Snapshot A 60-year-old patient is at his dermatologist’s office for follow-up of his eczematous dermatitis. He has tried topical steroids with no improvement. He complains of increasing itchiness. On physical exam, he has multiple confluent and well-demarcated pink patches on his buttocks and legs with some scaling. His dermatologist suspects that this may not be eczematous dermatitis but something that mimics like it. He also has prominent inguinal lymph nodes. Prior skin biopsies have been undiagnostic, but his dermatologist decides to do one more skin biopsy. This time, the biopsy reveals classic Sézary cells. Introduction CD4+ helper T-cell lymphoma of the skin Two variants of cutaneous T-cell lymphoma (CTCL) mycosis fungoides (50-70% of CTCLs) skin involvement only Sézary syndrome (1-3% of CTCLs) leukemic form of CTCL CTCL plus malignant T-cells in the blood Other less common variant adult T-cell leukemia/lymphoma (ATLL) Epidemiology Older patients (median age 55-60) More common in male patients More common in black patients etiology Associated conditions secondary malignancies Hodgkin lymphoma other non-Hodgkin lymphomas melanoma Presentation Symptoms generalized pruritus Physical exam mycosis fungoides well-demarcated, erythematous pruritic patches and plaques in non-sun-exposed areas can have telangiectasias and ulceration erythroderma (> 90% body involvement) early lesions may be confused with atopic dermatitis of psoriasis Sézary syndrome severely pruritic erythroderma with scaling alopecia lymphadenopathy hepatosplenomegaly IMAGING Imaging if leukemia suspected CT or PET-CT of whole body studies Physical exam to assess for lymphadenopathy and organomegaly Labs complete blood count with peripheral blood smear to look for Sézary cells (atypical T-cells) PCR of blood if leukemia suspected for atypical T-cells Differential Diagnosis Adult T-cell leukemia-lymphoma (ATLL) Atopic dermatitis Psoriasis Drug eruption (SJS) diagnosis Diagnosis usually made by clinical exam and history Diagnosis confirmed with skin biopsy biopsy may be inconclusive with one lesion several months with multiple biopsies may be needed to confirm diagnosis lymphocytic infiltrate with microabscesses within thickened epidermis. “buttock cells”: atypical lymphocytes with cerebriform nuclei (Sézary cells) Treatment Stage-dependent localized topical steroids topical chemotherapies topical retinoids PUVA systemic radiation therapy systemic retinoids interferon methotrexate Complications Intense pruritus Secondary cutaneous bacterial or viral infection Prognosis Stage-dependent Mycosis fungoides typically indolent slow-growing Sézary syndrome typically aggressive can be fatal