This is a classic case of subdural hematoma that contains many accumulated benign nucleated and heterogeneous white blood cells. Sometimes these cells are distributed in a vague laminar or layered fashion, or are concentrated on the surface of hematomas. Looking at them under high power microscopy shows them to be heterogeneous (some are mononuclear while others polymorphonuclear, some are lymphoid/monocytic while others are myeloid, band forms and mature eosinophils may be abundant), but none display cytologic/nuclear atypia seen in usual lymphoproliferative disorders. Mitotic figures may be found, and small collections of extramedullary hematopoiesis are common. While many cells in the photos appear plasmacytoid with round nuclei and eosinophilic eccentric cytoplasm, these cells do not have the characteristics of plasma cells. Plasmacytoma and chloroma do occur in the meninges, so it is important to rule these entities out by doing immunohistochemical stains if component cells appear very monotonous. This case, however, raises no suspicion for malignancy in me.
This is a classic case of subdural hematoma that contains many accumulated benign nucleated and heterogeneous white blood cells. Sometimes these cells are distributed in a vague laminar or layered fashion, or are concentrated on the surface of hematomas. Looking at them under high power microscopy shows them to be heterogeneous (some are mononuclear while others polymorphonuclear, some are lymphoid/monocytic while others are myeloid, band forms and mature eosinophils may be abundant), but none display cytologic/nuclear atypia seen in usual lymphoproliferative disorders. Mitotic figures may be found, and small collections of extramedullary hematopoiesis are common. While many cells in the photos appear plasmacytoid with round nuclei and eosinophilic eccentric cytoplasm, these cells do not have the characteristics of plasma cells. Plasmacytoma and chloroma do occur in the meninges, so it is important to rule these entities out by doing immunohistochemical stains if component cells appear very monotonous. This case, however, raises no suspicion for malignancy in me.