Ectopic thymus presenting as neck mass in a neonate: a case report

Neck masses are rare in newborns and can represent a big challenge for the paediatric surgeons. Different histological types are reported in the recent literature; while 80% of neck masses are benign, the pediatric surgeon is often called upon to assist in the evaluation, diagnosis and treatment. A two-month old baby was evaluated for an asymptomatic left sided cervical mass, presented at birth, which slowly increased in size. A magnetic resonance imaging scan was performed, with evidence of capsulated solid neck mass, lateral to the sternocleidomastoid muscle, not including the major vassel structures of the neck. The patient underwent surgical excision in the criteria to define the histology of the mass. A well capsulated mass was detected at surgery. At histology, an ectopic cervical thymus tissue was reported. The ectopic cervical thymus is an uncommon entity with only 91 cases reported; only nine occurred in infants, two in the neonatal period. According to the authors, in case of enlarging solid neck mass with unclear imaging or clinical data, complete surgical resection is the only and safe procedure to perform.