The co‐occurrence of T‐lymphoblastic leukemia/lymphoma and thymic neoplasia is a rare event that can present a diagnostic challenge. In this case report, we describe a 31‐year‐old man who was found to have thymic neuroendocrine carcinoma and T‐lymphoblastic leukemia/lymphoma 2 years after initial treatment for T‐lymphoblastic leukemia/lymphoma. The thymic neuroendocrine carcinoma was initially detected in a malignant pleural effusion, and a retrospective review of a preceding lung biopsy suggested the involvement of both tumors within one tissue sample. Immunohistochemical analysis was imperative in highlighting these two elements because despite their unique cytomorphological characteristics, a limited amount of each component was seen in the tissue biopsy. Ancillary testing is critical to the recognition of these entities in small biopsies.
Oliveira et al. (Thu,) studied this question.