Challenges in the Diagnosis of Concurrent T-Lymphoblastic Leukemia/Lymphoma and Thymic Neuroendocrine Carcinoma: A Case Report.

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.