Thymic ultrasound II. Diagnosis of aberrant cervical thymus

Background. The aberrant cervical thymus is an uncommon entity to be consid ered in the differential diagnosis of neck masses in children, so a preoper ative diagnosis has rarely been made. Objective. The purpose of this study was to assess the ultrasound features of aberrant cervical thymus and determine if recognition of the previously described unique intrathymic echo pattern allows us to make a specific diag nosis. Materials and methods. We present four patients with an aberrant cervical t hymus and one patient with a cervical thymic cyst. All five patients had ul trasound, which was evaluated with special attention to the detailed echo p attern of the mass. In two patients, the mass was surgically removed. Four patients had MRI, which was evaluated. Medical records were reviewed. Results. In all cases, the mass was painless and nontender. All occurred in the expected path of the thymopharyngeal duct. In four patients, ultrasoun d demonstrated multiple echogenic linear structures and foci previously des cribed as characteristic echo pattern of normal thymic tissue. In one patie nt, ultrasound showed a large cystic mass and echogenic solid component sup eriorly with a characteristic echo pattern of normal thymus. Conclusions. The ultrasound appearance of thymic tissue is unique, allowing a specific diagnosis of aberrant cervical thymus, Biopsy or other imaging is probably not indicated when it presents with typical clinical features.