On the Origin of Abdominal Venous Leiomyosarcomas: The Role of the Sex-Hormone Drainage Pathways.

Abstract

We hypothesized that abdominal venous leiomyosarcoma (AV-LMS) disproportionately originates in veins of the sex-hormone drainage pathway (SHDP). Our purpose was to classify the anatomical origin of AV-LMS in a large cohort using imaging and explore prognostic implications. A retrospective review of imaging of all patients presenting with abdominal non-uterine LMS at a single tertiary oncology center was performed. Inclusion criteria were a biopsy-proven LMS of non-uterine abdominal/pelvic origin with pretreatment enhanced computed tomography (CT)/magnetic resonance imaging (MRI). Patients with uterine LMS or prior radiation were excluded. LMS site of origin was assigned by one expert radiologist and indeterminate sites were reviewed with a second external expert radiologist. Locations of inferior vena cava (IVC) tumors were subclassified based on a modification of prior literature. SHDP was defined as originating from ovarian/testicular vein, distal left renal vein, adrenal vein or mid-IVC (IIA). One hundred fifty-five (155) patients were included (92/152 (61%) female) with distant metastases found at presentation in 23/155 (14.8%). Most common organs of origins were veins (84/152, 55.3%), gastrointestinal (24, 15.8%), genital (11, 7.2%) and paratesticular/spermatic cord (11, 7.2%). For venous LMS, the adrenal (both sexes), mid-IVC (IVC IIA, females) and ovarian veins had the highest relative predilection for abdominal non-uterine LMS. Eighty-four (84/152, 55.3%) of tumors were SHDP. On multivariable analysis, both size and SHDP were significant predictors of distant metastases at presentation (P = 0.01), while sex, age, organ system/site and grade were not. For both sexes, tumors arising from SHDP constitute the majority of AV-LMS and may impart a significantly lower risk of metastatic disease at presentation. Among veins, the adrenal veins had the highest predilection for LMS.