Hydrosalpinx in a premenarcheal 14-year-old girl with the proliferation of smooth muscle cells in the isthmus of the fallopian tube: A case report.

Hydrosalpinx is rare in childhood, and its pathogenesis may differ from that in reproductive-aged women. Herein, we report a case of hydrosalpinx in a premenarcheal 14-year-old girl, which might be caused by thickening of the smooth muscle of the fallopian tube. The patient had recurrent right lower abdominal pain and was referred to our hospital with a suspected adnexal tumor. Laparoscopy revealed a hydrosalpinx with complete obstruction of the fimbria and scar-like stenosis of the proximal ampulla. Right salpingectomy was performed because of a severe hydrosalpinx. As the patient was a virgin and a vaginal culture showed normal flora, ascending infection to the fallopian tube was not considered to be the cause of the hydrosalpinx. Histopathological examination revealed that the resected fallopian tube had a markedly dilated lumen with no inflammatory cell infiltration. Immunohistochemically, estrogen- and progesterone-positive smooth muscle proliferation was found at the isthmus of the fallopian tube.