What immunostain is needed to confirm pleomorphic dermal sarcoma, also known as atypical fibroxanthoma (AFX) or pleomorphic fibroma?

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Last updated: May 1, 2025View editorial policy

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From the Research

To confirm a diagnosis of pleomorphic dermal sarcoma, a panel of immunostains including CD10, vimentin, cytokeratin markers (AE1/AE3, CK5/6), S100, SOX10, HMB-45, muscle markers (SMA, desmin, h-caldesmon), CD34, p63, p40, and Ki-67 is recommended. This comprehensive panel is necessary because pleomorphic dermal sarcoma is essentially a diagnosis of exclusion, representing a high-grade undifferentiated pleomorphic sarcoma with dermal involvement that lacks specific lineage differentiation markers 1. The use of these immunostains helps to distinguish pleomorphic dermal sarcoma from other tumors such as atypical fibroxanthoma, leiomyosarcoma, angiosarcoma, and melanoma 2.

Key Immunostains

  • CD10: often positive in pleomorphic dermal sarcoma
  • Vimentin: demonstrates mesenchymal origin
  • Cytokeratin markers (AE1/AE3, CK5/6): rule out carcinomas
  • S100, SOX10, HMB-45: exclude melanoma
  • Muscle markers (SMA, desmin, h-caldesmon): distinguish from leiomyosarcoma
  • CD34: rule out angiosarcoma
  • p63, p40: exclude atypical fibroxanthoma
  • Ki-67: assess proliferation index

Diagnosis of Exclusion

Pleomorphic dermal sarcoma is a rare cutaneous malignancy that is best managed with adequate surgical excision 3. The diagnosis is often made by excluding other possible tumors, and the use of a comprehensive panel of immunostains is essential in making an accurate diagnosis 4.

Clinical Features

Pleomorphic dermal sarcoma typically affects elderly patients and arises in sun-exposed areas, such as the scalp 1. The tumor is characterized by its aggressive behavior, with a high rate of local recurrence and metastasis 2.

Treatment

The optimal treatment for pleomorphic dermal sarcoma is uncertain, but adequate surgical excision is recommended 3. The role of radiotherapy is undefined and requires further investigation 3.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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