Michigan State University Veterinary Diagnostic Laboratory, Lansing, MI, USA.
J Vet Diagn Invest. 2021 Sep;33(5):932-938. doi: 10.1177/10406387211025651. Epub 2021 Jul 2.
Chromatophoromas are neoplasms that develop from the dermal pigment-bearing and light-reflecting cells (chromatophores) in the skin of reptiles, fish, and amphibians. Seventeen cutaneous chromatophoromas were identified from 851 bearded dragon submissions (2%) to a private diagnostic laboratory in a 15-y period. No sex predilection was found. Ages ranged from 9 mo to 11 y. Chromatophoromas most commonly were single, raised, variably pigmented masses or pigmented scales on the trunk, and less commonly the extremities or head. Microscopically, iridophoromas, melanophoromas, mixed chromatophoromas, and nonpigmented chromatophoromas were identified. Neoplasms were often ulcerated and invaded deep into the subcutis and muscle. Most commonly, nuclear atypia was mild-to-moderate, and mitotic count was low. Six neoplasms had abundant, periodic acid-Schiff-positive, mucinous stroma. Histologic examination was often adequate to diagnose chromatophoromas in bearded dragons given that 11 of 17 had some degree of pigmentation, although it was often scant. IHC for S100 and PNL2 could be helpful to diagnose poorly pigmented neoplasms. No lymphatic invasion or metastases at the time of excision were noted in any of the cases. Follow-up data were available for 6 cases, with no reports of recurrence or neoplasia-related death. Two cases had elevated mitotic counts and nuclear pleomorphism, which has been associated with metastasis in other reports of bearded dragon chromatophoromas. In general, it appears that aggressive surgical excision is often curative, but monitoring may be warranted for cases in which tumors had high mitotic count and nuclear pleomorphism.
色素细胞瘤是一种源自爬行动物、鱼类和两栖类皮肤中具有色素和反射光线的细胞（色素细胞）的肿瘤。在 15 年的时间里，一家私人诊断实验室从 851 份鬃狮蜥提交样本中鉴定出 17 例皮肤色素细胞瘤（占 2%）。未发现性别偏好。年龄范围从 9 个月到 11 岁。色素细胞瘤最常见的是单个、隆起、色素不定的肿块或色素鳞片，位于躯干上，较少见于四肢或头部。显微镜下，鉴定出虹彩色素细胞瘤、黑素瘤、混合色素细胞瘤和无色素色素细胞瘤。肿瘤常溃疡并侵入皮下组织和肌肉深部。最常见的是核异型性为轻度至中度，有丝分裂计数低。6 个肿瘤有丰富的、过碘酸雪夫阳性、黏液样基质。鉴于 17 例中有 11 例有一定程度的色素沉着，尽管通常很少，但对鬃狮蜥进行组织学检查通常足以诊断色素细胞瘤。免疫组化 S100 和 PNL2 有助于诊断色素沉着不足的肿瘤。在所有病例中，切除时均未发现淋巴浸润或转移。有 6 例可获得随访数据，均无复发或与肿瘤相关的死亡报告。有 2 例有较高的有丝分裂计数和核多形性，这在其他关于鬃狮蜥色素细胞瘤的报道中与转移有关。总的来说，似乎积极的手术切除通常是治愈性的，但对于那些肿瘤有较高有丝分裂计数和核多形性的病例，可能需要监测。
