[Extramedullary hematopoiesis, a rare complication of sickle cell disease: A six-case series and literature review].

Introduction: Extramedullary hematopoiesis (EMH) is very rarely described during sickle cell disease (SCD). Our aim was to describe six cases of EMH occurring in adult SCD patients and to conduct a literature review.

Methods: Retrospective, descriptive, and monocentric study, identifying all cases of EMH recorded in our cohort of adult SCD patients, up to April 2024. A literature review via PubMed included thirty-five articles (44 patients).

Results: Six patients (4 men, 83.3% with SS genotype [n=5], 1 SC), with a median age of 22 (range 12-64) years at the time of EMH diagnosis were included. Four patients (66.7%) had an aseptic osteonecrosis of the hip. The localization of EMH varied: paravertebral (n=3), peri-articular in the hip (n=1), adrenal (n=1), hepatic (n=1), splenic (n=1) and was similar to the localizations reported in the literature. EMH was symptomatic at diagnosis in half of the cases. The diagnosis was established by histology (n=3/3) and/or typic magnetic resonance imaging (MRI) (n=4/4). The median baseline hemoglobin was 9.1 (extremes 5.8-10.9) g/dL. A watch-and-wait approach was primarily observed.

Conclusion: EMH in SCD patients appears to be rare, with varied localizations. Its diagnosis is made with MRI and/or biopsy, and its treatment is not consensual.