Mature cystic teratoma of the neck misdiagnosed at cystic hygroma; Case report.

Background: Teratomas arise from primordial germ cells which arrest during its migration from the hindgut allantois the gonads during the first weeks of gestational life, they may occur in both gonadal and extra-gonadal locations. They occur in 1/40,000 live births. The most common anatomical locations are the sacro-coccygeal region and the ovary, neck teratomas constituted about 1.5%. Malignant transformation has been reported.

Case Presentation: A 2-year-old boy presented with a gradually enlarging mass in the left side of the neck causing stridor and difficulties in respiration especially during sleep, the parents noticed difficulties during swallowing. The mass was misdiagnosed as cystic hygroma and the patient underwent 2 sessions of sclerotherapy with no improvement. Clinical examination showed a large mass in the left side of the neck which was multilobulated causing tracheal shift to the opposite side. There were no signs of inflammations over the mass. CT-scan showed evidence of enhancing multi-cystic lesion with multiple flecks of calcification. Complete surgical resection was done successfully and the histopathological study of the mass showed mature elements of ectodermal, mesodermal, and ectodermal germinal layers which was consistent with mature cystic teratoma. The follow up showed no postoperative complications.

Conclusion: Mature cystic teratoma of the neck is very rare and may be difficult to be differentiated both clinically and radiologically from other neck masses. The accurate diagnosis must be made before any kind of treatment is started. Complete surgical resection is the main management option and required to decrease the recurrence.