Giant Abdominopelvic Leiomyosarcoma of Indeterminate Pelvic Origin: A Multimodality Imaging and Surgical Diagnostic Dilemma

Vishal J, Chethan T. N, Prashant G Patil

Abstract: Background: Determining the organ of origin of giant abdominopelvic masses remains a major diagnostic challenge because the distortion of normal pelvic anatomy can obscure anatomical relationships. Multimodality imaging plays a pivotal role in lesion characterization; however, accurate localization may remain difficult despite advanced imaging techniques. Case Presentation: A 50-year-old woman presented with menorrhagia, dysmenorrhea, irregular menstrual cycles, and progressive abdominal distension. Clinical examination revealed a large abdominopelvic mass corresponding to a 28-30-week gravid uterus. Initial ultrasonography suggested a large uterine mass with an additional posterior wall fibroid. Contrast-enhanced magnetic resonance imaging demonstrated a giant, predominantly solid pelvi-abdominal lesion with heterogeneous T2 hyperintensity, restricted diffusion, and heterogeneous post-contrast enhancement, corresponding to an O-RADS MRI score of 5. Contrast-enhanced computed tomography demonstrated omental fat stranding, nodularity, and the ovarian vascular pedicle sign, favoring an adnexal origin. Despite comprehensive multimodality imaging, the precise organ of origin remained indeterminate because of extensive distortion of the pelvic anatomy. The patient underwent staging laparotomy with total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, bilateral pelvic lymph node dissection, and appendicectomy. Histopathological examination with immunohistochemistry established the diagnosis of a high-grade leiomyosarcoma (FNCLCC Grade 3). Conclusion: This case highlights the complementary role of ultrasonography, MRI, and CT in evaluating giant pelvic masses while emphasizing their limitations in determining the organ of origin in exceptionally large tumors. Recognition of ancillary imaging findings, including the ovarian vascular pedicle sign, together with multidisciplinary clinicopathological correlation, is essential for accurate diagnosis and optimal surgical management.

Keywords: Giant abdominopelvic mass, Leiomyosarcoma, Multimodality imaging, Magnetic resonance imaging, Computed tomography, O-RADS MRI, Ovarian vascular pedicle sign

How to Cite?: Vishal J, Chethan T. N, Prashant G Patil, "Giant Abdominopelvic Leiomyosarcoma of Indeterminate Pelvic Origin: A Multimodality Imaging and Surgical Diagnostic Dilemma", Volume 15 Issue 7, July 2026, International Journal of Science and Research (IJSR), Pages: 2271-2277, https://www.ijsr.net/getabstract.php?paperid=SR26727210023, DOI: https://dx.doi.org/10.21275/SR26727210023

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