Cervical ectopic thymus in a 9-month-old girl: diagnostic difficulties.

Ectopic cervical location of the thymus is a very rarely diagnosed developmental disorder in children. This anomaly is usually manifested clinically as a neck tumor suggesting lymphadenopathy, which is also differentiated from more frequently occurring cervical cysts, angiomas, or malignant neoplasms. A decisive examination is the histopathologic assessment of the tumor, supported by necessary immunoassays. A diagnostic process is sometimes very difficult and the results are ambiguous; what is more, this process has a decisive impact on the child's future life. Therefore, a histopathologic evaluation performed by 2 independent pathologists should become the standard procedure. We present the case of a 9-month-old girl, in whom, after a difficult diagnostic process, ectopic cervical location of the thymus was diagnosed.