What question did this study set out to answer?

This review examines the clinical characteristics, treatment responses, and outcomes associated with extramedullary hematopoiesis in myelofibrosis.

July 2, 2026Open Access

A systematic review of 47 published cases of extramedullary hematopoiesis in myelofibrosis: clinical patterns, treatment responses, and prognostic implications

Key Points

This review examines the clinical characteristics, treatment responses, and outcomes associated with extramedullary hematopoiesis in myelofibrosis.
Systematic review of 36 publications from 2011 to 2025, reporting 47 cases of EMH in myelofibrosis.
Analysis included demographics, anatomic distribution, presentations, diagnostics, treatments, and outcomes.
Patients treated with JAK inhibitors and other therapies were evaluated for clinical response and survival.
Median age of patients was 68 years; 75% experienced symptomatic onset, including dyspnea and abdominal pain.
Treatment with ruxolitinib led to symptom relief in 40% of patients, while 38% mortality was observed, mainly due to EMH-related complications.
Atypical EMH indicates advanced disease stage with poor prognosis, yet responds to targeted therapies, necessitating monitoring and potential transplant.

Abstract

Abstract Extramedullary hematopoiesis (EMH) in myelofibrosis manifests beyond classical splenomegaly, causing life-threatening complications, yet lacks systematic characterization in the JAK inhibitor era. We systematically reviewed 36 publications (2011–2025), available on PubMed database, reporting 47 unique myelofibrosis-associated EMH cases, analyzing demographics, anatomic distribution, presentations, diagnostics, treatments, and outcomes. Median age was 68 years (range 43–82; M: F 26:21); primary myelofibrosis predominated (64%). EMH favored atypical sites: abdominopelvic (28%), thoracic (26%; pulmonary/pleural), serosal (17%), cutaneous (13%). Symptomatic onset occurred in 75% (dyspnea 28%, abdominal pain 21%). CT/MRI revealed characteristic lobulated masses with T2 hypointensity; biopsy confirmed trilineage hematopoiesis with atypical megakaryocytes (CD61+). Ruxolitinib-based regimens, administered in 19 patients (40%) as EMH-directed therapy, yielded rapid palliation (dyspnea/ascites resolution), complemented by radiotherapy (11%) and splenectomy; HSCT achieved complete remission in one case. Mortality reached 38% (median follow-up 5 months), driven by EMH-related organ failure or AML transformation. Atypical EMH signals advanced myelofibrosis with dismal prognosis, responsive to JAK inhibitors/locoregional therapies but highlighting sanctuary biology. Systematic surveillance and transplant referral are imperative; prospective registries are needed to refine risk models and test novel antifibrotics.

KI fragen

Bookmark

View Full Paper