Pleomorphic Dermal Sarcoma: A Clinical and Histopathologic Emulator of Atypical Fibroxanthoma, but Different Biologic...

Area of Science:

• Dermatopathology
• Surgical Oncology

Background:

• Pleomorphic dermal sarcoma (PDS) and atypical fibroxanthoma (AFX) are often indistinguishable clinically and histopathologically.
• Both PDS and AFX commonly occur on sun-damaged skin of the elderly, particularly on the head and neck.

Observation:

• This case presents a rapidly growing, exophytic 4 cm tumor initially diagnosed non-specifically.
• Histopathological features include sheets of pleomorphic epithelioid and spindle cells with multinucleation and high mitotic activity, similar to AFX.

Findings:

• PDS is distinguished from AFX by larger size (>2.0 cm) and more aggressive features like subcutaneous invasion, perineural/lymphovascular invasion, and necrosis.
• Immunohistochemistry is vital for excluding other malignancies but does not differentiate PDS from AFX.
• PDS is a rare diagnosis of exclusion, requiring complete excision and thorough histopathological analysis.

Implications:

• Accurate differentiation between PDS and AFX is critical due to PDS's higher recurrence rate and metastatic potential.
• Recognizing PDS's distinct features aids in appropriate patient management and prognosis.
• Further research is needed to clarify the nomenclature and understanding of this rare entity.