Low-grade serous ovarian carcinoma (LGSC) accounts for approximately 2% of epithelial ovarian cancers (1). It exhibits an indolent yet persistent course, with relative resistance to cytotoxic chemotherapy. Complete surgical resection (R0) remains the strongest prognostic factor (2–4), yet achieving this is often complicated by anatomical extension and functional limitations.

Advanced LGSC with extra-pelvic invasion poses unique challenges that demand a balance between surgical radicality and quality of life (QOL). Although recent guidelines, including the NCCN (2025) and ESMO (2023), emphasize the role of endocrine and targeted therapies in both advanced and recurrent disease (5, 6), initial cytoreductive surgery continues to pivotal role in selected patients. Although extra-pelvic invasion involving major vessels or paraspinal region is generally considered a contraindication for surgery, the indolent biology of LGSC suggests that complete resection—even in anatomically demanding situations—may confer substantial survival advantage compared with high-grade malignancies.

Here, we report a case of FIGO stage IVB LGSC with right inguinal invasion successfully managed through coordinated multidisciplinary surgery. We also introduce a conceptual framework—the “Four Surgical Limits”—to redefine operative boundaries in gynecologic oncology.

A 62-year-old woman presented with progressive right inguinal swelling that she first noticed in early May. The mass gradually enlarged, prompting evaluation at a referring hospital. She also reported abdominal distension and persistent abdominal pain that interfered with her daily activities prior to referral. MRI revealed a 9 cm irregular right inguinal mass with heterogeneous internal characteristics and suspected invasion of the femoral vein and lower abdominal wall. In addition, bilateral adnexal tumors were identified, raising concern for an ovarian malignancy with extra-pelvic extension. Transvaginal ultrasound confirmed bilateral complex adnexal masses with preserved mobility. Serologic evaluation demonstrated mildly elevated CA125 (59.8 U/mL), whereas CA19-9, TFPI2, and HE4 were within normal limits. PET-CT revealed high FDG uptake in the bilateral ovarian tumors (left: SUVmax 8.2; right: SUVmax 5.7), the right inguinal lesion (SUVmax 10.2), and multiple pelvic (SUVmax 8.3) and para-aortic lymph nodes (SUVmax 8.94), suggesting systemic nodal involvement without evidence of additional distant metastases (Figure 1).

Given the unusual presentation of a large inguinal tumor with concurrent adnexal masses, an ultrasound-guided core-needle biopsy of the inguinal lesion was performed. Histopathology was consistent with low-grade serous carcinoma (PAX8+, WT1+, ER+, p53 wild-type) (Supplementary Figure 1). These findings supported the diagnosis of ovarian LGSC with inguinal and nodal metastases, corresponding to a preoperative FIGO stage of IVB.

Following multidisciplinary tumor board discussion, curative-intent resection was selected after a comprehensive review of oncologic, anatomic, functional, and collaborative feasibility. From an oncologic perspective, LGSC is intrinsically resistant to cytotoxic chemotherapy and has limited radiotherapy sensitivity, making meaningful tumor shrinkage with neoadjuvant chemotherapy or upfront targeted agents—including MEK inhibitors—unlikely. Thus, primary debulking surgery (PDS) offered the highest probability of disease control. Anatomically, the absence of ascites and radiologic peritoneal carcinomatosis suggested that complete intra-abdominal cytoreduction was achievable. The major challenge involved the right inguinal mass with suspected vascular invasion.

Orthopedic oncologists confirmed that the inguinal tumor could be resected by wide en bloc resection aiming for negative surgical margins, including partial involvement of the femoral vein, with the feasibility of primary venous repair. Plastic surgeons also confirmed the feasibility of soft-tissue reconstruction using an anterolateral thigh (ALT) flap.

Although no formal preoperative consultation with gastrointestinal surgery was obtained due to the absence of radiologic findings suggestive of bowel involvement, the gastrointestinal team remained on standby and agreed to provide intraoperative support should bowel resection become necessary. Potential postoperative morbidities—including lymphedema, lymphatic leakage, and lower-limb sensory or motor deficits—were discussed in detail. The multidisciplinary team concluded that the benefits of complete macroscopic resection outweighed these risks (Figure 2).

The surgical procedures included total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, systematic pelvic and para-aortic lymphadenectomy, and en bloc resection of the right inguinal lesion with partial femoral vein involvement.

Systematic lymphadenectomy was performed because multiple pelvic and para-aortic lymph nodes were diffusely enlarged, making selective or biopsy-based resection insufficient for achieving complete macroscopic disease clearance. The femoral vein was repaired primarily by the orthopedic team. Unexpected peritoneal dissemination involving the transverse colon required partial transverse colectomy with end-to-end anastomosis. The soft-tissue defect was reconstructed using an ipsilateral ALT flap (Figure 3). The total operative time was 14 hours 36 minutes, and estimated blood loss was 870 mL.

Postoperative recovery was largely uneventful. From the patient’s perspective, right lower-limb tightness, pain, and sensory disturbance involving the medial thigh and peripatellar region transiently limited daily activities in the early postoperative period. Ambulation with a walker was initiated at 1 week after surgery, progressing to independent walking by 2 weeks and stair climbing by 3 weeks postoperatively. Transient right-lower-limb edema (CTCAE Grade 2) and mild sensory disturbance (Grade 1) were noted but gradually resolved within 4 months. No major complications (Clavien–Dindo ≥ Grade III) occurred. The patient regained full ambulation by 6 weeks postoperatively.

Final pathology confirmed LGSC involving both ovaries, pelvic and para-aortic lymph nodes, and the right inguinal mass, with additional peritoneal dissemination infiltrating the muscular layer of the transverse colon. Based on these findings, the disease was classified as FIGO stage IVB.

Considering the limited sensitivity of LGSC to conventional chemotherapy and the achievement of complete macroscopic resection, adjuvant endocrine therapy with an aromatase inhibitor was recommended as maintenance treatment; however, the patient declined systemic therapy after being informed that the expected benefit in this clinical setting is limited. From the patient’s perspective, she had experienced some difficulty with right lower-limb movement even before treatment but reported a smooth return to daily activities after surgery, resuming work approximately 4 months postoperatively.

Postoperatively, the patient was followed by the gynecologic oncology team every 2–3 months during the first year, including physical examination and serum tumor marker assessment. Given the rarity of LGSC and the advanced disease stage, contrast-enhanced CT was performed at 2 months postoperatively, followed by surveillance CT every 6 months thereafter. At 13 months after surgery, the patient remains alive with no evidence of disease recurrence. Given the indolent yet persistent nature of LGSC, long-term surveillance remains essential. A detailed timeline of the clinical course is summarized in Supplementary Table 1.

Multidisciplinary collaboration can transcend traditional surgical and oncologic boundaries in advanced gynecologic malignancies. This case demonstrates that coordinated operative planning enables both radical resection and functional preservation in chemotherapy-resistant LGSC, underscoring the value of a framework-based approach to defining surgical limits.