The patient was a 73-year-old man diagnosed with low-grade B-cell lymphoma not otherwise specified based on a biopsy of the enlarged cervical lymph nodes. He remained untreated and was monitored during follow-up visits only. Progressive anemia developed after 5 years. Enteroscopy revealed stricture and ulcerative lesions involving the entire circumference of the middle section of the small intestine. Based on the biopsy results, he was diagnosed with enteropathy-associated T-cell lymphoma (EATL). Biopsy of an enlarged axillary lymph node simultaneously revealed Epstein-Barr virus-negative diffuse large B-cell lymphoma (DLBCL) and peripheral T-cell lymphoma not otherwise specified (PTCL, NOS) as well as rearrangement of immunoglobulin heavy-chain and T-cell receptor beta and gamma chain genes. These findings suggested that the axillary lymph node contained composite lymphoma comprising DLBCL and PTCL and that EATL represented a discordant lymphoma. The present case emphasizes the importance of re-biopsy and genetic analysis following an atypical clinical course.
Keywords: Composite lymphoma; Diffuse large B-cell lymphoma; Discordant lymphoma; Enteropathy-associated T-cell lymphoma.