Hidden treasures: Incidental findings in two cases of chronic subdural hematoma

BACKGROUND: Extramedullary hematopoiesis (EMH) and plasmacytomas occurring within the cranium are rare entities. CASE DESCRIPTION: We review two cases in which patients presented with subdural hematoma and underwent evacuation. On routine histopathologic examination of their membranes, both patients were subsequently found to have focal EMH, as well as a clonal plasma cell proliferation in one case. CONCLUSION: EMH is rare and usually found in individuals with profound and chronic anemia. However, this entity may be more common in chronic subdural hematomas. Solitary extraosseous plasmacytoma is exceedingly rare in the cranium, and its presence in chronic subdural hematoma membranes is of uncertain significance. The cytokine milieu that promotes organization of chronic subdural hematomas may play a role in the establishment of both of entities in this location.