Abstract:

A 45-year-old woman presents with a tender, bleeding mass of the right thigh, noted during the past year. On examination, she had a pink firm 1 cm papule. No other concerning lesions were identified. The initial clinical differential diagnosis included neurofibroma, myofibroma, and pyogenic granuloma. A shave biopsy demonstrated a dermal proliferation of round to spindled cells, with variable myxoid stroma, negative for S100 protein, SOX10, CD34, CD31, CD68, SMA, ALK-1, CKAE1/3, and desmin. There was a notable focal dot-like Golgi WT1. Next-generation-sequencing sarcoma fusion panel confirmed the diagnosis of aggressive CIC-DUX4 rearranged sarcoma. A whole-body PET scan revealed no evidence of metastatic disease. The mass was noted to be 1.5 cm and a wide local excision with complex reconstruction was performed. At two-month follow-up, there was no evidence of disease. CIC-DUX4 sarcoma rarely occurs in the dermis and is more common in deep soft tissue skeletal muscle. CIC is a transcription factor that plays a role in regulating receptor tyrosine kinase signaling pathways and DUX4 is a transcriptional activator, both leading to oncogenesis and metastatic capability. This tumor often metastasizes to the lung, with an associated poor prognosis. Treatment options include wide local excision, Mohs micrographic surgery, adjuvant radiation, and chemotherapy. Despite aggressive current treatment, median survival is often less than two years. The outcome may be better with small, superficial (dermal) involvement.

Financial Disclosure:
No current or relevant financial relationships exist.

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Noor Kawmi, BS