2025 Volume 40 Issue 1 Pages 23-28
An 85－year－old man presented with a 20×20－mm dome－shaped, erythematous nodule on the right cheek that was mobile over the underlying tissue. Ultrasonography showed that the lesion was in contact with the subcutaneous fat but confined to the dermis. Biopsy revealed proliferation of CD10－positive spindle－shaped cells forming a nodule. A definitive diagnosis was not made, and the lesion was excised with a 3－mm margin into the mid－adipose tissue for further evaluation. The absence of deep infiltration suggested atypical fibroxanthoma. However, 5 weeks postoperatively, local recurrence with metastasis to the right cervical lymph node was observed. The patient underwent a repeat resection, along with cervical lymph node dissection and adjuvant radiotherapy. Pathological examination revealed atypical spindle cells infiltration of subcutaneous fat. During radiotherapy, metastases first appeared in the right parotid gland, followed by multiple lung and liver metastases. The patient died 1.5 months after radiotherapy. Given the rapid clinical progression and histopathological changes, we concluded that the lesion had progressed from atypical fibroxanthoma to pleomorphic dermal sarcoma. [Skin Cancer (Japan) 2025 ; 40 : 23－28]
