Uterine Extramedullary Hematopoiesis: What Is the Clinical Significance?
AA Gru, J Pfeifer, P Huettner. Washington University in Saint Louis School of Medicine, Saint Louis, MO
Background: Extramedullary hematopoiesis (EMH) represents abnormal development and growth of hematopoietic tissue outside the bone marrow. Recent studies have shown an association with myelofibrosis and myeloid metaplasia, chronic myeloproliferative disorders, or other hematologic malignancies in up to two thirds of cases. Only ten cases of uterine EMH (UEMH) have been previously reported; of these half had a concurrent or subsequently developed a clinically significant hematologic disorder. We studied a larger group of patients with UEMH to study the relationship with hematologic disorders.
Design: Cases diagnosed as UEMH between 1998 and 2007 were retrieved from our files (n=20). The slides were reviewed and categorized according to the type of specimen, uterine location, histopathologic diagnosis, number of EMH foci, and lineage composition. Clinicopathologic features recorded included age, history of an underlying hematologic disorder, baseline CBC, and subsequent work-up. Patients were followed from the time of initial diagnosis to the time of death or last follow-up.
Results: UEMH was confirmed in all 20 cases from 5 endometrial biopsies, 3 curettages and 12 hysterectomies. The mean number of EMH foci was 3.55 (range: 1-10). Eighteen cases were located in the fundus including 5 in endometrial polyps and 5 in leiomyomas. Two foci were located within the cervix. None of the patients had a concurrent gynecologic malignancy. The erythroid lineage was present in all foci; 35% also had myeloid precursors, and 20% megakaryocytes. The mean patient age was 44 years (range: 27-75 years). Twelve of 20 patients had underlying anemia (mean Hgb of 11 mg/dl, range: 5.5-15.7 mg/dl). No preexisting hematologic malignancy was identified in any of the patients. One patient had breast cancer with extensive bone metastases. Follow up information was available on 17 patients (mean 2.88 years; range 0.2-9 years). Only one patient had a bone marrow biopsy after the diagnosis of UEMH and the findings were consistent with iron deficiency anemia. None of the patients developed a significant hematologic disorder other than anemia during follow-up.
Conclusions: Based on our study, UEMH is often located in endometrial polyps or leiomyomas and frequently associated with chronic anemia. In comparison to existing literature suggesting a strong link between UEMH and hematopoietic disorders, our findings suggest that UEMH is rarely associated with serious underlying hematologic conditions and therefore should not warrant extensive hematologic work up.
Wednesday, March 11, 2009 1:00 PM
Poster Session VI # 136, Wednesday Afternoon