Paediatric Radiology

Case  13 :  
Pediatric Radiology
A 3-year-old female presents with a neck mass. What is the diagnosis?
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Fig 1 Fig 2
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Scan reveals calcification with fat contents within the neck mass.

Teratomas of the neck, nasopharynx, pharynx, and oral cavity are usually large, bulky masses that are clearly evident and recognized at birth. Many of these are diagnosed at routine prenatal ultrasound examinations. The primary differential diagnostic considerations for a large neck mass, either in a fetus or an infant, include cystic hygroma and congenital cysts of branchial cleft or thyroglossal duct origin.
The majority of extragonadal teratomas, including those of the head and neck, manifest during childhood, although they represent less than 5% of all pediatric neoplasms. Some authors have reported a bimodal distribution for craniofacial teratomas, with the biologically and histologically benign lesions seen in infants and children and malignant teratomas seen in older children and adults. In a review of the literature, Jordan and Gauderer reported that only 10.6% of all cervical teratomas occurred in adults but 69% were malignant, compared with only 2.5% that were malignant in patients under 18 years of age.
A teratoma can be suspected when a multiloculated lesion with focal areas of low attenuation and high signal intensity (representing lipid) is seen on CT and T1-weighted MR images, respectively. Radiologically evident lipid may be scattered throughout the mass, rather than forming a single, large collection or fat-fluid level that might suggest a dermoid inclusion cyst. The developmental cysts of the branchial cleft and thyroglossal duct are also more often unilocular, with only a thin rim of enhancement, and do not contain fat. Occasionally, these cysts appear septated and therefore mimic a multiloculated teratoma. Thyroglossal duct cysts tend to be oblong or roughly tubular, oriented vertically along the path of the normal embryologic migration of those structures. Within the tongue, they are usually in the posterior one-third or the base. The lingual teratoma illustrated in resembles a thyroglossal duct cyst, but it is multilocular and somewhat more anterior within the tongue muscles than the embryologic course of the thyroglossal duct.

Dr. Ashok Raghavan, Manipal Hospital, Bangalore