propose to be provisionally termed ‘superficial lipomatous hamartoma’. Due to the limited number of cases, the findings of this case series should be interpreted with caution; formal validation of this potential entity requires largerscale studies and integrated clinicopathological correlations. Data availability statement The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation. Ethics statement Ethical approval was not required for the study involving humans in accordance with the local legislation and institutional requirements. Written informed consent to participate in this study was not required from the participants or the participants’ legal guardians/next of kin in accordance with the national legislation and the institutional requirements. Ethical approval was not required for the studies involving animals in accordance with the local legislation and institutional requirements because no experimental animal procedures were performed. The lesion was identified incidentally in routinely submitted biopsy material that had been collected as part of standard diagnostic procedures and not within the framework of a prospective animal experiment. Written informed consent was not obtained from the owners for the participation of their animals in this study because The material was submitted as part of routine diagnostic procedures. All data were fully anonymized, and neither the animals nor their owners were identifiable. Written informed consent was obtained from the participant(s) for the publication of this case report. Author contributions LK: Conceptualization, Data curation, Visualization, Writing – original draft, Writing – review & editing. JM: Data curation, Writing – review & editing. MH: Writing – review & editing.
Kästner et al. 10.3389/fvets.2026.1891605 Frontiers in Veterinary Science06frontiersin.org Funding The author(s) declared that financial support was not received for this work and/or its publication. Conflict of interest The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Generative AI statement The author(s) declared that Generative AI was used in the creation of this manuscript. For the translation, artificial intelligence (JLU HAWKI2 AI Chat) was partially used. The authors assume full responsibility for the content of this work. The use of AI was solely for translation purposes and not for creating the content or analysing the data. Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us. Publisher’s note All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher. References 1. Patil SB, Narchal S, Paricharak M, More S. Nevus lipomatosus cutaneous superficialis: a rare case report. Iran J Med Sci. (2014) 39:304–7. 2. Hoffmann E, Zurhelle E. Über einen Naevus lipomatodes cutaneus superficialis der linken Glutäalgegend. Arch Dermatol Syph. (1921) 130:327–33. doi: 10.1007/BF01826150 3. Hwang HB, Yoon S, Hong KY. Nevus lipomatosus superficialis mimicking ectopic breast tissue: a rare case report. Medicine. (2025) 104:e41339. doi: 10.1097/MD.0000000000041339 4. Ranjkesh MR, Herizchi QH, Yousefi N. Nevus lipomatosus cutaneous superficialis: a case report with histologic findings. J Turk Acad Dermatol. (2009) 3:93103c. 5. Goldschmidt MH, Dunstan RW, Stannard AA, von Tscharner C, Walder EJ, Yager JA. Hamartomas. In: Goldschmidt MH, Dunstan RW, Stannard AA, Tscharner Cvon, Walder EJ and Yager JA, editors. Histological Classification of Epithelial and Melanocytic Tumors of the Skin of Domestic Animals. 2nd. Washington: Armed Forces Institute of Pathology; (1998). p. 35–36. 6. Lima CDS, Issa MCA, Souza MBD, Góes HFDO, Santos TBPD, Vilar EAG. Nevus lipomatosus cutaneous superficialis. An Bras Dermatol. (2017) 92:711–3. doi: 10.1590/ abd1806-4841.20175217 7. Cardot-Leccia N, Italiano A, Monteil MC, Basc E, Perrin C, Pedeutour F. Naevus lipomatosus superficialis: a case report with a 2p24 deletion. Br J Dermatol. (2007) 156:380–1. doi: 10.1111/j.1365-2133.2006.07622.x 8. Reymond JL, Stoebner P, Amblard P. Nevus lipomatosus cutaneous superficialis: an electron microscopic study of four cases. J Cutan Pathol. (1980) 7:295–301. doi: 10.1111/ j.1600-0560.1980.tb01198.x 9. Goucha S, Khaled A, Zéglaoui F, Rammeh S, Zermani R, Fazaa B. Nevus lipomatosus cutaneous superficialis: report of eight cases. Dermatol Ther. (2011) 1:25–30. doi: 10.1007/ s13555-011-0006-y 10. AbdullGaffar B, Keloth T. Nevus lipomatosus superficialis: a series of six cases. J Cutan Pathol. (2024) 51:119–29. doi: 10.1111/cup.14552 11. Dotz W. Nevus lipomatosus cutaneus superficialis: a light and electron microscopic study. Arch Dermatol. (1984) 120:376–9. doi: 10.1001/archderm.1984. 01650390098021 12. Mawlong AK, Agrawal A, Singh L, Sharma S. Clinicopathological spectrum of nevus lipomatosus superficialis: insights from a single-center study. Cureus. (2026) 18:e102241. doi: 10.7759/cureus.102241 13. Palekkodan H, Pradeep M, Sushma P, Kailas P, George AJ, Krishna BD, et al. Cutaneous hamartomas in dogs: epidemiology and pathology. Int J Vet Sci Anim Husband. (2025) 10:14–8. 14. Yap FB. Nevus lipomatosus superficialis. Singapore Med J. (2009) 50:e161–2. 15. Suleiman J, Suleman M, Amsi P, Minja P, Lodhia J. Giant pedunculated lipofibroma of the thigh. J Surg Case Rep. (2023) rjad153. doi: 10.1093/jscr/rjad153 16. Öztürkcan S, Terzioğlu A, Akyol M, Altinor S, Yildiz E. Pedunculated lipofibroma. J Dermatol. (2000) 27:288–90. doi: 10.1111/j.1346-8138.2000.tb02168.x 17. Nogita T, Wong TY, Hidano A, Mihm MC. Pedunculated lipofibroma: a clinicopathologic study of 32 cases supporting a simplified nomenclature. J Am Acad Dermatol. (1994) 31:235–40. 18. Adotama P, Hutson SD, Rieder EA, Stein JA, Kim RH. Revisiting solitary pedunculated lipofibromas. Am J Clin Pathol. (2021) 156:954–7. doi: 10.1093/ajcp/aqab075 19. Mohamed SA, Hargest R. Surgical anatomy of the skin. Surgery (Oxford). (2022) 40:1–7. doi: 10.1016/j.mpsur.2021.11.021