Abstract
We report a 63-year-old Japanese woman who presented with an 11×9 mm dark-red nodule on the right upper part of her abdomen. The lesion had been growing for two months. Histlogical examination showed that the tumor was well circumscribed and centered almost in the dermis. Grenz zone, epithelial collarette and solar elastosis in the surrounding area were not found. The tumor consisted mainly of atypical spindle cells, showing a storiform pattern. Histiocyte-like round cells and bizarre giant cells were also recognized. Immunohistochemical findings confirmed that tumor cells were partially positive for α-SMA and lysozyme. Tumor cells did not stain for actin, myosin, desmin, or S-100. MIB1 was positive for 20% of the tumor cells. We diagnosed this case as malignant fibrous histiocytoma based upon these findings. A wide excision was performed. No recurrence has been evidenced 5 months postoperatively.[Skin Cancer (Japan) 2013 ; 28 : 320-324]
