Hamartoma of the spleen.

Splenic hamartoma is a rare, benign vascular proliferation that is often found incidentally while working up other complaints or at autopsy. Women more commonly present with symptoms related to mass effect than men. Histologic findings consist of unorganized vascular channels of varying width, with intervening red pulp-like disorganized stroma with or without lymphoid follicles. The endothelial cells are similar to those of normal splenic sinuses. Although rendering a diagnosis can be difficult, endothelial cells that are positive for CD8 are a key feature that differentiate hamartoma from other vascular lesions of the spleen. Clinical, radiologic, and histologic correlation is essential to ensure this benign lesion is not mistaken for malignancy.