Rare T-Cell Subtypes

Gamma/Delta Phenotype in Primary Cutaneous T-cell Lymphomas and Lymphoid Proliferations: Challenges for Diagnosis and Classification

Primary cutaneous T-cell lymphomas pose a diagnostic challenge for dermatopathologists, hematopathologists, and general surgical pathologists. Recognition of gamma/delta phenotype in cutaneous T proliferations has been enhanced by the availability of antibodies against TCRgamma and delta for immunohistochemistry. Thus, reporting gamma/delta phenotype in a cutaneous T-cell lymphoid proliferation may indicate a significant change in therapy and a challenge for dermatologists and oncologists who treat these patients. Herein, we discuss primary cutaneous gamma/delta T-cell lymphoma, its differential diagnosis, and other skin lymphoid proliferations that may show gamma/delta phenotype. Awareness of the occurrence of gamma/delta phenotype in both T-cell lymphomas and benign lymphoid proliferations involving skin is crucial for a better interpretation of histopathologic findings. Integration of clinical presentation, morphology, immunoprofile, and molecular findings is key for a correct diagnosis and appropriate therapy of lesions displaying gamma/delta T-cell phenotype.

Advances in Frontline Management of Peripheral T-cell Lymphoma

Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of lymphomas that are frequently associated with a poor prognosis. For many decades, the standard-of-care has been CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone)-based therapy, but it is well-recognized that survival outcomes are unsatisfactory, especially when compared with B-cell lymphomas. Major recent advances in cancer diagnosis and management have the potential to significantly improve PTCL outcomes. These include: (1) improved diagnostic techniques that incorporate molecular genetic data to further refine diagnosis and subtyping; (2) the development of novel agents; and (3) improved monitoring modalities, such as ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography scans and circulating tumor DNA. In this review, we aim to explore these 3 advances in the context of frontline management of PTCL.

Primary cutaneous CD4-positive small/medium T-cell lymphoproliferative disorder: The first-reported Latin-American case with response to doxycycline

Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder is a provisional entity according to the last WHO-EORTC classification. The treatment of choice has not yet been defined. Local therapies have been used with variable response. Doxycycline as a main treatment option is a potential low-cost and effective alternative for this disorder.