Teratomas of the Brain and Head and Neck

Teratomas of the Brain and Head and Neck Grimme JD, Camacho DLA, Spampinato MV, Castillo M Section of Neuroradiology Department of Radiology University of North Carolina

We present examples of teratomas found in the brain and extracranial head and neck taken from our teaching files, collected over a 10 -year period. Along with the imaging findings we discuss important clinical and pathological information regarding these lesions. Because of the presence of cysts and calcifications, both CT and MRI provide critical information that helps in formulating a differential diagnosis.

Histologic Classification • Mature type: composed of fully differentiated adult-type tissues, absent or low mitoses • Immature type: fetal-type incompletely differentiated tissues • Malignant type: contains cancerous tissues such as sarcomas, carcinomas and other embryonal malignancies

Tumor Markers • Malignant yolk sac endoderm can be an aggressive component of teratomas and these patients may have elevated levels of AFP or beta-HCG in serum and/or CSF • Transcription factors GATA-4 and GATA-6 may also be elevated in mature and immature teratomas

Clinical Features • 90% of teratomas are found below 20 years of age (most: 10 -12 years) • Male-to-female ratio: 2. 5: 1 • 80% occur around region of 3 rd ventricle; thus most symptoms are due to hydrocephalus and increased intracranial pressure

General Imaging Features of Teratomas • Heterogeneous appearance – Presence of fat, cysts (mucous-laden), calcium (bone and chondroid nodules), soft tissues • Enhancing soft tissues – Present in all types of tumors – Enhancement of capsule – Heterogeneous enhancement of soft tissue components

Congenital Teratoma Intracranial teratomas are rare, accounting for 0. 5 -2. 0% of intracranial tumors. They comprise 50% of congenital brain tumors (those presenting in the first 60 days of life). Above: Contrast enhanced CT of congenital teratoma shows a centrally located heterogeneous mass containing cystic/solid components and severe hydrocephalus.

Congenital Teratomas are typically benign tumors containing elements of all 3 germinal layers: ectoderm, mesoderm and endoderm. They develop from embryonic cells which become “misinvolved” during formation of the primitive streak in the 3 rd week of life. Some of these cells become “misenfolded” as intracranial rests of tissue. Above: Axial T 1 (left) and T 2 (right) images of a congenital teratoma (arrows). The mass is centrally located and has a heterogeneous appearance. There is hydrocephalus.

Pineal Teratoma Tissue rests are typically found in the midline, specifically, the pineal, suprasellar and 3 rd ventricle regions. Above: Contrast enhanced CT (left) and pre- (middle) and post-Gd (right) T 1 images. There is peripheral enhancement on CT (arrows) and mild heterogeneous enhancement (arrows) on MRI. Ventricular air was introduced by a ventriculostomy.

Pineal Teratoma Another example of pineal teratoma seen on sagittal T 1 (left), axial post-Gd T 1 (middle) and axial T 2 (right) images. There is heterogeneous signal from cystic and solid components, capsular (arrow) and tumoral enhancement.

Suprasellar Teratoma Differential diagnosis for a T 1 bright and T 2 dark includes aneurysm, dermoid, lipoma and craniopharyngioma. Above: Coronal T 1 (left) and T 2 (right) images of a suprasellar teratoma with considerable fatty contents.

Suprasellar Teratoma Large suprasellar mostly cystic mass (left: T 1 coronal, right: T 2 axial) initially believed to be a craniopharyngioma but proven to be a teratoma.

Suprasellar Teratoma Intracranial teratomas usually manifest in younger children – adult presentation is unusual. Left: Suprasellar teratoma in a child. Axial FLAIR (top left) and T 2 (top right) images show bright lesion. T 1 sagittal images without (bottom left) and with (bottom right) Gd show heterogeneous enhancement of mass.

Suprasellar Teratoma Example of childhood suprasellar teratomas. Axial non-contrast CT (left) and sagittal T 1 image (right) demonstrate fat (arrows) in both lesions.

Intraventricular Teratoma Axial non-contrast CT (left), axial T 2 (middle) and coronal post-Gd T 1 (right) images in intraventricular teratoma. Fat, cysts and calcifications (arrows) are present. The tumor shows central heterogeneous enhancement. Note associated hydrocephalus.

Cerebellar Teratomas are classified by cell/tissue types as mature or immature, and graded histologically from 0 -3, with grade increasing with amount of immature tissues. Grade 0: only mature tissues. Grade 3: large amounts of immature tissues. Above: Cerebellum is an unusual location for teratoma. Axial contrast enhanced CT (left), axial T 2 (middle) and sagittal T 1 (right) images show a heterogeneous mass containing fat (arrows).

Facial Teratoma Differential diagnosis for a facial teratoma includes lymphatic malformation, arteriovenous malformation, hemangioma, neuroblastoma, and dermoid cyst. Above: Axial T 1 pre- (left) and post-Gd (right) images show a heterogeneous cystic mass in the region of the left parotid tail with a heterogeneously enhancing solid component (arrows).

Facial Teratoma Axial T 2 (left), axial T 1 (middle) and sagittal T 1 (left) images of a heterogeneous mass in the left facial region with cystic and solid components, which proved to be a teratoma.

Facial Teratoma the oropharynx or nasopharynx, but may also involve the orbit, temporal fossa, and face. Some teratomas, especially those arising in the nasopharynx, may traverse the skull base and have extensive intracranial extension. Above: Axial CECT of a child with a large exophytic heterogeneous mass, which was originating from the oropharynx. Note the presence of fat adjacent to the coarse calcifications (arrow). C/O Dr. Bernadette Koch

Upper Neck Teratoma Cervical teratomas typically present at birth as firm ovoid masses with palpable cystic areas. Calcifications are seen on plain radiographs in up to 45% of teratomas. Above: Lateral radiograph (left) shows coarse calcifications (arrow) in an anterior upper neck teratoma in a child. Axial CT images (middle and right) of the same patient show macroscopic fat (arrows) in addition to the calcifications.

Upper Neck Teratoma Presenting symptoms of cervical teratomas include respiratory distress, feeding difficulties and torticollis. Axial CECT image of the upper neck shows a large complex mass on the right side with cystic components and heterogeneous enhancement. Note presence of endotracheal tube. C/O Dr. Bernadette Koch

Cervical Teratoma Above: Post-contrast axial CT image (left) and ultrasound image (right) of a cervical teratoma. Note tracheal narrowing and deviation, and presence of calcification seen in both studies (arrows).

Lower Neck Teratomas comprise 9% of head and neck tumors in children. Above: Radiograph (left) and axial CT image (right) of a teratoma arising from the region of the thyroid gland, extending inferiorly into the superior mediastinum. Note leftward tracheal deviation and coarse calcifications within the mass on the CT image (arrow).

Conclusion Teratomas involving the head and neck are rare tumors characteristically involving the midline, nearly always having a heterogeneous appearance and often containing fat and/or calcifications.

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