Disseminated xanthogranulomatous oophoritis mimicking malignancy on 18F-fluorodeoxyglucose positron emission tomography/computed tomography

Introduction: Objectives

1. To evaluate the clinicopathological features of xanthogranulomatous oophoritis.

2. To highlight the indications and characteristics of positron emission tomography/computed tomography in xanthogranulomatous oophoritis for a correct diagnosis.

Background

Xanthogranulomatous process is a rare chronic inflammation characterized by mucosa infiltration by inflammatory granulation tissue and foam tissue cells. It usually occurs in the gallbladder and kidneys, but rarely, it is also observed in the female reproductive system. This disease can develop in adult women at all ages. The common clinical symptoms include fatigue, abdominal pain, fever, and irregular vaginal bleeding.

Methods: This study reports a case of a 54-year-old woman presenting with abdominal pain. Ultrasonography suggested bilateral ovarian masses with suspected malignancy, and positron emission tomography/computed tomography (PET/CT) was recommended.

Results: Bilateral ovarian masses and abdominal lesions with high ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) avidity were observed. The liver and peritoneum are invaded by lesions. A malignant ovarian tumor with peritoneal metastases was suspected. However, the histopathology of the resected lesion revealed a xanthogranulomatous oophoritis of the ovary. The imaging findings of the ovary revealed a mainly cystic solid mass, with negative CT values in the cystic part (−12 to −4 HU), indicating the presence of lipid components. Histopathologically, the mass was composed of foam cells containing lipid components. The lipid density was measured due to its prompting significance in disease diagnosis. The enhanced scan continuously enhanced the cyst wall of the lesion, and few small cystic lesions without enhancement were observed as yellow granulomatous nodules in the thick wall.

Conclusions: Xanthogranulomatous oophoritis disseminated to the peritoneum can be easily misdiagnosed as a malignant tumor. Although the correct diagnosis is obtained primarily through histopathology, the preoperative diagnosis of xanthogranulomatous oophoritis can prevent radical surgery.

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