Pelvic masses are among the common clinical presentations encountered in gynaecological practice, demanding astute diagnostic evaluation to determine their origin, nature, and extent. When evaluating a ovarian mass irrespective of its nature it is mandatory to evaluate for other intraabdominal pathology to provide the appropriate and complete treatment especially for colonic malignancy. While ovarian masses are frequently encountered and well-characterised within gynaecological pathology, colonic masses—particularly tumours—may also present with overlapping clinical features, especially when located in close anatomical proximity to the ovaries. The recognition of potential correlations between ovarian and colonic masses is critical, as their concurrent presence can significantly influence diagnostic procedures, surgical planning, and overall management strategies.

In this article we discuss 4 cases of ovarian mass with colonic mass differing in clinical presentation and management.

Case 1

A 57-year-old postmenopausal, multiparous lady presented with complaints ofabdominal pain. On examination, an abdominopelvic mass of 20 weeks in size in the right iliac fossa was palpable per abdomen, and bilateral pelvic masses were palpable on rectovaginal examination. Tumour markers: CA125 -26.7 U/ml, and CEA- 2 ng/ml. An 18FDG PET-CT showed a metabolically active tumour in the caecum (SUVmax 13.8) with regional lymph nodal spread, retroperitoneal lymph nodal metastasis (SUVmax 3.9), and bilateral ovarian masses probably metastases (SUVmax 17) (Fig 1). With the imaging findings, a diagnosis of carcinoma caecum with bilateral Krukenberg tumour was made. The colonoscopy showed a bulky, friable ulceroproliferative growth in the caecum at the Ileocaecal valve region. Biopsy from the caecal growth was suggestive of carcinoma, and immunohistochemistry (IHC) was positive for PAX8, WT1, p53, and p16 and negative for CK 7, CK 20, & SATB2 (Fig. 2). A final diagnosis of high-grade serous carcinoma compatible with ovarian primary was made based on the IHC reports. After a multidisciplinary board discussion, the patient was planned for comprehensive staging surgery. The patient underwent a staging laparotomy. Intraoperatively, there were bilateral adnexal masses with no peritoneal disease. The cecum was distended with a mass within, and the surface was grossly normal (Fig 3). Primary cytoreductive surgery (hysterectomy, bilateral salphingo-ophorectomy, pelvic peritonectomy, bilateral pelvic and para-aortic lymph node dissection, total omentectomy, and right hemicolectomy) was done. Histopathological examination showed high-grade serous carcinoma of the right ovarian and left fallopian tubes with microscopic pelvic peritoneal disease (Fig. 4, 5). Peritoneal cytology showed no atypical cells. The origin of the left-sided adnexal mass was the fallopian tube. The caecal growth was 7.3x6.2x5.2cm with transmural involvement on microscopy. Four lymph nodes near the cecum were positive for malignancy. She received six cycles of adjuvant chemotherapy with paclitaxel and carboplatin and is disease-free after two years of follow-up.

Case 2

A 56-year-old postmenopausal multiparous woman with a family history of breast and ovarian cancer in first-degree relatives was diagnosed with breast cancer in 2023 and tested BRCA1-positive. She underwent a left mastectomy with sentinel node biopsy on December 19, 2023, with histopathology confirming invasive breast cancer (pT2N0). Following adjuvant chemotherapy, she completed treatment on June 11, 2024. During follow-up in January 2025, an abdominal ultrasound revealed a right ovarian cyst with septations (4.7 × 2.7 cm), and CA 125 was elevated (109 IU/ml). She underwent staging laparotomy on February 17, 2025, where intraoperative findings showed a complex solid cystic mass (8 × 6 cm) in the right ovary, two omental nodules, and an incidental finding of a 6 × 5 cm growth in the descending colon, with no peritoneal disease. The right pelvic and paraaortic lymph nodes were enlarged. She underwent total abdominal hysterectomy, bilateral salpingo-oophorectomy, supracolic omentectomy, systematic pelvic and paraaortic lymphadenectomy, and extended left hemicolectomy. Histopathology confirmed high-grade serous carcinoma of the right ovary, with metastasis to the omentum and descending colon. The endometrial cavity showed a polypoidal mass, consistent with endometrioid adenocarcinoma (Grade 1), with <50% myoinvasion and no lymphovascular invasion. Pelvic and paraaortic lymph nodes were free of metastasis. Molecular testing was negative for POLE mutation, and IHC MMR indicated a low probability of MSI-H, with p53 also negative.

