Successful Laparoscopic Resection of 7 mm Ovarian Mature Cystic Teratoma Associated with Anti-NMDAR Encephalitis

Ovarian and non-ovarian teratomas: a wide spectrum of features

Teratoma is a germ cell tumor (GCT) derived from stem cells of the early embryo and the germ line. Teratoma is the most common neoplasm of the ovaries and is usually diagnosed easily using imagings by detecting fat components. However, there are various histopathological types and the imaging findings differ according to the type. Teratoma usually occurs in the gonads or in the midline due to migration of primordial germ cells during development. The clinical course of teratomas depends on the age of the patient, histological type, and anatomical site. Sometimes teratomas show unusual manifestations, such as mature teratoma without demonstrable fat components, torsion, rupture, growing teratoma syndrome, anti-N-methyl-D-aspartate receptor encephalitis, and autoimmune hemolytic anemia. For all of these reasons, teratomas demonstrate a wide spectrum of imaging features and radiologists should be familiar with these variabilities. The present article aims to introduce a model encompassing types of GCTs based on their developmental potential, and to review several histopathological types in various anatomical sites and unusual manifestations of teratomas, with representative imaging findings.

Magnetic resonance imaging and magnetic resonance spectroscopy in a young male patient with anti-N-methyl-D-aspartate receptor encephalitis and uncommon cerebellar involvement: A case report with review of the literature

We report a case of a 17-year-old man presenting with new onset psychiatric symptoms. Magnetic resonance imaging (MRI) and proton magnetic resonance (MR) spectroscopy revealed some lesions in the right cerebellar hemisphere and ipsilateral cerebellar tonsil suggestive of encephalitis. An extensive workup was negative for both infectious and neoplastic diseases and he was afterward diagnosed with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. This disorder is an autoimmune encephalitis, highly lethal but curable, predominantly found in young female with ovarian teratoma. He received methylprednisolone. His clinical findings gradually improve and he made a complete recovery. Accordingly, repeated brain MRI and proton MR spectroscopy showed a gradual reduction of the lesions; MRI taken six months after starting therapy showed complete resolution of the lesions. Our case shows that, although rare, anti-NMDAR encephalitis should be considered also in young men for whom a rapid onset of psychiatric neurological disorders cannot be explained by more frequent causes. Our report underlines also the usefulness of MRI and proton MR spectroscopic findings in the diagnosis and follow-up of this disease.