Teaching Case

An 83-year-old female patient with serous borderline ovarian tumour was hospitalised due to abdominal pain, nausea and vomiting. Seven years prior, she was treated with total abdominal hysterectomy and bilateral salpingo-oophorectomy. Unfortunately, two years later she relapsed with disseminated disease. After several unsuccessful courses of chemotherapy, she was now in palliative care.

The patient has small bowel obstruction with dilated and fluid-filled small bowel loops (Fig. 1). The colon is collapsed in almost its entire length and there is a moderate amount of ascites. Encapsulating the majority of the intraabdominal organs, thick and extensive calcified carcinomatosis is seen perihepatic, perisplenic, paracolic, and in the lesser sac, the mesentery, and the lesser pelvis (Figs. 2–4). The thickness measures upwards to 8 cm with attenuation values around 400–500 HU. Minor pleural calcification is also present in the apical pleura on the right side. Small bilateral pulmonary embolisms are suspected due to contrast filling defects (Fig. 5). Apart from three pathologically enlarged lymph nodes (10–14 mm) in the mediastinum, no other nodal involvement is identified above or below the diaphragm. No skeletal metastases are found. Sequelae from the total abdominal hysterectomy with bilateral salpingo-oophorectomy, and a large intrathoracic goitre with primary extension on the left side, are also noted.

Peritoneal calcification is seen in a wide range of diseases such as neoplasms, infections and inflammation. [1,2] Of the neoplasms, ovarian, gastric, and colon cancer are all known to be associated with calcified carcinomatosis. [2–4] Primary neoplasms of the peritoneum, e.g. primary peritoneal carcinoma and malignant mesothelioma, have also demonstrated peritoneal calcification. [1,5] Other potential causes of peritoneal calcification are continuous ambulatory peritoneal dialysis, meconium peritonitis, tuberculosis, and Pneumocystis jirovecii infection. [1,2] Here we present a case of extensive peritoneal (and minor pleural) calcification in a patient with serous borderline ovarian tumour that had previously been radically treated. Borderline ovarian tumours are not classified as true cancers since they lack invasive behaviour. [6] However, these tumours sometimes cause significant morbidity, and also mortality, in spite of an overall 10-year survival of 97% for all tumour stages combined. [7] In our case, widespread peritoneal calcification was a contributing factor for bowel obstruction.

Peritoneal calcification is a rather rare finding on abdominal CT scans, which one study finding only 17 cases out of an approximately 75,000 records. [1] Here, ovarian cancer and peritonitis were found to be the most common causes for peritoneal calcification. A previous case report showed widespread peritoneal calcification in a patient with advanced ovarian cancer. [4] Interestingly, it has been shown that in regard to ovarian cancer, lower histopathological grade and higher disease stage is significantly associated with presence of tumour calcification. [8] This supports our finding of massive peritoneal calcification in a patient with advanced borderline ovarian tumour, since these tumours share genetic alterations with—and are considered precursors to—low-grade ovarian cancers. [7,9]

In contrast to our case, peritoneal calcification is often a subtle finding and the morphology does not clearly correlate with the underlying pathology. Nevertheless, it has been demonstrated that a sheet-like appearance and lack of lymph node calcification suggests a benign aetiology. [1] Other morphological definitions have been used to describe peritoneal calcifications, e.g. diffuse, curvilinear, and nodular; however, there seems to be no strong evidence for any associations between morphology and pathology. [2]

The patient improved spontaneously from her bowel obstruction without surgery and was discharged to further palliative care. Two months later, she passed away with no further diagnostic imaging prior to her death. Underlining the severe disease course, comparison with a CT scan performed 1.5 years prior revealed a marked progression of the peritoneal calcifications despite intermediate chemotherapy (Fig. 6).

Take Home Message / Teaching Points:

• Peritoneal calcification is a rather rare finding with a wide range of causes
• No clear correlation between radiologic morphology and underlying pathology exists

Written informed patient consent for publication has been obtained.