Rare case of primary peritoneal pregnancy infiltrated into the Gerota's fascia of the right kidney.

A 33-year-old, gravida 3, para 2, woman was transferred to our hospital, with acute abdominal pain. Abdominal computed tomography (CT) revealed a cystic lesion accompanied by ring-enhancement between the liver and right kidney with fluid collection in the pelvic cavity. Serum hCG value was 3100 mIU/mL. Transvaginal sonography revealed a pseudo-gestational sac in a thickened endometrium. With a preoperative diagnosis of ectopic pregnancy at 7 weeks of gestation, laparotomy was performed. Following careful removal of clots between the liver and right kidney that contained a gestational sac, continuous bleeding from a defect in the Gerota's fascia of the right kidney was noted. The postoperative course was uneventful and the serum hCG concentration decreased markedly. This case demonstrates that the Gerota's fascia is a possible site of ectopic pregnancy, and that CT can identify a pregnancy in the Gerota's fascia as well as in the liver and spleen.