Case 3

A 50-year-old multiparous woman, with a history of surgical menopause 11 years back following a total abdominal hysterectomy for heavy menstrual bleeding (postoperative histopathological records unavailable), presented with a two-month history of colicky abdominal pain localized to the right hypochondriac and right iliac fossa regions. The pain was relieved with analgesics.

General examination showed normal findings. On per abdominal examination, a suprapubic mass measuring approximately 10 × 10 cm was palpable, with no ascites. Per vaginal examination confirmed a pelvic mass fixed to the vaginal vault. Routine investigations, including tumour markers, revealed Serum CA 125 levels of 13.1 U/ml and CEA levels of 8.03 ng/ml. Contrast-enhanced computed tomography (CECT) revealed a multiloculated cystic lesion measuring 11.1 × 7.3 × 9.5 cm, with enhancing internal septations in the left pelvis extending into the lower abdomen, without a solid component. The right ovary measured 4.1 × 2.4 cm. Additionally, colo-colic intussusception of the ascending colon was noted with preserved bowel wall vascularity.

During laparotomy, intraoperative findings included a left ovarian cystic mass of 10 × 10 cm. A frozen section analysis identified the mass as mucinous cystadenoma. The right fallopian tube and ovary appeared grossly normal, and no ascites was observed. Colo-colic intussusception of the ascending colon was confirmed, with the cut section revealing a 4 x 4 cm growth within the colonic lumen. The patient underwent bilateral salpingo-oophorectomy, and right hemicolectomy with complete mesocolic excision, central vascular ligation, and ileo-transverse anastomosis.

Histopathological findings confirmed left ovarian mucinous cystadenoma and grade 2 adenocarcinoma of the ascending colon (stage pT3N0), with a low probability of microsatellite instability-high (MSI-H).

Case 4

51 Years old P2L2 lady presented with C/o pain abdomen for a duration of 10 days, sudden onset pain with increasing severity. Patient was admitted and managed with analgesics at a hospital near her residence. The patient did not find symptomatic improvement; hence, she consulted a medical college hospital near her place. She was diagnosed with an ovarian mass with a high possibility of malignancy and was planned for further evaluation and management. The patient self-referred to our hospital. On initial presentation, the patient was complaining of abdominal pain, vomiting and passing foul-smelling, blackish fluid on and off. H/o low-grade fever and vomiting. Her ca125 – 90.3U/ml and CEA – 1.36ng/ml. She was evaluated with CECT abdomen and pelvis, which was suggestive of ovarian mass with no e/o rupture, haemorrhage and torsion. Multiple air fluid levels were present within the mass; hence, imaging with oral and rectal contrast was taken. The CT scan was suggestive of the possibility of sealed sigmoid perforation. The patient was taken up for surgery with consent for bowel resection and anastomosis, and a stoma.

Intraoperatively, the omentum and small bowel were adherent to the uterus, bladder and pelvic side wall; the adhesions had walled off the entire pelvis from the peritoneal cavity. On dissection of omentum and small bowel adhesions, a cavity walled by the structures mentioned above, containing 2 litres of foul-smelling thick collection with faecal matter and pus, was opened. Pelvic collection drained and a perforation in sigmoid colon plugged by small bowel loop identified. Both tubes were distended with fluid and thickened. The right ovary showed a mass of 11 x 10 x 8 cm. The left ovary was enlarged with a cyst 0f 4x4x3cm. The uterine serosa appeared inflamed with no obvious growth. Hysterectomy with BSO, Hartmann’s procedure, right hemicolectomy, ileo-colic (transverse colon) anastomosis and descending colon end stoma were done. Final histopathology confirmed-thickness inflammation of the sigmoid colon wall with perforation of the lumen, appendicitis with perforation of the appendix, right ovarian mucinous cyst adenoma, left ovarian corpus luteal cyst, and uterine serositis. The immediate post-operative period was uneventful. 4 weeks after the initial surgery, the patient developed subacute intestinal obstruction, CTs scan was suggestive of no fluid collection and possibility of bowel adhesions. She was managed conservatively.

The clinical features are compared in Table 1 as below.

