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89 year old woman presented in 1/2017 with a lesion on scalp. Biopsy from 12/30/16 first showed squamous cell carcinoma but a second opinion revealed atypical fibroxanthoma. Mohs and reconstruction performed on 1/23/2017, with the core specimen sent for additional analysis which revealed undifferentiated pleomorphic sarcoma.


This 89-year-old woman presented with an exophytic growing scalp nodule that initially was biopsied as squamous cell carcinoma; however, a second histologic opinion confirmed this to be an atypical fibroxanthoma. Due to the size of this lesion of 2.5 cm in diameter, decision was made to undergo Mohs excision with immediate reconstruction. Because of the size of this particular lesion and its significant progressive growth, the core specimen was excised, not used for Mohs processing, and instead sent for histologic analysis in formalin. Evaluation of core specimen with permanent histology is done routinely in our center when additional oncologic considerations are present. In this patient’s case, the size of this lesion and its speed of growth were atypical for a an atypical fibroxanthoma (AFX).

The histologic analysis revealed this to be an undifferentiated pleomorphic sarcoma of the scalp. The patient was presented at the Scar’s Foundation Conference to discuss additional treatment options.

Undifferentiated pleomorphic sarcoma and atypical fibroxanthoma represent a spectrum of spindle cell tumors. The two are differentiated by their behavior and the depth of invasion. The atypical fibroxanthomas (AFX) are found to be more superficial and smaller, not much larger than 1 cm. The diagnosis of pleomorphic sarcoma was made based on the more aggressive behavior and histologic findings.

The treatments of these two lesions are quite different. AFX could be treated with simple excision, Mohs excision, or occasionally with curettage and desiccation (C&D). In this particular patient despite the diagnosis of an AFX, the aggressive behavior of this tumor suggested a more aggressive approach. As a result, a 10 mm margin was taken around the tumor as a Mohs margin to ensure clearance. The patient was reconstructed at the same time with rotation flaps of the scalp. The undifferentiated pleomorphic sarcoma has a risk of dermal metastases and possibly even lymphatic metastases. In this particular patient, even wider margin treatment is required for cure. Additional 4 cm margin was recommended for radiation treatment.