Non-specific skin lesions in angioimmunoblastic T-cell lymphoma lead to diagnosis challenge: a case report and literature review.

Background: Angioimmunoblastic T-cell lymphoma (AITL), a rare and aggressive subtype of T-cell lymphoma, affects the skin in up to 50% of cases. Its protean clinical and histopathological cutaneous manifestations pose a challenge in diagnosis, particularly when skin involvement precedes lymph node biopsy confirmation. Case presentation: A 63-year-old male initially presented with progressive erythema and nodules, later developing vasculitis-like ulcers and generalized lymphadenopathy. The skin biopsy of erythema demonstrated mild perivascular lymphocytic infiltration around small blood vessels throughout the entire dermis, while the vasculitis-like ulcer biopsy demonstrated perivascular lymphocytic infiltration and small blood vessel hyperplasia. The final diagnosis of AITL was made through lymph node incisional biopsy based on morphology and immunohistochemistry. The patient received chemotherapy with the miniCHOP regimen. The skin lesions improved after treatment, and the patient remained under follow-up. Conclusion: Cutaneous manifestations of AITL are diverse, non-specific and can precede systemic symptoms. Histopathologically, cytological atypia is rarely reported. Immunohistochemistry for T-helper markers and molecular data is sometimes useful. However, both clinical manifestations and histopathology of skin lesions are often non-specific and diverse, leading to misdiagnosis and treatment delay. Continuous observation is necessary in AITL patients who develop skin lesions prior to lymphadenopathy, while the final diagnosis of AITL is still based on lymph node biopsy. Clinicians should be vigilant regarding the cutaneous manifestations of AITL to make an early and accurate diagnosis.