# Fever of Unknown Origin Unveiling Bone Marrow Necrosis Secondary to Diffuse Large B-cell Lymphoma

## TL;DR

A 75-year-old woman with fever and anemia was found to have bone marrow necrosis caused by diffuse large B-cell lymphoma, which did not improve despite successful lymphoma treatment.

## Contribution

This case highlights the rare and persistent nature of bone marrow necrosis despite remission of the underlying lymphoma.

## Key findings

- The patient showed complete metabolic response of lymphoma after R-CHOP treatment.
- Bone marrow necrosis persisted despite remission of the lymphoma.
- The patient exhibited fever, anemia, and elevated LDH but lacked thrombocytopenia or a leukoerythroblastic smear.

## Abstract

Bone marrow necrosis (BMN) is a very rare pathological finding that may arise in the context of numerous underlying conditions. It has been linked to hematologic malignancies, solid tumors, sickle cell disease, various infections, and certain medications. Advances in hematopathology have contributed significantly to the improved identification and diagnostic accuracy of BMN. We report a case of a 75-year-old woman who was evaluated for anemia and fever of unknown origin. Histopathological examination of a bone marrow biopsy revealed widespread necrosis accompanied by infiltration with diffuse large B-cell lymphoma (DLBCL). Positron emission tomography (PET)/computed tomography (CT) showed pathologic uptake in the skeletal system and in multiple lymph node regions, on both sides of the diaphragm. Following treatment with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP), a repeat bone marrow biopsy demonstrated persistent, complete BMN, whereas a subsequent PET/CT scan revealed complete metabolic response of the lymphoma, indicating a discordance between remission of lymphoma and the persistence of BMN. A comprehensive literature review was performed, and the clinical features of our patient were compared with data from previously published studies. The patient exhibited several characteristics commonly observed in the literature, including fever, anemia, and elevated lactate dehydrogenase (LDH) levels. However, the patient did not present with thrombocytopenia or a leukoerythroblastic peripheral smear. According to existing literature, the primary prognostic factor for patients with BMN is the effective control of the underlying disease. However, in our case, while remission of lymphoma was achieved, it was not associated with improvement in BMN. Areas for further discussion and advancement in the understanding of the etiology, diagnosis, and management of BMN are also highlighted.