RESUMEN
BACKGROUND: Uterine leiomyosarcomas are very rare and highly aggressive tumors that have a high rate of recurrence and poor prognosis, even when early diagnosed. Due to their relative rarity, there is limited research on optimal management strategies. CASE PRESENTATION: A 60-year-old woman with a history of an asymptomatic uterine leiomyoma presented in October 2015 with postmenopausal bleeding and a friable vaginal cyst that bled when palpated. A partial cystectomy was performed, and malignant-like cystic and solid components were identified. Histopathology diagnosed an unclassifiable malignant epithelioid tumor. Subsequent imaging studies identified a malignant uterine tumor, a metabolically active vaginal lesion, and two benign leiomyomas. An anterior pelvic exenteration (colpectomy, hysterectomy, bilateral adnexectomy, total cystectomy, and cutaneous ureteroileostomy ad modum Bricker) were performed by laparotomy in March 2016. Examination of the surgical specimens identified a 75 × 75-mm leiomyoma, an 80 × 30-mm infiltrating mesenchymal uterine lesion with vascular invasion and tumor emboli, and a 60 × 30-mm perivascular vaginal tumor. Immunohistochemistry indicated a phenotypic transition from a uterine leiomyosarcoma to a vaginal epithelioid lesion; marker expression changed from the uterine tumor actin+/desmin+/caldesmon+/CD10- phenotype, through the tumor emboli, to an actin-/desmin-/caldesmon-/CD10+ phenotype in the vaginal lesion. A high-grade uterine mesenchymal tumor and vaginal metastasis were diagnosed. Adjuvant chemotherapy with docetaxel, gemcitabine, and doxorubicin commenced in May 2016 and treatment has been well tolerated. CONCLUSIONS: Differentiating leiomyosarcoma from leiomyoma is challenging and few tools other than microscopic evaluation are available. Vaginal compromise in leiomyosarcoma usually results from tumor extension, not hematogenous metastasis. A vaginal metastasis is a very rare initial presentation. We have found only two cases like this described on published literature. The atypical clinical and histological presentation in our case complicated diagnosis and delayed treatment. An early diagnosis and complete surgical clearance gives the best chance of survival, and imaging tools should be applied early in instances of new suspicious malignant lesions.