Evidence-Based Dermatology: Everyone's Business

Clinical features and treatment outcomes for primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder: a retrospective cohort study from the Dana-Farber Cancer Institute and updated literature review

Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder (PCSM-TCLPD) was reclassified in 2016 as a rare benign entity with an excellent prognosis, yet its clinical features and best treatments remain poorly defined. We collected clinical data, treatments, and treatment-responses from our institution's patients with PCSM-TCLPD through September 2018 and an identical PubMed review through June 2021. Among 36 cases (median-age 54 years; 58.3% head/neck), diagnostic biopsy resulted in sustained complete remission (CR) in 13/33 punch/shave biopsies and 3/3 excisional biopsies. The remaining 20 patients further required topical corticosteroids (n = 5); intralesional corticosteroids (n = 1); surgical-excision (n = 5); electron-beam-radiation (n = 6); or brachytherapy (n = 3). All patients ultimately achieved CR, excluding one patient continuing treatment at end-of-study. 57/59 (96.6%) of institutional and literature-reported radiation-treated patients experienced CR. No institutional cases progressed beyond skin; 5/209 (2.4%) literature-reported cases progressed to systemic/extracutaneous involvement, all pre-reclassification. PCSM-TCLPD responds well to local-directed therapy including radiation, and only rarely if ever progresses.

Diagnosis of T-cell lymphoid proliferations of the skin: putting all the pieces together

The spectrum of T-cell lymphoid proliferations of the skin varies from indolent to highly aggressive diseases and therefore an accurate pathological diagnosis is paramount. Integration of clinical, histopathological, immunohistochemical, and molecular findings is of crucial importance in the evaluation of these processes. In this article, we discuss selected situations where difficulty may arise for the pathologist evaluating this type of skin biopsies, such as: the diagnosis of early (patch stage) mycosis fungoides, the distinction of mycosis fungoides with large cell transformation from primary cutaneous anaplastic large cell lymphoma, the recognition of new histopathological patterns of lymphomatoid papulosis and the entities they mimic, the evaluation of primary cutaneous anaplastic large cell lymphoma with expression of markers suggestive of systemic origin (such as ALK), the awareness of the wide range of clinical and pathological presentations of hydroa vacciniforme-like EBV-positive T-cell lymphoproliferative disorders, the evaluation of cases of primary cutaneous γδ T-cell lymphoma showing predominantly epidermotropic pattern of growth, and the correct interpretation of findings seen in indolent proliferations such as primary cutaneous acral CD8-positive T-cell lymphoma and primary cutaneous small/medium size CD4 + T-cell lymphoproliferative disorder.

Managing Patients with Cutaneous B-Cell and T-Cell Lymphomas Other Than Mycosis Fungoides

Cutaneous lymphomas (CL) are a heterogeneous group of neoplasms characterized with clinical and histopathological variation, as well as overlap with benign dermatoses. Diagnosis and treatment of CLs is challenging and often requires a multidisciplinary approach. However, prognostic knowledge of these conditions and awareness of treatment options can help optimize appropriate use of available regimens, thereby improving care for patients. Here, we review the most recent literature and outline treatment themes for managing patients with cutaneous B-cell and T-cell lymphomas other than mycosis fungoides.

CD4 + primary cutaneous small/medium-sized pleomorphic T-cell lymphoma: a retrospective case series and review of literature

CD4 + primary cutaneous small/medium-sized pleomorphic T-cell lymphoma (CD4 + PCSM-TCL) is a rare T-cell lymphoma associated with a favorable prognosis. A retrospective study of 23 patients with CD4 + PCSM-TCL as defined by World Health Organization-European Organisation for Research and Treatment of Cancer (WHO-EORTC) and WHO classifications was conducted. Median age was 63 years. The head and neck were the most commonly affected locations, followed by the trunk. Two patients had evidence of systemic involvement at relapse. All tumors were CD3 + and CD4+. CD5 and CD7 loss occurred in 52% and 84%, respectively. The median follow-up was 33.6 months. Eleven patients had excisional biopsy only, six had localized radiotherapy and two received excision and localized radiation. Cytotoxic chemotherapy and localized radiation were used in one patient with aggressive and invasive features. All patients had a complete remission but one developed systemic involvement. Our case series demonstrates that CD4 + PCSM-TCL is an indolent T-cell lymphoma that can be treated with local modalities and raises the question of its current classification as a lymphoma.