A Case of Angioimmunoblastic T-Cell Lymphoma Misdiagnosed as Eczema-Like Dermatitis in an Elderly Patient.

Angioimmunoblastic T-cell lymphoma (AITL) is a clinically heterogeneous subtype of peripheral T-cell lymphoma that frequently presents with nonspecific cutaneous manifestations. Approximately 40%-50% of patients initially develop diffuse erythema or papular eruptions that may mimic benign inflammatory or allergic dermatoses, posing a diagnostic challenge in early disease stages. We report the case of an 81-year-old man who presented with generalized pruritic papules and was initially diagnosed with an eczema-like inflammatory dermatitis. Although the skin lesions showed transient improvement with symptomatic treatment, they recurred repeatedly. The subsequent onset of chills and cervical lymphadenopathy prompted further evaluation, including skin and lymph node biopsies, which established the diagnosis of AITL. Bone marrow involvement was identified by morphologic examination and flow cytometry. Immunohistochemical analysis demonstrated neoplastic T cells expressing CD3, CD4, and CD5, along with follicular helper T-cell-associated markers including CD10, BCL-6, PD-1, and CXCL13, with a Ki-67 proliferation index of approximately 70%. This case underscores the diagnostic complexity of AITL presenting with predominant allergic-like skin lesions and highlights the importance of considering underlying lymphoproliferative disorders in elderly patients with persistent, recurrent, or atypical dermatoses. Timely histopathological and immunophenotypic evaluation is essential for accurate diagnosis and appropriate management.