DIAGNOSTIC EVALUATION OF THYROID INVOLVEMENT BY HISTIOCYTOSIS-X

We report the successful diagnosis of thyroid involvement by histiocyt osis X due to accurate evaluation of nuclear medicine results. Methods : A total thyroidectomy specimen from our patient was initially sugges tive of medullary thyroid carcinoma. However, histologic reevaluation was performed on the basis of nuclear medicine findings which were inc ompatible with the original histologic diagnosis. Results: Immunohisto chemical and light microscopy studies were performed to obtain the cor rect diagnosis. Diffuse thyroid involvement by histiocytosis X was dem onstrated. Conclusion: Thyroid scintigraphy was helpful in successfull y diagnosing thyroid involvement by histiocytosis X. Because tracer up take is related to increased cellularity and metabolism, none of these tracers reported here is specific for defining histiocytosis X.