Castleman's disease: a rare presentation in a retroperitoneal accessory spleen, treated with a minimally invasive robotic approach.

Unicentric Castleman's disease (UCD) is a rare disorder of unknown etiology characterized by localized lymphoid tissue proliferation and interfollicular hypervascularity. A 33-year-old Caucasian female presented with vague abdominal discomfort and pain with pressure. Ultrasound and computed tomography detected a large peripancreatic mass. Robotic-assisted resection of the mass along with en bloc dissection of the encased left adrenal gland was done. Frozen section examination confirmed UCD hyaline vascular variant in a retroperitoneal accessory spleen. Preoperative diagnosis of UCD is difficult due to its lack of specific symptoms and its cytologic similarity to reactive lymphadenopathy and other lymphoproliferative disorders. Surgical resection is standard treatment and provides the pathological specimen required for diagnostic confirmation. Here, robotic-assisted laparoscopy allowed visualization, mobilization, precise resection and extraction of the mass from a difficult to access retroperitoneal region.