A previously healthy 70yo female presented to the emergency department after a syncopal episode. The patient had been feeling progressively fatigued for 2 months prior to presentation, yet had not seen a physician in years. On admission, she complained of vague abdominal discomfort, fullness, and early satiety for 2 weeks prior to presentation. She also had 3 episodes of watery diarrhea on the day of admission. She denied nausea or vomiting. Patient appeared pale, but vital signs were stable. The remainder of the physical exam was unremarkable except for right lower quadrant tenderness on abdominal exam. Laboratory findings revealed WBC count of 4.3 k/ul, Hgb of 7.7 g/dL and platelet count of 213 k/ul. Abdominal and pelvic imaging was obtained which showed a 7.3 by 8.4 by 6.9 cm mass in the posterior pelvis. Biopsy of the mass revealed a hypercellular marrow tissue with trilineage hematopoiesis consistent with an extramedullary hematopoietic (EMH) site. A bone marrow biopsy was then performed which showed normocellular marrow with relative erythroid hyperplasia consistent with low grade myelodysplastic syndrome and refractory anemia with ringed sideroblasts. FISH testing was positive for deletion 5q. The patient was initially treated with transfusions. The mass was found to be unresectable secondary to location and proximity to vasculature and therefore radiation therapy was initiated. She completed low dose radiation to the abdomen and pelvis over 24 days with repeat imaging showing minimal improvement. The plan is now to transfuse as needed and begin lenolidomide.
Extramedullary hematopoiesis is a rare finding especially if located outside the liver and spleen; in which case it is termed nonhepatosplenic EMH (NHS–EMH). The most common site involved is paravertebral and this is typically seen in the setting of myelofibrosis with myeloid metaplasia or thalassemia although it can also be found in other disorders including sickle cell, osteoporosis, polycythemia, immune thrombocytopenic purpura, and myelodysplastic syndrome. Due to the rarity of this condition, there is no conclusive data defining the treatment recommendations. For symptomatic patients who are found to be unresectable, such as this case; low dose radiation is the usual therapy.
The purpose of this case report is to highlight a common presentation of abdominal pain with an uncommon diagnosis.
Figure 1MRI of the pelvis with contrast showing heterogeneous mass in the presacral space.