Multiple subcutaneous nodules as the primary presentation of angioimmunoblastic T-cell lymphoma: a case report and literature review.

Angioimmunoblastic T-cell lymphoma (AITL) frequently involves the skin, typically presenting as rash or pruritus. However, AITL presenting primarily with multiple subcutaneous nodules is exceedingly rare and poses significant diagnostic challenges, often leading to misdiagnosis. We reported a 53-year-old man who presented with widespread subcutaneous nodules. He had a 1-month history of multiple painless subcutaneous nodules on the trunk and upper limbs. Physical examination revealed multiple firm nodules measuring 0.5-2 cm, accompanied by dark red plaques. Laboratory investigations showed mild anemia, elevated inflammatory markers, decreased IgA levels, and increased IgE levels. Imaging findings demonstrated generalized lymphadenopathy. Histopathological examination revealed effacement of the lymph node architecture with atypical lymphoid cells; immunohistochemistry was positive for CD3, CD4, PD-1, and EBER. A diagnosis of AITL of stage III was established. The patient achieved complete remission (CR) after 6 cycles of chidamide plus CHOP chemotherapy, with no evidence of recurrence at 6 months. This case broadens the recognized cutaneous spectrum of AITL and underscores the importance of considering lymphoma in the differential diagnosis of unexplained subcutaneous nodules.