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Cutaneous lymphomas are clonal proliferations of neoplastic T or B cells, rarely natural killer cells, or plasmacytoid dendritic cells. Cutaneous lymphomas are the second most common group of extranodal lymphomas. The annual incidence is estimated to be 1 per 100,000. The updated WHO–EORTC classification for primary cutaneous lymphomas are shown in Table 21-1.
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ADULT T-CELL LEUKEMIA/LYMPHOMA ICD-10: C83/E88
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Adult T-cell leukemia/lymphoma (ATLL) is a neoplasm of CD4+/CD25+ T cells, caused by human T-cell lymphotropic virus I (HTLV-I).
Manifested by skin infiltrates, hypercalcemia, visceral involvement, lytic bone lesions, and abnormal lymphocytes on peripheral smears.
HTLV-I is a human retrovirus. Infection by the virus does not usually cause disease, which suggests that other environmental factors are involved. Immortalization of some infected CD4+ T cells, increased mitotic activity, genetic instability, and impairment of cellular immunity can all occur after infection with HTLV-I.
ATLL occurs in southwestern Japan (Kyushu), Africa, the Caribbean Islands, and the southeastern United States. Transmission is by sexual intercourse, perinatally, or by exposure to blood or blood products (same as HIV).
There are four main categories. In the relatively indolent smoldering and chronic forms, the median survival is ≥2 years. In the acute and lymphomatous forms, it ranges from only 4 to 6 months.
Symptoms include fever, weight loss, abdominal pain, diarrhea, pleural effusion, ascites, cough, and sputum. Skin lesions occur in 50% of patients with ATLL. Single to multiple confluent erythematous, violaceous papules, ±purpura; firm violaceous to brownish nodules (Figs. 21-1 and 21-2); papulosquamous lesions, large plaques, ±ulceration; trunk > face > extremities; generalized erythroderma; poikiloderma; diffuse alopecia. Lymphadenopathy (75%) sparing mediastinal lymph nodes. Hepatomegaly (50%) and splenomegaly (25%).
Patients are seropositive (ELISA, Western blot) to HTLV-I; in IV drug users, up to 30% have dual retroviral infection with both HTLV-I and HIV. WBC ranges from normal to 500,000/µL. Peripheral blood smears show polylobulated lymphocytic nuclei (“flower cells”). Dermatopathology reveals lymphomatous infiltrates composed ...