Asymptomatic neck mass and normal variations of the thymus in children: A report of two cases from a tertiary hospital in Riyadh, Saudi Arabia.

The pathogenesis of cervical extension of the thymus has been postulated to be incomplete descent of the thymus in the midline of the neck, which is considered normal in children. The thymus normally extends to the neck in approximately two-thirds of children. Ectopic thymus mainly occurs in 1%-13% of the younger population. In this study, we report two cases of asymptomatic neck swelling, one due to cervical extension of the thymus and the other due to a right submandibular ectopic thymus. None of the patients required any intervention. Recurrent suprasternal swelling in children that becomes more pronounced during coughing/crying or Valsalva maneuvers can be more accurately diagnosed using neck ultrasonography and/or magnetic resonance imaging.