Synchronous rectal cancer and extranodal NK/T-cell lymphoma, nasal type: A case report.

RATIONALE: Synchronous primary malignancies involving solid tumors and aggressive lymphomas, such as extranodal NK/T-cell lymphoma, nasal type (ENKTL-NT), are exceedingly rare and pose significant diagnostic and therapeutic challenges. To our knowledge, no previously reported case of synchronous rectal adenocarcinoma and ENKTL-NT has been identified in the available literature.

PATIENT CONCERNS: A 64-year-old man presented with malaise, loss of appetite, toothache, gingival swelling, and a persistent facial sinus with purulent discharge.

DIAGNOSES: Colonoscopy and histopathological examination confirmed moderately differentiated rectal adenocarcinoma with liver and sacral bone metastases. Histopathological and immunohistochemical analysis of the facial tissue confirmed ENKTL-NT, which was positive for Epstein‑Barr virus‑encoded small RNA, CD3, CD56, and T‑cell intracellular antigen-1.

INTERVENTIONS: The patient received 2 cycles of CHOP (cyclophosphamide, hydroxydaunorubicin/doxorubicin, Oncovin/vincristine, and prednisone) chemotherapy before a definitive diagnosis was established. Owing to rapid disease progression and poor nutritional status, no further lymphoma-specific therapy was feasible.

OUTCOMES: The patient died 3 months after diagnosis, underscoring the aggressive nature of ENKTL-NT and the risks associated with empirical chemotherapy.

LESSONS: This case highlights the critical need for early and accurate histopathological diagnosis in suspected lymphoma cases and emphasizes a multidisciplinary strategy to optimize management when synchronous aggressive malignancies are present. Anthracycline-based regimens should be avoided in ENKTL-NT.