Lymphomas are malignant hematological neoplasms characterized by the clonal proliferation of tumor lymphocytes. Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of aggressive non-Hodgkin lymphomas, often difficult to diagnose due to their morphological and morphophenotypic polymorphism. Some forms can mimic classic Hodgkin lymphoma, thus posing a significant diagnostic challenge.

We report the case of a 31-year-old woman presenting with a mediastinal mass and cervical lymphadenopathy. Histological examination revealed a nodular architecture with large Reed–Sternberg-like cells and polymorphous inflammatory background rich in eosinophils, suggestive of classical Hodgkin lymphoma, nodular sclerosis subtype. However, immunohistochemical analysis revealed a T-cell phenotype (CD3+, CD5+, CD4+), with CD30, CD15 and GATA3 expression in large atypical cells along with EBV positivity. CD 20 and AE1/AE3 were negative. The overall profile was consistent with a peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS).

By highlighting the challenges posed by Hodgkinoid morphology, this report advocates for a rigorous morpho immunophenotypic integration to avoid misdiagnoses with critical therapeutic implications.