Paratubal Leiomyoma Mimicking Ovarian Malignancy: A Case Report and Literature Review

Background and Clinical Significance: A paratubal leiomyoma is an exceptionally rare benign smooth muscle tumor arising from paratubal tissue, with only sporadic cases reported in the literature. Case Presentation: We present the case of a 72-year-old postmenopausal woman with intermittent spotting for three months. A pelvic examination revealed a retained intrauterine device, which was removed along with an old sanguineous discharge. A transvaginal ultrasound demonstrated a complex left adnexal mass with calcifications, and computed tomography (CT) confirmed a 7.8 × 5.5 × 4.7 cm lesion suggestive of an ovarian malignancy. Tumor markers showed mildly elevated CA-125 and carcinoembryonic antigen (CEA) levels. Endometrial sampling using a hysteroscopy and curettage revealed hyperplasia without atypia. The patient underwent a total laparoscopic hysterectomy with a bilateral salpingo-oophorectomy. A diagnostic laparoscopy revealed a well-circumscribed solid mass arising from the mesosalpinx, separate from the ovary and fallopian tube and consistent with a paratubal mass, which was successfully excised laparoscopically. Frozen sections suggested a fibroma, and the final pathology confirmed a paratubal leiomyoma with hyalinization, accompanied by adenomyosis and simple endometrial hyperplasia. The patient recovered uneventfully, and the 6-month follow-up showed no recurrence. This case highlights the diagnostic challenge of differentiating paratubal leiomyomas from ovarian tumors based on imaging alone. Histopathological examination is essential for confirmation. Conclusions: Awareness of paratubal leiomyomas as a differential diagnosis may prevent overtreatment and guide the appropriate surgical management of postmenopausal women presenting with adnexal masses.