Real-time contrast-enhanced ultrasound-guided percutaneous biopsy in the diagnosis of ovarian metastasis of gallbladder carcinoma: a case report

Metastatic ovarian cancer often has its origins from various organs and represents approximately 5–15% of all ovarian tumors [4‐6], Krukenberg tumors account for only 1–2% of these metastatic tumors [7] and are often confused with primary ovarian tumors and teratomas. Most patients with gallbladder-derived ovarian malignant tumors have no obvious and specific clinical manifestations, often manifesting with abdominal pain or distension, and only a few patients develop biliary symptoms, such as jaundice [8, 9]. In the patient in our case, only abdominal distension was present as the first symptom, with a pelvic mass palpated during physical examination. The patient also had insidious abdominal pain that was initially considered to be gastritis. Ascites, which usually presents in advanced stages of cancer, was also observed.

No clear differences between primary and metastatic ovarian tumors have been identified from current imaging reports [2]. However, imaging examinations are still valuable in the diagnosis of ovarian metastatic tumors. First, imaging examinations can detect lesions outside the accessory area, thus increasing the probability of the diagnosis of metastatic ovarian cancer. Preoperative US, CT, and PET-CT can also evaluate disease progression and provide guidance for treatment. Second, it has been reported that metastatic ovarian cancer is usually bilateral and more common on the right side [2]. Therefore, in the presence of bilateral tumors, other organs are often examined to determine the presence of a primary malignancy. Metastatic ovarian tumors often present as solid or mixed cystic masses, whereas primary ovarian tumors often present as cystic masses or masses with liquefied necrotic areas [10]. The imaging results in our case revealed a solid primary mass, which is different from the presentation of primary ovarian cancer. However, it appeared as a unilateral ovarian mass, which increased the difficulty of diagnosis. These imaging results were useful for establishing systemic metastasis but lacked specificity. Thus, we performed a real-time CEUS-guided percutaneous biopsy to identify the primary lesion. Percutaneous biopsy is considered conclusive in the diagnosis of cases such as this.

Enhanced ultrasound can clearly delineate tumor blood vessels and necrotic lesions; therefore, we selected contrast-enhanced sites to optimize the positivity rate for percutaneous needle biopsy [11, 12]. CEUS-guided percutaneous biopsy also allowed us to monitor the position of the biopsy needle to avoid damaging the tissue and blood vessels around the mass [13]. After injection of contrast media, the lesion began to strengthen earlier than the uterine muscle wall which showed uneven high enhancement. Large blood vessels were seen in the lesion entering the interior from the side of the mass. A weakly enhancing area inside the mass was observed and considered necrotic or liquefied; therefore, during the puncture process, we avoided the central necrotic area and selected the enhancement area to obtain positive results.

Metastatic ovarian tumors are very difficult to distinguish from primary tumors; however, it is important to distinguish between them because their corresponding treatments are quite different. Differential diagnosis often relies on the patient medical history and immunohistochemical examination. CK7 and CK20 are important markers for distinguishing ovarian tumors [14]. CDX-2 is highly expressed in gallbladder cancer, while it is negative in primary ovarian cancer. SATB2 is highly expressed in the lower epithelial tissues of the digestive tract, and the negative expression of PAX8 can clearly exclude a primary tumor and support a metastatic origin [15].

At present, there is no standard or consensus on the treatment method for metastatic ovarian cancer. Appropriate surgical intervention may prolong survival in patients with primary tumors, but it is not as effective in patients with metastatic tumors that require combination regimens involving radiotherapy or chemotherapy. Moreover, primary ovarian tumors are typically sensitive to platinum, while gallbladder cancer often requires a combination regimen that includes gemcitabine [16]. However, because of the poor prognosis of the patient in our case and the increase in mass size and tumor marker levels despite two courses of gemcitabine and platinum drugs, we switched to combination therapy with durvalumab for six courses, and the treatment results were shown to be effective.