Case presentation

A woman in her seventies presented with progressive abdominal distension, early satiety, vomiting, bilateral lower limb edema, and back pain. Imaging demonstrated a large heterogeneous adnexal mass with massive ascites, and laboratory evaluation revealed elevated cancer antigen (CA)-125 and estradiol levels.

She was referred to a tertiary oncology center with suspected primary gynecologic malignancy. Her medical history included obesity, dyslipidemia, hypertension, and a recently diagnosed pulmonary embolism. She had no previous surgery and was a lifelong non-smoker. Her gynecologic history included one full-term vaginal delivery and natural menopause at 52 years of age. She lived independently, with regular family support.

She presented with a four-month history of progressive abdominal distension, early satiety, vomiting controlled with antiemetics, bilateral lower limb edema, and mild dorsal pain. During a previous admission to a secondary hospital, contrast-enhanced computed tomography (CECT) of the abdomen and pelvis had shown abundant abdominopelvic ascites, loculated hemorrhagic collections, and a large heterogeneous solid-cystic mass measuring approximately 26 × 16 cm (Figure 1).

Figure 1: Contrast-enhanced computed tomography (CT) of the abdomen and pelvisDemonstrates a large heterogeneous adnexal mass (red circle). (A) Coronal CT image shows the lesion occupying the pelvis with associated ascitic fluid (yellow arrow); (B) Sagittal CT image confirms the extent of the mass, with ascitic fluid and the uterus (outlined by the green dashed line).

No suspicious lymphadenopathy or distant metastases were identified. Serum CA-125 was elevated (301 U/mL; reference range: 0-35 U/mL) at the initial patient evaluation.

Pelvic magnetic resonance imaging confirmed a bulky heterogeneous adnexal mass measuring more than 25 cm, with areas suggestive of internal hemorrhage and marked mass effect on adjacent pelvic organs (Figure 2).

Figure 2: Pelvic magnetic resonance imaging (MRI)Demonstrates a large heterogeneous adnexal mass with cystic and solid components. (A) Coronal T2-weighted image shows the lesion (yellow circle) with hyperintense cystic areas and mild ascites. (B) Sagittal T1-weighted image confirms the large heterogeneous mass (yellow circle), with the uterus outlined by the green dashed line.

Imaging did not allow reliable characterization of tumor subtype. At presentation to our center, the patient had an Eastern Cooperative Oncology Group (ECOG) performance status [13] of one. Abdominal examination revealed marked distension, a large central mass extending above the umbilicus, and clinical signs of ascites.

Given the uncertain origin and histological nature of the lesion, a transvaginal ultrasound-guided biopsy was performed as a minimally invasive diagnostic procedure. Histology showed a poorly differentiated neoplasm with biphenotypic expression of epithelial and mesenchymal markers, but no definitive diagnosis could be established. A subsequent image-guided core biopsy demonstrated a spindle-cell neoplasm with smooth muscle differentiation, low proliferative activity, and minimal nuclear pleomorphism, raising the differential diagnosis of leiomyoma versus leiomyosarcoma.

Because of the atypical presentation and inconclusive pathology, an extended tumor marker and hormonal panel was obtained. CA-125 remained elevated, whereas carcinoembryonic antigen (CEA), lactate dehydrogenase (LDH), alpha-fetoprotein (AFP), and beta-human chorionic gonadotropin (β-hCG) were within normal limits. Hormonal assessment revealed markedly elevated estradiol and mildly increased testosterone levels, supporting the possibility of a hormonally active sex cord-stromal tumor.

The case was discussed at the multidisciplinary gynecologic tumor board, and surgical exploration was recommended. Repeat thoracoabdominopelvic CT showed stable ascites and peritoneal thickening, without distant metastatic disease.

