Pleomorphic Dermal Sarcoma

**Semantic type:** Neoplastic Process

**Definition:** A rare undifferentiated sarcoma with overlapping features of atypical fibroxanthoma. It occurs in severely sun-damaged skin of elderly patients and usually affects the head and neck region. It manifests with rapidly growing nodules and plaques. Morphologically, it is characterized by dermal proliferation of pleomorphic spindle cells. Epithelioid and multinucleated giant cells may by present. The tumor grows in a fascicular or storiform pattern and invades subcutaneous adipose tissue, skeletal muscle, and fascia. Tumor cell necrosis, perineural invasion, and lymphatic invasion may also be seen. There is increased mitotic activity with atypical mitoses present. Local recurrences occur in 20-30% of cases and metastases in 10-20% of cases.

**Synonyms:** - Cutaneous Malignant Fibrous Histiocytoma - Cutaneous Unclassified Pleomorphic Sarcoma - Cutaneous Unclassified Pleomorphic Sarcoma (Formerly Cutaneous "MFH") - Cutaneous Unclassified Pleomorphic Sarcoma (Formerly Cutaneous "Malignant Fibrous Histiocytoma") - Cutaneous Undifferentiated Pleomorphic Sarcoma - Malignant Cutaneous Fibrous Histiocytoma - Malignant Fibrous Histiocytoma of Skin - Malignant Fibrous Histiocytoma of the Skin - Malignant Skin Fibrous Histiocytoma - PDS - Skin Undifferentiated Pleomorphic Sarcoma