Subcutaneous panniculitis-like T-cell lymphoma.

Area of Science:

• Dermatology
• Hematology
• Oncology

Background:

• Subcutaneous panniculitis like T-cell lymphoma derived from α/β T-cells (SPTCL-AB) is a rare primary cutaneous T-cell lymphoma, accounting for <1% of cases.
• It predominantly affects women in their fourth decade and can be complicated by hemophagocytic syndrome, impacting survival.
• Histopathologically, SPTCL-AB presents as a lobular lymphocytic panniculitis with characteristic tumor cell distribution.

Purpose of the Study:

• To review histopathologic, immunophenotypic, and molecular data for diagnosing SPTCL-AB.
• To differentiate SPTCL-AB from other T-cell/NK/T-cell lymphomas and benign panniculitides.
• To provide a comprehensive guide for accurate identification of SPTCL-AB.

Main Methods:

• Analysis of histopathologic features, including lobular lymphocytic panniculitis and tumor cell morphology.
• Immunophenotypic characterization using markers such as CD45RO, βF1, CD3, CD4, CD8, TIA-1, granzyme, and perforin.
• Molecular analysis including TCR gene rearrangement and EBV integration assessment.

Main Results:

• SPTCL-AB exhibits a distinct lobular lymphocytic panniculitis pattern with rim and capping images.
• Tumor cells are typically CD45RO+, βF1+, CD3+, CD4-, CD8+, expressing cytotoxic granules and variable deletion of T-cell antigens.
• Most cases show monoclonal TCR gene rearrangement and lack EBV integration.

Conclusions:

• Accurate diagnosis of SPTCL-AB relies on a combination of histopathologic, immunophenotypic, and molecular findings.
• Distinguishing SPTCL-AB from other conditions with similar patterns is crucial for appropriate patient management.
• This review synthesizes key diagnostic features to aid clinicians and pathologists in identifying SPTCL-AB.