Pseudolymphomatous Atypical Fibroxanthoma.

Abstract

Atypical fibroxanthoma is a rare mesenchymal skin tumor of intermediate malignancy that typically occurs on sun-damaged skin of elderly patients. Histologically, it is composed of pleomorphic cells with hyperchromatic nuclei and abundant cytoplasm, commonly arranged in a spindle cell pattern. Different histologic variants have been described during the past years. We present a case of atypical fibroxanthoma containing a dense inflammatory infiltrate, which in conjunction with the existence of immunoblast-like and Reed-Sternberg-like neoplastic cells could be misinterpreted as a lymphoid neoplasm. Immunohistochemical studies revealed strong positivity of tumor cells for CD10 and negativity for cytokeratins, p63, p40, S100, SOX10, ERG, actin, desmin, B and T-cell markers, BCL6, CD15, and CD30. The inflammatory infiltrate contained a mixed reactive T- and B-cell population with negative T-cell receptor and immunoglobulin heavy rearrangements. We discuss the differential diagnosis of this entity in which clinical, immunohistochemical, and molecular features are essential to avoid the diagnosis of a lymphoproliferative disease.

• Authors: Rubén Garcia Castro, Alex Viñolas-Cuadros, David Moyano-Bueno, Alberto Conde-Ferreiros, Esther Cardeñoso, Angel Santos-Briz
• Journal: The American Journal of dermatopathology (Am J Dermatopathol) Vol. 42 Issue 12 Pg. 972-976 (Dec 2020) ISSN: 1533-0311 [Electronic] United States
• PMID: 32769551 (Publication Type: Case Reports)

Chemical References

• Biomarkers, Tumor

Topics

• Aged, 80 and over
• Biomarkers, Tumor (analysis, genetics)
• Biopsy
• Diagnosis, Differential
• Gene Rearrangement, T-Lymphocyte
• Genes, Immunoglobulin Heavy Chain
• Genes, T-Cell Receptor
• Humans
• Immunohistochemistry
• Male
• Neoplasms, Fibrous Tissue (genetics, immunology, pathology)
• Polymerase Chain Reaction
• Predictive Value of Tests
• Pseudolymphoma (genetics, immunology, pathology)
• Skin Neoplasms (genetics, immunology, pathology)