Teaching Case

The authors describe the case of a 52 year old woman affected by gastric cancer 6 years previously, that was referred to our institution for recent weight loss and lower back pain. In the imaging evaluation bilateral solid adnexal masses were found together with a small volume of ascitic fluid and several lytic bone lesions.

The patient was referred to our institution’s surgery department with complaints of lower back pain and recent weight loss (8 kg over the last 3 months). The physical examination was unremarkable. The patient had been affected by gastric cancer 6 years previously and underwent subsequent total gastrectomy. An abdominal and pelvic ultrasonography (US) was requested and demonstrated bilateral solid ovarian masses, measuring 84 mm on the right and 48 mm on the left, with well defined margins and an irregular echo texture, with both hypo and hyperechoic areas. No cystic component was present and a small volume of free fluid was found in the pouch of Douglas and surrounding the pelvic intestinal loops. In face of these findings a computerized tomography (CT) of the abdomen and pelvis was performed, with oral and intravenous contrast material, confirming the US findings (bilateral solid adnexal masses and a small volume of ascitic fluid in the pelvic cavity). Intravenous administration of iodinated contrast material allowed a further characterization of the ovarian tumours, demonstrating a strong an heterogeneous pattern of enhancement. Also several lytic bone lesions were found in the lower lumbar vertebrae and iliac bones, suggestive of metastatic origin.

In 1896 Krukenberg described what he presumed was a new type of primary ovarian neoplasm. The true metastatic nature of this lesion was established six years later. Some 5 – 10% of all ovarian malignant lesions are regarded as metastatic. Of them approximately 50% are Krukenberg tumours, which have well defined histologic characteristics (carcinoma with signet-ring cells and stroma with sarcomatoid reaction). Krukenberg tumor is secondary to a neoplastic process in the gastrointestinal tract. The stomach is the commonest primary site (2% of all women with gastric cancer develop ovarian metastasis), followed by the colon. Gallbladder, biliary ducts and appendix can also be the source of the primary neoplasm. In a variable percentage the primary tumour remains unknown. The incidence of Krukenberg tumor is approximately 0.16/100.000 per year, and at presentation the adnexal tumours tends to be large, bilateral and associated with ascites. The time from diagnosis of the primary neoplasm to the development of ovarian metastasis is variable, from several months to more than 10 years, and can even precede the diagnosis in 20% of the patients, which are usually in the fifth or sixth decade of life. At US Krukenberg tumor typically present as bilateral, solid ovarian masses, with clear well defined margins. An irregular hyperechoic solid pattern and moth eaten like cyst formation are also characteristic, allowing with some confidence to distinguish these lesions from primary ovarian neoplasms. A relatively prominent vascular signal along the wall of the intramural cysts in a predominantly solid ovarian mass has also been described as a suggestive finding. Ascites is also frequent at presentation. CT shows solid masses and frequently intratumoral cysts, with strong contrast enhancement, a pattern that allows a differential diagnosis with primary ovarian cancer, where such a marked enhancement of the cyst walls is absent. At MR a hypointense solid component within an ovarian mass on T2-weighted images is characteristic, although not specific, finding for Krukenberg tumor, especially when adnexal masses are bilateral, have sharp margins and an oval configuration. The pattern of enhancement of the cyst wall component is similar to that described for CT.