Abstract
An 87-year-old man noticed a nodule on his abdomen a month ago, which had been increasing in size. Computed tomography (CT) demonstrated a tumor within the subcutaneous adipose tissue which showed iso-density to the muscle, and which was 22 mm in size. When magnetic resonance imaging (MRI) was performed two months later, the tumor showed rapid growth to 34 mm in size, and infiltration to the muscle. Histopathological examination of an incisional biopsy suggested spindle cell sarcoma. Immunohistochemical examination showed the tumor cells were negative for CD34, smooth muscle actin and pan-cytokeratin. Based on these findings, synovial sarcoma was suspected, and we proceeded with molecular diagnostic analysis by FISH (fluorescence in situ hybridization) using a dual-color, break-apart SS18 probe. As a result, translocation involving the SS18 gene was detected by the split signal, and a diagnosis of synovial sarcoma was confirmed.[Skin Cancer (Japan) 2012 ; 27 : 355-360]
