Clinical implication of dermatopathic lymphadenopathy among Japanese: a report of 19 cases.

To clarify the clinicopathologic and immunohistochemical features of dermatopathic lymphadenopathy not associated with mycosis fungoides among Japanese, 19 patients were studied. Seventy-four percent of the patients were more than 50 years old (median; 63 years, mean 61 years). Systemic symptoms such as fever were recorded in 68% and multicentric lymphadenopathy was noted in 83% of patients. An association of autoimmune disease or positivity of autoantibodies was recorded in 6 patients. Five patients showed cutaneous hypersensitivity reactions to a drug. Histologically, in addition to the dermatopathic lymphadenopathy, numerous immunoblasts were observed in 2 cases and sheet-like proliferation of mature plasma cells in 3 cases. Various atypical or malignant lymphoproliferative disorders exhibiting immunologic abnormalities such as angioimmunoblastic T-cell lymphoma or autoimmune disease-associated lymphadenopathy frequently occur in middle-aged and elderly patients. At least some of the patients with dermatopathic lymphadenopathy should be clinicopathologically differentiated from these lymphoproliferative disorders.