Ultrastructure in resolving a diagnosis of poorly differentiated clear cell sarcoma of soft parts in an adolescent male.

ABSTRACT

Clear cell sarcoma of soft parts is a rare tumor in children and it requires a high index of suspicion for accurate diagnosis. Early diagnosis leads to radical surgical excision and limits the aggressive behavior of this tumor. We report a case of a 12-year-old boy with a recurrent soft-tissue tumor in the scalp, misdiagnosed on three occasions as epitheloid sarcoma owing to the poorly differentiated appearance of cells. In spite of focal S-100 expression, this tumor was not recognized as a tumor of melanocytic origin till melanosomes were demonstrated on electron microscopy (EM). Detection of melanosomes on electron microscopy helped in clinching the histology diagnosis, reiterating the definite role of EM in diagnosing these tumors. Failure to accurately diagnose this tumor resulted in institution of preoperative chemotherapy, delayed surgical excision, tumor progression and death of patient within a year and half of presentation.