Exploratory laparotomy revealed marked abdominal distension due to ascites, large bilateral adnexal masses measuring approximately 35 × 25 cm, adhesions to the anterior and lateral abdominal wall and sacral curvature, an omental mass adherent to the small and large bowel, an abdominal wall tumor involving the umbilicus, and scattered peritoneal carcinomatosis in the pouch of Douglas. Cytoreductive surgery included drainage of approximately nine liters of ascitic fluid, extensive adhesiolysis, total hysterectomy with bilateral salpingo-oophorectomy, peritonectomy of the pouch of Douglas, excision of the abdominal wall tumor including the umbilicus, and fulguration of small peritoneal implants. Complete macroscopic resection was not feasible because of unresectable adherent disease and the anticipated risk of severe morbidity. The final surgical outcome was therefore classified as R2, with residual macroscopic disease greater than 1 cm.

Histopathological evaluation was complex, and the specimen was referred for expert review at a reference pathology center. The final diagnosis was an ovarian sex cord-stromal tumor most consistent with a poorly differentiated Sertoli-Leydig cell tumor with estradiol hyperproduction, staged as pT3c cN0 cM0, International Federation of Gynecology and Obstetrics (FIGO) stage IIIC. Histopathological and immunohistochemical findings are shown in Figures 3, 4.

Figure 3: Hematoxylin and eosin-stained sections of the ovarian tumor(A) Densely cellular tumor proliferation; (B) Highly vascularized tumor areas; (C) Higher magnification demonstrating oval-to-spindle-shaped tumor cells with moderate nuclear pleomorphism.

Figure 4: Immunohistochemical staining of the ovarian tumor(A) Diffuse cytoplasmic positivity for cytokeratin 19 (CK19); (B) Strong diffuse immunoreactivity for broad-spectrum cytokeratins anti-epithelial (AE)1/AE3, supporting epithelial differentiation.

Molecular testing for Forkhead box L2 (FOXL2) and Dicer 1, ribonuclease III (DICER1) variants was requested, but suboptimal sample quality rendered the analysis invalid. DICER1 alterations have been reported particularly in moderately and poorly differentiated Sertoli-Leydig cell tumors, supporting their relevance in the molecular characterization of this entity.

In view of advanced disease, residual tumor, and the risk of clinical deterioration, systemic therapy was proposed. Considering the patient’s age, comorbidities, and performance status, carboplatin-paclitaxel was selected instead of a cisplatin-based regimen. She received carboplatin area under the curve (AUC) four and paclitaxel at 85% of the standard dose, aiming to balance disease control and tolerability. Supportive care included analgesia, antiemetics, gastric protection, nutritional counseling, and anticoagulation.

The patient completed nine cycles of carboplatin-paclitaxel. Postoperative CT performed approximately three months after surgery showed a large loculated cystic mass in the lesser sac, persistent moderate ascites, and diffuse peritoneal nodularity consistent with peritoneal carcinomatosis, without distant metastases. Tumor markers were normal, but serum estradiol remained markedly elevated.

Approximately one year after surgery, CT demonstrated persistent large-volume ascites, a complex loculated cystic lesion, and worsening peritoneal carcinomatosis, including implants adherent to the abdominal wall and paracolic gutter. Biopsy of a new abdominal wall lesion confirmed recurrent poorly differentiated Sertoli-Leydig cell tumor involving the linea alba. Further image-guided biopsy of intra-abdominal lesions was considered to better characterize progressive disease, but it was not feasible because of extensive malignant ascites and the absence of a safely accessible solid target.

The patient required repeated admissions for symptom control, including large-volume paracenteses of hemorrhagic ascites. Despite supportive measures, her condition deteriorated, with progressive abdominal distension, early satiety, abdominal colic, and wheelchair dependence. Her performance status declined to ECOG two, and laboratory evaluation showed anemia, renal impairment, electrolyte disturbances, and elevated LDH.

After discussion with the patient and family, weekly paclitaxel was proposed as palliative second-line therapy. Best supportive care alone was also discussed as an appropriate option, but the patient and relatives preferred to proceed with chemotherapy. Her clinical condition rapidly deteriorated after treatment initiation, and she died approximately one week later.