Small Bowel Adenocarcinoma Presenting as a Chronic Pelvic Mass Mimicking Gynecologic Malignancy: A Case Report and Focused Narrative Review.

Abstract

Background: Small bowel adenocarcinoma (SBA) is considered an unusual malignancy with vague presentations thus risk of delayed diagnosis. Despite being rarely reported in the literature, SBA can present with gynecological manifestations, especially adnexal mass, misleading surgeons in dealing with it as a primary gynecological malignancy.

Methods: We report a case of a 60 year old female patient who had SBA with pelvic mass as initial presentation. Identification of intestinal origin was done intraoperatively. Surgical resection of tumor and adnexal involvement with referral for oncological chemotherapy was done. Through this case we highlight the challenges experienced by surgeons in diagnosing SBA with gynecological disease, as well the clinical implications of atypical SBA presentations. Reported following CARE guidelines. In addition to the case reported, a focused narrative review of literature was performed. Searching Pubmed database from inception to December 2025 using related keywords, identification of case reports reporting SBA presentation with gynecological disease was done. Data related to patient demographics, clinical manifestations, diagnostic, treatment strategies, and oncological outcomes, were extracted and pattern identification was conducted. A diagnostic algorithm was developed and presented to improve diagnostic delay in approaching adnexal masses with "Red Flags" suspicious of SBA.

Results: Fourteen cases describing small bowel adenocarcinoma (SBA) presenting with gynecologic manifestations were identified - published between the years (1995-2024). Approximately the age range of patients was between 12 and 65 years with most patients presenting in the fifth and sixth decades. The jejunum was the most common primary tumor site (10/14 cases, 71%), followed by the ileum (4/14 cases, 29%). The most common initial presentation reported across the studies was ovarian/adnexal mass. Diagnostic delay was common, ranging from several weeks to over 12 months, with SBA rarely suspected preoperatively. Recurrent red flags included iron-deficiency anemia, chronic gastrointestinal symptoms, unintentional weight loss, obstructive symptoms, disproportionate ovarian tumor size, and discordance between clinical presentation and gynecologic findings. Ovarian metastases were present in all reported cases (14/14 cases, 100%), while peritoneal, mesenteric, nodal, hepatic, and uterine involvement occurred less frequently. The definitive diagnosis was established following surgical exploration through histopathological and immunohistochemistry evaluation. Surgical management was dependent on timely diagnosis, with both bowel and gynecological resections required, followed by postoperative chemotherapy. Outcomes were also dependent on disease stage at the time of diagnosis.

Conclusion: Atypical adnexal masses in association with gastrointestinal or systemic red flags should raise the possibility of SBA. We propose a clinical diagnostic framework to help general surgeons and gynecologists with early identification of SBA presenting as pelvic mass, thus providing appropriate management of this rare clinical entity.