Heterotopic ovarian hilus cells of the salpinx: a case report and literature review

Abstract

Ovarian hilus cells (OHCs), a counterpart of testicular Leydig cells, are usually found in the ovarian poles and produce androstenedione. Their origin remains a matter of debate, although OHCs are assumed to come from the adrenogenital primordium. OHCs are rarely observed around the poles of the ovary, including the mesoovarium, stroma (perisalpinx) of the salpinx, and the wall of paratubal cysts. Their clinical and pathological characteristics are not well-known because of their rarity. Herein, we present a case of ectopic OHCs in a 48-year-old woman. The patient underwent total hysterectomy and bilateral salpingectomy for vaginal bleeding due to multiple leiomyomas. We incidentally found OHCs in the stroma of the infundibulum of the salpinx, just beneath the tubal epithelium. Their size was less than 1 mm, and they were composed of large cells with central round nuclei and abundant clear or granular cytoplasm. OHCs share morphological and immunohistochemical profiles with ectopic adrenal glands, and the differential diagnosis is sometimes difficult. They do not exhibit microscopic encapsulation or the normal adrenal cortex zonation pattern. The patient was discharged and did not show any abnormal findings during 19 months of follow-up. Analyzing the characteristics of testicular Leydig cells will help understand how OHCs develop and why heterotopic OHCs occur in and around the salpinges.