L A Orloff1, E A Weymuller, M J Flaherty. 1. Department of Otolaryngology/Head and Neck Surgery, University of Washington School of Medicine, Seattle, USA.
Abstract
BACKGROUND: Immunohistochemical methods and aspiration cytology are used with increasing frequency in the diagnosis of head and neck histopathology. Magnetic resonance imaging is also gaining popularity as a diagnostic tool. METHODS: We report a case of papillary thyroid carcinoma which was initially misdiagnosed as malignant melanoma due to several confounding diagnostic test results. RESULTS: False-positive immunostaining of a cytologic preparation with a commercial preparation of HMB45 melanoma stain and characteristic MRI findings contributed to the erroneous diagnosis of malignant melanoma. CONCLUSIONS: Potential pitfalls in test interpretation are discussed, and recommendations for the judicious use of immunostaining, MRI, and other diagnostic studies are presented.
BACKGROUND: Immunohistochemical methods and aspiration cytology are used with increasing frequency in the diagnosis of head and neck histopathology. Magnetic resonance imaging is also gaining popularity as a diagnostic tool. METHODS: We report a case of papillary thyroid carcinoma which was initially misdiagnosed as malignant melanoma due to several confounding diagnostic test results. RESULTS: False-positive immunostaining of a cytologic preparation with a commercial preparation of HMB45 melanoma stain and characteristic MRI findings contributed to the erroneous diagnosis of malignant melanoma. CONCLUSIONS: Potential pitfalls in test interpretation are discussed, and recommendations for the judicious use of immunostaining, MRI, and other diagnostic studies are presented.