Case 17 Answer

Ovarian Dermoid Cyst/ Mature cystic Teratoma

Although there may be some pathologic difference between the two, these terms have become fairly synonymous in the literature.

These are not uncommon and usually seen in 20-30yo females (most common ovarian neoplasm <20yo). They are often asymptomatic, but can be a cause for ovarian torsion, if the clinical history is such.

Look for: Fat, dermoid plug (aka the famous Rokitansky nodule), fat-fluid levels, prominent calcification (ie the “tooth”), and possibly even tufts of hair. Similar things can be seen on US, but make take a little more experience to figure out. Regardless, if you see a mass in a young female with fat or dense calcification, this should come to mind.

Reference: http://radiopaedia.org/articles/mature-cystic-ovarian-teratoma

Nice write up of ovarian lesions: http://www.radiologyassistant.nl/en/p4d85aa9a92bbb#i4dbc80e88db02