A 26-year-old woman undergoes CT abdomen for unrelated reasons. The right ovary contains a well-defined cystic lesion measuring 4 cm with a region of fat attenuation, dependent high density material, and a soft tissue nodule projecting into the lumen containing tooth-like calcification. What is the most likely diagnosis?

• A Haemorrhagic corpus luteum cyst
• B Ovarian metastasis from mucinous carcinoma
• C Serous cystadenoma
• D Mature cystic teratoma (dermoid cyst) ✓

Explanation

Mature cystic teratomas characteristically contain fat attenuation fluid, a dependent fat-fluid or fluid-fluid layer from floating sebum, and the Rokitansky protuberance, a mural soft tissue nodule that may contain dystrophic calcification or formed teeth. This triad is virtually diagnostic on CT. Haemorrhagic cysts show high attenuation fluid without fat, serous cystadenomas are simple fluid attenuation, and metastases are solid or mixed masses lacking macroscopic fat and dental elements.

Reference: Grainger and Allison's Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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