Concomitant Secondary Peripheral T-cell Lymphoma with Therapy-related Chronic Myelomonocytic Leukemia in a Patient with History of High-grade Follicular Lymphoma

A secondary myeloid or lymphoid neoplasm is not infrequently associated with a primary tumor, solid or hematopoietic, post cytotoxic treatment or radiation. Concurrent secondary neoplasms derived from distinct myeloid and lymphoid cell origins are rare. It is not only a diagnostic challenge, but makes for difficult treatment management. We report a very rare occurrence in 63-year-old male with a history of high-grade follicular lymphoma who was treated with multiple courses of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (RCHOP) and then developed a concurrent secondary peripheral T-cell lymphoma, not otherwise specified (sPTCL, NOS) and therapy-related myeloid neoplasm (tMN), under an umbrella of myelodysplastic/myeloproliferative neoplasm, namely chronic myelomonocytic leukemia (CMML). Despite aggressive therapeutic management, the patient passed away secondary to disease progression, complications of infection, and multi-organ failure. An appropriate diagnostic approach for complicated cases as described aided in providing the correct diagnosis.