Galectin-3 immunodetection may improve cytological diagnosis of occult papillary thyroid carcinoma.

Galectin-3 has been found recently to be neo-expressed in thyroid cancers compared to benign lesions and it could therefore be considered a marker of malignancy. We report the case of a 36-year-old woman with a history of occasional dysphagia and dysphonia first observed in November 2000. Thyroid ultrasound scan revealed two subcentimetric nodules in the right lobe. The larger one underwent ultrasound-guided fine-needle aspiration cytology (FNAC). Due to the nature of the lesion, only a few cells could be collected. Their morphological aspect was suspicious but not conclusive for malignancy, therefore we marked the cells using a monoclonal antibody anti-galectin-3. The cytological suspicions were supported by galectin-3-expressing cells, so the patient was referred to surgery. The final histological diagnosis was conclusive for multifocal occult thyroid papillary carcinomas. We conclude that the galectin-3 immunocytochemical assay should be part of the diagnostic protocol supporting conventional cytology to characterize scanty and/or suspicious cellular smears.