Metastatic balloon cell melanoma-a rare differential in the diagnosis of clear cell tumors: Report of two cases

Two patients aged 65 and 66 years old presented with an enlarged inguinal lymph node. Clinically and radiographically, the inguinal mass was considered to be metastatic; however, first patient had no history of primary neoplasm. A fine-needle aspiration (FNA) cytologic examination of inguinal lymph node in both the cases showed numerous discohesive, pleomophic tumor cells with abundant, vacuolated cytoplasm and eccentrically placed round to ovoid nucleus with inconspicuous nucleoli and frequent intranuclear cytoplasmic pseudoinclusions. Pigment was not identified in the FNA of both the cases. Histopathological examination of the inguinal lymph node biopsy confirmed the diagnosis. These features, along with strong immunohistochemical positivity for HMB-45, suggested the diagnosis of metastatic balloon cell melanoma.