Heterotopic Sex Cord-Stromal Proliferation: A Case Report

Abstract

Abstract Introduction/Objective Sex cord-stromal cells at extraovarian sites are extremely rare and due to the low number of cases reported, the true incidence is unknown. We present the case of a patient with symptomatic uterine fibromas that had a benign extraovarian heterotopic sex cord-stromal proliferation. Methods/Case Report A 44-year-old female presented with pelvic pressure and discomfort. Past medical history is significant for breast cancer treated with bilateral mastectomy in 2019 followed by radiation treatments. The patient had no menses since January 2020 but had begun noticing spotting prior to the onset of her pelvic pressure and discomfort. Pelvic ultrasound revealed an enlarged uterus consistent with fibroids and a right adnexal mass. Endometrial biopsy following the ultrasound was normal. The patient desired definitive treatment and a total abdominal hysterectomy and bilateral salpingo-oophorectomy was subsequently performed. Gross examination of the surgical specimen revealed a fibroid uterus and normal appearing bilateral ovaries and fimbriated fallopian tubes. Histopathology showed a uterus with leiomyomata and serous cystadenofibromas in bilateral ovaries. The left fallopian tube fimbria showed a well-circumscribed proliferation of pale, ovoid cells in a microfollicular pattern. Rare cells with grooved nuclei were present. No significant atypia and no mitotic activity were identified. Immunohistochemical staining was positive for inhibin, WT-1, and vimentin. Negative stains include EMA, GATA-3, GCDFP 15, mammaglobin, chromogranin, and calretinin. Final diagnosis was determined to be benign fallopian tube with heterotopic sex cord-stromal proliferation. Results (if a Case Study enter NA) NA Conclusion This case highlights a rare, incidental finding. These lesions are postulated to represent non-neoplastic embryologic remnants. However, most heterotopic sex cord-stromal proliferations are found in fimbriae, which could suggest that they arise from heterotopic ovarian tissue exposed during ovulation. The incidence of these benign proliferations is expected to increase as routine sampling of adnexal structures is becoming more commonplace, which presents diagnostic challenges for pathologists.