Fine needle aspiration cytology and immunocytochemistry in a case of intrathoracic thyroid goiter

Fine needle aspiration (FNA) was performed in the case of a patient with an anterior mediastinal mass. Examination of the smears revealed individual and groups of benign nondiagnostic cells. Surgical removal and histologic examination indicated that the mass was a true intrathoracic thyroid goiter. Subsequent immunocytochemical studies on the FNA smears showed thyroglobulin in the cytoplasm of the aspirated cells. The cytologic findings are presented; while not diagnostic of a thyroidal origin in this case, they serve as a reminder of the wide range of cytologic appearances of colloid nodules and goiters. This case will hopefully heighten the awareness of cytologists and other physicians to the consideration of the possibility of intrathoracic goiter in the differential diagnosis of mediastinal lesions seen in fine needle aspirates.