We report a 21-year-old postpartum woman presenting with a very rare tumor of the spleen, diffuse hemangiomatosis. Gross and microscopic examination revealed that the whole spleen was permeated by neoplastic blood vessels. Immunohistochemical staining suggested an origin from vascular endothelium (CD 31+, CD 34+, FVIII+ and CD 8-). Although steroid hormone receptors are discovered in other vascular proliferations, we report the first case of a diffuse hemangiomatosis of the spleen showing strong and diffuse immunopositivity for estrogen receptor (ER). Hormonal changes associated with pregnancy might have induced or promoted the development of diffuse splenic hemangiomatosis
