Synchronous primary pulmonary extranodal NK/T-cell lymphoma and relapsed Hodgkin lymphoma occurring after chemotherapy for primary Hodgkin lymphoma: A case report and literature review

Extranodal natural killer/T-cell lymphoma is a rare and aggressive malignancy with a predilection for Asian and Latin American populations. While typically presenting in the nasal cavity, extranasal forms-particularly primary pulmonary extranodal natural killer/T-cell lymphoma -are exceedingly rare and diagnostically challenging. We report the first documented case of primary pulmonary extranodal natural killer/T-cell lymphoma arising after chemotherapy for classical Hodgkin lymphoma (cHL), presenting concurrently with a nodal relapse of cHL in a 26-year-old male. Histopathological analysis confirmed synchronous diagnoses of Ebstein Barr virus-positive extranodal natural killer/T-cell lymphoma in lung tissue and Hodgkin lymphoma in lymph node biopsy. The patient responded favorably to DDGP chemotherapy followed by haploidentical stem cell transplantation. This case highlights the need for heightened clinical suspicion and histological confirmation in atypical lymphoma relapses, and underscores the complex interplay between Ebstein Barr virus infection, prior chemotherapy, and lymphomagenesis. Further research is warranted to clarify the pathogenesis and optimize treatment of metachronous extranodal natural killer/T-cell lymphoma following Hodgkin lymphoma.