Ectopic cervical thymus associated with infant death: 2 case reports and literature review.

An ectopic cervical thymus is a rare congenital anomaly that can be located anywhere along the developmental pathway of thymic descent. Most lesions manifest as a cystic mass and have an indolent course. Two fatal cases associated with ectopic cervical thymus in the form of a solid mass are presented in conjunction with a review of the clinicopathological characteristics of the solid form. This report emphasizes the importance of considering a diagnosis of ectopic cervical thymus in infants with neck masses, with or without obstructive symptoms, to prevent possibly fatal outcomes.