Abstract
A 66-year-old man presented with a subcutaneous mass in the back in 2007. The mass was surgically resected and diagnosed as a metastatic tumor ; however, the primary lesion remained unknown. One year later, the tumor metastasized in the axillary and clavicular lymph nodes in addition to the back and chest subcutaneous tissue. After chemotherapy, wide resection and lymph node dissection were performed, followed by adjuvant chemotherapy together with radiotherapy in the orthopedics department of our hospital. The metastatic tumors were histopathologically S-100 protein positive, but negative for HMB-45 and MART-1, and were then diagnosed as a malignant peripheral nerve sheath tumor. In 2009, he had metastases in the adrenal glands, which were resected. Subsequently, he presented with multiple metastases in the skin and bone, and was sent to us for consultation. Since the serum level of 5-S-CD was elevated, tumors were reexamined immunohistochemically. Based on positivity for both MITF and high molecular weight-melanoma-associated antigen, we diagnosed this case as malignant melanoma.[Skin Cancer (Japan) 2010 ; 25 : 353-357]