Table 1

This case series emphasises the intricate relationship between ovarian and colonic pathologies, concentrating on diagnostic and treatment considerations, particularly in cases with synchronous or secondary tumour involvement. The examples provided highlight the diagnostic challenges posed by overlapping clinical features, such as pelvic pain, abdominal distension, altered bowel habits, and nonspecific gastrointestinal symptoms, which often delay a definitive diagnosis.

Embryologically, both the ovaries and distal colon derive from the primitive gut and gonadal ridges, resulting in a predisposition for direct contiguous spread, secondary infiltration, or metastasis. The proximity of the ovaries to the sigmoid and rectum facilitates local invasion, with cases reported of bowel wall involvement without serosal spread, implicating hematogenous routes in some metastatic pathways. Hence the most frequent sites of ovarian

cancer metastases are the pleura (33%), liver (26%), and lung (15%) and vascular metastases being less prevalent (16%)^(1,2). Colonic metastasis from ovarian primary accounts for 4–6% of all colonic malignancies⁽³⁾. The most common sites of colon involvement by ovarian metastasis are the rectum and descending colon, followed by the ascending colon. The gastrointestinal tract is usually involved by peritoneal spread and involves the seromuscular layers of the bowel.

Diagnostic approaches encompass clinical examination, which may be misleading due to overlapping presentation, and advanced imaging modalities such as ultrasound, CT, and MRI, which aid in delineating the origin and extent of pelvic masses. The utility of tumour markers, particularly CA-125 and CEA, is discussed, with the ratio of these markers offering enhanced discriminatory capability. Colonoscopy and histopathological assessment, including immunohistochemistry and molecular profiling, are pivotal for definitive diagnosis, especially in distinguishing primary tumours from metastatic lesions⁽⁴⁾.

The most common route of colonic involvement in ovarian cancer is by local contiguous spread or through serosal spread, but in cases 1 and 2, bowel involvement without serosal involvement is the presentation. Only limited number of cases have been reported with this presentation, and Table 2 summaries the reported cases from available literature.

Table 2: Reported cases of ovarian cancer with bowel involvement without serosal involvement.

Giant ovarian tumours masking underlying colonic pathology has been rarely reported. Robinson E et al. (2013) has reported a giant ovarian tumour with colonic adenocarcinoma in a 71 years-old woman(17). Maeda Y et al. (2022) published 3 cases of giant ovarian tumour with colorectal primary, conveying the significance of colonoscopy and bowel evaluation in women presenting with giant ovarian tumour(18). Nofal M et al., (2019) reported a case of mucinous colorectal carcinoma with borderline mucinous ovarian tumour describing the wide spectrum of pathologies in ovaries and colon which can coexist(19).

The fourth case in the series, a perforated sigmoid colon likely secondary to a diverticulum with an ovarian mass, highlights the importance of vigilance during the workup to prevent unexplained intraoperative surprises. Handling such a condition needs expertise from both a gynaecological oncologist and Gastrointestinal surgeons. Preoperative anticipation of such a scenario will help to prepare a team ready to handle such situations. Ishiko O et al. (2001) presented a similar case of a perforated sigmoid diverticular abscess, which was diagnosed preoperatively as an ovarian mass, and normal ovaries were found intraoperatively(20). Perforation of the sigmoid colon by ovarian tumour invasion, endometriosis and tubo-ovarian abscess has been reported in the literature.

Surgical management necessitates a multidisciplinary approach involving gynecologic and gastrointestinal oncologists, emphasizing thorough intraoperative exploration aimed at complete cytoreduction while minimizing morbidity. Notably, cases demonstrating isolated bowel wall involvement without serosal infiltration suggest alternative metastatic mechanisms, such as hematogenous spread.

The review underscores the importance of meticulous preoperative planning and comprehensive intraoperative evaluation to optimize outcomes. Recognizing the potential for primary colonic tumours masquerading as ovarian masses or vice versa reinforces the need for tailored diagnostic algorithms and strategic surgical intervention. Postoperative management, including staging, adjuvant therapies, and genetic counseling, depends critically on accurate histopathological characterization.

In conclusion, the interplay between ovarian and colonic neoplasms demands a vigilant, multidisciplinary approach facilitated by integrated clinical, radiological, and pathological assessment to improve diagnostic precision and therapeutic outcomes.

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