congenital teratoma of the neck

Congenital cervical teratoma refers to a teratoma arising in the cervical region. They are thought to account for ~3% of teratomas in childhood/infancy .

Epidemiology

The estimated occurrence in neonates is ~1:20,000-40,000 live births .

Clinical presentation

Most tumors are diagnosed at birth although some cases may be diagnosed in utero .

Complications
  • development of hydrops fetalis if there is significant vascular shunting in utero
  • neonatal airway obstruction

Pathology

Similar to all other teratoid tumors, they comprise of all three germ layers. A teratoma can be either mature or immature. The neck region is the second commonest location for fetal/neonatal teratoid tumors. Neural tissue is the commonest histological component while thyroid tissue is present in ~35% of cases .

Radiographic features

Antenatal ultrasound

Usually seen as a heterogenous solid + cystic mass in and around the fetal neck. They can be multi-loculated and irregular. The presence of calcification is considered a pathognomonic feature although only present in ~50% of cases .

Ancillary sonographic features include:

  • the fetal head may appear hyper-extended to flexed towards a side due to mass effect.
  • polyhydramnios: ~20-40% of cervical teratomas thought to be associated with polyhydramnios, because of esophageal obstruction
MRI

MRI permits a better delineation of the tumor where it is often better appreciated as complex mass arising from the fetal cervical region.

Signal characteristics are heterogenous on both T1 and T2 weighted sequences and highly variable dependent on tumor components. Hence, the mass usually has cystic, tissular and fat components. Calcifications may be detected in ~50% of cases as magnetic susceptibility effects, and is almost pathognomonic for teratoma .

Treatment and prognosis

Although clinically dramatic, they tend to be generally benign tumors histologically. Malignant transformation and metastases are a rare events . They are however associated with a high mortality rate due to there rapid growth and location (particularly with regard to respiratory distress) and require immediate surgical excision. Surgery can be challenging to to its location.

Overall prognosis is variable dependent on several factors such as :

  • size 
  • exact location of lesion
  • tumor growth rate
  • level of tracheal compression

Differential diagnosis

  • fetal goiter: tend to be more homogenous in echotexture and primarily located around the thyroid gland
  • cystic hygroma
  • epignathus: a specific type of teratoma arising from the orofacial region
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