A mesorectal incidentaloma: Rare localization of Castleman disease (Case report).

Incidentalomas are defined as tumors or pseudo-tumoral masses accidentally discovered during clinical and imaging investigations. We present a 51-year-old female patient who presented at the gynecology service for genital bleeding caused by uterine fibromatosis. Computerized pelvic tomography showed an engorged uterus completely deformed by numerous intramural and submucosal nodular structures suggestive of multiple fibroids. Behind the uterus, a well-defined, iodophilic, 49/51 mm diameter, tissue-shaped, nodular mass was identified, with pushing borders into the adjacent fat and showing a mass effect on the rectum against which it retained a demarcation zone. A conclusion of the histopathological examination was made. Histopathological aspects and immunohistochemical tests supported the diagnosis of Castleman disease (CD) variant vascular hyaline variant. The mesorectum is a particularly and extremely rare localization for CD, and preoperative diagnosis is difficult to achieve. The correct surgical attitude in the case of an incidental finding in this localization is the extensive resection that satisfies the presumption of a neoplastic formation.