Panniculitic primary cutaneous gamma delta T-cell lymphoma with concomitant features of autoimmune disease emphasizing a pathophysiologic continuum of lupus profundus with the panniculitic T cell lymphomas

[Cutaneous T-cell lymphomas]

Primitive cutaneous T-cell lymphomas are lymphomas clinically restricted to skin at diagnosis in opposite to skin localizations of systemic lymphomas. Cutaneous T-cell lymphomas are the most frequent. Beside mycosis fungoides and related forms, CD30+ lymphoproliferations (lymphomatoid papulosis, anaplastic large cell primitive cutaneous T-cell lymphomas) and erythrodermic T-cell lymphomas which constitute the main entities, other rare lymphomas are described: panniculitis like alpha/beta lymphoma, gamma/delta lymphoma, epidermotropic CD8+ aggressive lymphoma, small to medium T-cell lymphomas and acral CD8+ lymphoproliferations. Clinical skin examination and skin biopsy examination are crucial for diagnosis but recent advances in molecular genetics bring promising tools for diagnostic. Thanks to international cooperative groups, treatment of mycosis fungoides, CD30+ lymphoproliferations and erythrodermic lymphomas is now well established which is not the case for the other entities. Treatments may be classified in five categories: skin directed therapies, systemic non-chemotherapeutic treatments, immunomodulators, targeted immunotherapies and chemotherapies.

Subcutaneous panniculitic-like T-cell lymphoma localized to a site of peginterferon alfa-2a administration

T cell dyscrasias that demonstrate a proclivity for the subcutaneous fat include atypical lymphocytic lobular panniculitis, lupus profundus, and primary subcutaneous T cell lymphoma, including subcutaneous panniculitis-like T cell lymphoma (SPTCL). We encountered two patients who developed fever and indurated abdominal erythema at their peginterferon alfa-2a injection sites. Biopsies showed an atypical CD8 positive, granzyme positive, CD5 negative, MXA negative lymphocytic lobular panniculitis, diagnostic of SPTCL. Peginterferon alfa-2a was held in both patients. One patient received chemotherapy with an excellent response, while the other continued to have progressive disease. Peginterferon alfa-2a is known to significantly elevate serum MXA, which may induce high levels of MXA expression at the injection site, creating a microenvironment for the development of lupus profundus, which may eventuate into SPTCL. In summation, a potential risk of peginterferon alfa-2a injections is the development of SPTCL potentially arising in a background of an exogenous interferon triggered lymphocytic panniculitis.