Subcutaneous Panniculitis-like T-Cell Lymphoma: Redefinition of Diagnostic Criteria in the Recent World Health Organization–European Organization for Research and Treatment of Cancer Classification for Cutaneous Lymphomas

Abstract

Subcutaneous panniculitis-like T-cell lymphoma is a primary T-cell lymphoma that preferentially involves the subcutaneous tissue. Although subcutaneous panniculitis-like T-cell lymphoma has been recognized as a distinctive entity in the category of peripheral T-cell lymphoma in the World Health Organization classification, its diagnostic criteria has been redefined by the recent World Health Organization–European Organization for Research and Treatment of Cancer classification for primary cutaneous lymphomas. Subcutaneous panniculitis-like T-cell lymphoma is now restricted to primary cutaneous T-cell lymphoma expressing αβ T-cell receptor phenotype. These lymphomas are usually CD3+, CD4−, CD8+, and CD56−, and usually have an indolent clinical course. The clinicopathologic features, differential diagnosis, immunophenotypic characteristics, and molecular features of subcutaneous panniculitis-like T-cell lymphoma are presented in light of the recent World Health Organization–European Organization for Research and Treatment of Cancer classification.

Subcutaneous panniculitis-like T-cell lymphoma responsive to combination therapy with methotrexate and corticosteroids

“…WHO-EORTC classification now separates SPTCL from the histologic mimic, primary -cell lymphoma (TCL), based on the T-cell receptor expressed and the clinical course. Although SPTCL is limited to the subcutis and often epidermis and frequently has a more aggressive clinical course [1,2].…”

“…SPTCL can affect all ages, though classically presents in younger adults with approximately 20% of affected individuals under the age of 20 [1]. Sexes are affected equally.…”

“…Hemophagocytic lymphohistiocytosis often presents with fever, hepatosplenomegaly, rashes, cytopenias, and elevated ferritin and progresses to multi-organ failure [3]. Hemophagocytic lymphohistiocytosis is has high associated mortality [1].…”

“…Immunohistochemical analysis is required to confirm the diagnosis. T--/CD8+/CD56-and express several cytotoxic proteins such as granzyme A, perforin, and TIA-1 [1]. T-cell receptor gene rearrangement PCR studies to assess for clonality may be helpful, with clonality being universal in SPTCL and rare in LEP [5].…”

“…Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare form of non-Hodgkin lymphoma further categorized as a subtype of primary cutaneous T-cell lymphoma (CTCL). Subcutaneous panniculitis-like T-cell lymphoma accounts for less than 1% of all CTCL cases [1]. Subcutaneous panniculitis-like T-cell lymphoma can be challenging to diagnose as it may mimic other CTCL subtypes or forms of panniculitis.…”