Angioimmunoblastic T-cell lymphoma mimicking diffuse large B-cell lymphoma.

Angioimmunoblastic T-cell lymphoma (AITL) is an aggressive form of peripheral T-cell lymphoma that is characterized by lymphadenopathy, night sweats, fever, weight loss, and autoimmune phenomena. Cutaneous manifestations are present in up to 50% of cases, but few cases are reported in the dermatologic literature. We present a case of AITL that manifested in the skin. The patient was diagnosed with diffuse large B-cell non-Hodgkin lymphoma 3 months prior based on results from a lymph node biopsy. Reexamination and immunohistochemical staining of the previously biopsied lymph node specimen revealed the same clonal population of T cells positive for CD3, CD4, CD10, and programmed cell death protein 1 (PD-1) that was present in the skin and confirmed a diagnosis of AITL. Angioimmunoblastic T-cell lymphoma is frequently misdiagnosed due to its nonspecific clinical and histologic findings; it is not uncommon for AITL to be mistaken for other types of lymphoma. Dermatologists and dermatopathologists can play an important role in the recognition of this difficult-to-diagnose malignancy.