How to Cite
Abstract
Pleomorphic dermal sarcoma (PDS) and atypical fibroxanthoma (AFX) are rare mesenchymal tumors that share similar clinical, histological, and immunohistochemical characteristics.
Here, we present the case of an 86 year-old male with biopsy-suspected AFX who was referred to Mohs for tumor excision. On the day of surgery, physical examination showed a 2 x 2 cm friable plaque on the right crown, with no regional lymphadenopathy appreciated. During stage 2 of Mohs surgery, atypical, spindled cells were noted infiltrating the dermis and subcutaneous fat, suggesting PDS over AFX. In one tissue section of the block, a solitary vessel with intravascular involvement of the atypical cells was observed. This finding was detected using horizontal “en face” tissue processing. The Mohs slide with intravascular invasion was sent in for re-review with the regional expert in dermatopathology, confirming the final diagnosis of PDS with intravascular involvement. The tumor was successfully cleared in four stages of Mohs. The final defect (3 x 3 cm) was closed with partial intermediate layered closure and second intent wound healing.
Immunohistochemistry revealed strong and diffuse positivity for CD10 and CD68, while SOX10, S100, CD31, CD34, Desmin, and SMA were negative, further confirming the diagnosis. CT scans of the head, neck, and chest with contrast revealed no evidence of metastases. The patient was offered adjuvant radiotherapy to reduce the risk of local recurrence. The patient declined radiation and is currently being managed with three-month follow-ups and scouting biopsies without evidence of local recurrence or metastases.