Gulati Harveen Kaur, Joshi Avinash R, Anand Mani, Deshmukh S D
Department of Pathology, Smt. Kashibai Navale Medical College and General Hospital, Narhe, Pune, Maharashtra, India.
Asian J Neurosurg. 2016 Jul-Sep;11(3):317-8. doi: 10.4103/1793-5482.148789.
Melanocytic schwannoma (MS) is an extremely rare soft tissue tumor accounting for less than 1% of all primitive nerve sheath tumors, with a predilection for spinal nerve involvement. To date, only 20 cases of cutaneous/subcutaneous MS have been described in literature. Here, we describe a case of MS presenting as a subcutaneous nodule in a 22-year-old male in right thigh. On examination, the nodule measured 2.5 × 2.0 × 1.5 cm with overlying skin showing a bluish hue and an ulcer. With a preoperative diagnosis of hemangioma, the patient was taken up for wide local excision and was diagnosed as a case of non psammomatous melanocytic schwannoma based on clinical, histological, and immunohistochemical studies. Immunohistochemistry revealed positivity with S-100, HMB-45, and Melan A with pericellular Laminin positivity. Carney's syndrome was ruled out. MS needs to be differentiated from other pigmented lesions like pigmented neurofibroma, Bednar tumor, cellular blue neavus, and especially malignant melanoma, which has an obvious ominous prognosis. Since MS can show unpredictable behavior especially in absence of overt malignant features, a long term follow up with or without radiotherapy is recommended.
黑素细胞性神经鞘瘤（MS）是一种极为罕见的软组织肿瘤，占所有原始神经鞘瘤的比例不到1%，好发于累及脊神经。迄今为止，文献中仅描述了20例皮肤/皮下MS病例。在此，我们报告一例22岁男性右大腿皮下结节的MS病例。检查发现，该结节大小为2.5×2.0×1.5 cm，其上覆盖皮肤呈蓝色且有溃疡。术前诊断为血管瘤，患者接受了广泛局部切除，根据临床、组织学和免疫组化研究，诊断为非砂粒体性黑素细胞性神经鞘瘤。免疫组化显示S-100、HMB-45和Melan A呈阳性，细胞周围层粘连蛋白也呈阳性。排除了卡尼综合征。MS需要与其他色素性病变相鉴别，如色素性神经纤维瘤、贝德纳瘤、细胞性蓝色痣，尤其是恶性黑色素瘤，后者预后明显不良。由于MS可能表现出不可预测的行为，尤其是在没有明显恶性特征的情况下，建议进行长期随访，无论是否进行放疗。
