Expression of Estrogen and Progesterone Receptors in a Tailgut Cyst with Carcinoid Tumor

Abstract

Abstract Introduction/Objective Tailgut cysts (TC) are congenital lesions that arise in the presacral space. They originate from the embryonic hindgut and usually present between the ages of 30-60, with female predominance. TCs are usually asymptomatic or can present with lower back, perianal or pelvic pain. Malignant transformation of a TC is a rare complication, with adenocarcinoma being the most common, followed by carcinoid tumor. About thirty cases of carcinoid tumors arising in a TC have been reported in the literature so far with a slight female predominance (1.5:1). Methods/Case Report We describe a 40-year-old Hispanic woman with a 9-year history of cyclic pelvic pain related to her menstrual cycles. She was diagnosed with adenomyosis and underwent hysterectomy that did not completely resolve her symptoms. Follow-up serial imaging showed a growing complex-cystic presacral mass, which was eventually excised. Grossly, there was a 3.6×3.1×2.5 cm multiloculated cystic mass filled with mucoid material. Microscopically, there were multiple cystic spaces lined by benign squamous and mucinous columnar epithelium and surrounded by smooth muscle cells. A 6-mm carcinoid tumor was found within a cyst wall and confirmed by positive synaptophysin and chromogranin staining with a Ki-67 proliferation index of <2%. Estrogen and progesterone receptor immunostains were positive in the epithelial cyst linings and the stromal cells but not in the carcinoid tumor cells. Results (if a Case Study enter NA) NA Conclusion We conclude that the diagnosis of TC should be considered in the differential of gynecologic patients with unresolved cyclic pelvic pain and that estrogen and progesterone could have an important role in the pathogenesis of TCs. Furthermore, estrogen receptors can be a therapeutic target in patients with this entity.