11 巻 (1996) 1 号 p. 132-136
We present here a subcutaneous tumor in a 23-year-old female that had a 5 months history of agressively enlarging subcutaneous nodule of the scalp with histologic features of malignant rhabdoid tumor (MRT) . Histologically, the tumor consisted of varying cellularity, and mainly composed of cords of cells with deeply eosinophilic cytoplasm, clear cells reminiscent of clear cell sarcoma, solidly sheets somewhat reminiscent of primitive neuroectodermal tumor, discohesive eosinophilic cells of having features of the MRT and the aggregation of spindle cells containing peripheral nerve-like organoid structures in a small area. Immunohistochemistry revealed the presence of neuron specific enolase, S-100 protein and vimenin within the tumor cells. A few spindel or dendritic cells were stained positively for anti-keratin. The p53 supressor gene protein was also positive, especially in the rhabdoid cells. We speculat-ed the tumor cells in this case revealed the neuroectodermal associated differentiaion, mainly differentiated towards the schwann cell. We concluded that the histological diagnosis was epithelioid malignant schwannoma with rhabdoid features. She was alive and well 7 months with no evidence of disease.