Systematic review of cases of cutaneous T-cell lymphoma transformation in pityriasis lichenoides and small plaque parapsoriasis

Mycosis fungoides and Sézary syndrome: clinical presentation, diagnosis, staging, and therapeutic management

Mycosis fungoides (MF) and Sézary syndrome (SS) are cutaneous T-cell lymphomas. MF is the most common cutaneous lymphoma, and it is classified into classic Alibert-Bazin MF, folliculotropic MF, pagetoid reticulosis, and granulomatous slack skin, each with characteristic clinical presentation, histopathological findings, and distinct clinical behaviors. SS is an aggressive leukemic variant of cutaneous lymphoma, and it is characterized by erythroderma, lymphadenopathy, and peripheral blood involvement by malignant cells. There is a wide range of dermatological manifestations of MF/SS, and prompt recognition is essential for early diagnosis. Skin biopsy for histopathology and immunohistochemical analysis is imperative to confirm the diagnosis of MF/SS. Histopathology may also provide information that may influence prognosis and treatment. Staging follows the TNMB system. Besides advanced stage, other factors associated with poorer prognosis are advanced age, male gender, folliculotropism in histopathology of patients with infiltrated plaques and tumors in the head and neck region, large cell transformation, and elevated lactate dehydrogenase. Treatment is divided into skin-directed therapies (topical treatments, phototherapy, radiotherapy), and systemic therapies (biological response modifiers, targeted therapies, chemotherapy). Allogeneic bone marrow transplantation and extracorporeal photopheresis are other treatment modalities used in selected cases. This review discusses the main clinical characteristics, the histopathological/immunohistochemical findings, the staging system, and the therapeutic management of MF/SS.

Pityriasis lichenoides: a clinical and pathological case series of 49 patients with an emphasis on follow-up

The classification of pityriasis lichenoides (PL) into pityriasis lichenoides et varioliformis acuta (PLEVA), PL chronica (PLC) or febrile ulceronecrotic Mucha-Habermann disease (FUMHD) mixes clinical and chronological features. In this retrospective monocentric study, we aimed to investigate the relevance of the classification in routine practice. We included 49 patients (25 women, median age 41 years). The lesions were papular in 76% of patients, necrotic in 12%, and mixed in 12%. We found three histological patterns: "classical" (65%), "lymphomatoid" (13%), and "mild" (22%). The "lymphomatoid" pattern was associated with necrotic presentation and the "mild' pattern with papular lesions (p=0.012). Among the 27 patients with follow-up, 18% had relapses and 44% a chronic form. One patient had mycosis fungoides. Neither clinical nor histological aspects were correlated with disease progression. Clinical and histological pictures reflect more the intensity of epidermal injury rather than disease course. "Pityriasis lichenoides" should be preferred to the classical PLEVA/PLC classification.

A clinician's guide to cutaneous T-cell lymphoma presenting as recalcitrant eczematous dermatitis in adults

Cutaneous T-cell lymphoma (CTCL) encompasses a group of low-grade, non-Hodgkin lymphoma, including mycosis fungoides and Sézary syndrome. Diagnosis of CTCL can be challenging given the prolonged, gradual onset and shared characteristics with many benign inflammatory skin diseases. In this case series, we describe four unique cases of patients with chronic, recalcitrant eczematous dermatitis who presented for a patch-test consultation and were ultimately diagnosed with CTCL. In particular, we highlight clinical pearls to aid in distinguishing CTCL from inflammatory dermatoses and describe the diagnostic strategy to help dermatologists arrive at the diagnosis of CTCL at earlier stages of the disease.