OBJECTIVE: Thymic diseases can arise from remnants of thymic tissues along the path of fetal descent and may simulate thyroid tumors or lymphadenopathy. MATERIALS AND METHODS: We present two patients with a cervical mass arising from the cervical thymus that was caused by incomplete descent of the thymus into the mediastinum. RESULTS: In one patient a cervical mass was surgically confirmed to be a cervical thymoma, which simulated a thyroid cancer on CT and 201Tl-scintigraphy. In another patient, cervical thymic hyperplasia arising from an incompletely descended thymus was surgically confirmed. The isointensity between the cervical mass and an enlarged mediastinal thymus was recognized on MRI. CONCLUSION: If a cervical mass is located in the region of the lower pole of the thyroid or if there is a connection or the same intensity between the cervical mass and the mediastinal thymus on MRI, a diagnosis of a cervical mass of thymic origin should be considered.
OBJECTIVE: Thymic diseases can arise from remnants of thymic tissues along the path of fetal descent and may simulate thyroid tumors or lymphadenopathy. MATERIALS AND METHODS: We present two patients with a cervical mass arising from the cervical thymus that was caused by incomplete descent of the thymus into the mediastinum. RESULTS: In one patient a cervical mass was surgically confirmed to be a cervical thymoma, which simulated a thyroid cancer on CT and 201Tl-scintigraphy. In another patient, cervical thymic hyperplasia arising from an incompletely descended thymus was surgically confirmed. The isointensity between the cervical mass and an enlarged mediastinal thymus was recognized on MRI. CONCLUSION: If a cervical mass is located in the region of the lower pole of the thyroid or if there is a connection or the same intensity between the cervical mass and the mediastinal thymus on MRI, a diagnosis of a cervical mass of thymic origin should be considered.