1. ¹Departments of Reproduction and Ageing, University of Pisa, Pisa 56024, Italy
2. ²Department of Oncology, Divisions of Surgical, Molecular and Ultrastructural Pathology, University of Pisa, Pisa 56024, Italy
3. ³Institute of Clinical Physiology, CNR, Pisa Italy
4. ⁴Department of Internal Medicine, University of Pisa, Pisa 56024, Italy
5. ⁵Department of Experimental Medicine and Endocrinology, University La Sapienza, and Ospedale San Pietro Fatebenefratelli, Associazione Fatebenefratelli per la Ricerca, Rome 00158 Italy
6. ⁶Department of Pathology, St Andrea University Hospital, Via di Grottarossa 1035, Rome 00158, Italy
7. ⁷Cellular and Molecular Tumor Pathology Laboratory, Cancer Center Karolinska, CCK R8:04, Karolinska Hospital, Stockholm S-17176, Sweden

Correspondence: Dr A Bartolazzi, Department of Pathology, St Andrea University Hospital, Via di Grottarossa 1035, Rome 00158, Italy. E-mail: Armando.Bartolazzi@ki.se

Received 3 April 2006; Revised 25 May 2006; Accepted 25 May 2006; Published online 27 June 2006.

Abstract

Thyroid fine-needle aspiration biopsy (FNA)-cytology is widely used for the preoperative characterisation of thyroid nodules but this task is difficult for follicular lesions, which often remain undefined. We propose a strategy for improving the preoperative characterisation of selected follicular thyroid proliferations, which is based on large needle aspiration biopsy (LNAB) and galectin-3 expression analysis. Eighty-five thyroid specimens were obtained by LNAB (20-gauge needles) from thyroid nodules with indeterminate follicular FNA-cytology. Aspirated material was processed as a tissue microbiopsy to obtain cell blocks for both cyto/histo-morphological evaluation and galectin-3 expression analysis, by using a purified monoclonal antibody to galectin-3 and a biotin-free immunoperoxidase staining method. Preoperative diagnosis was compared to the final histology. LNAB and cell-block technique allow a preliminary distinction between nodules with a homogeneous microfollicular/trabecular structure, as frequently observed in tumours, and lesions with mixed normo–micro–macrofollicular architecture, as observed in goitre. Furthermore, LNAB provides optimal substrates for galectin-3 expression analysis. Among 85 cases tested, 14 galectin-3-positive cases were discovered preoperatively (11 thyroid cancers and three adenomas confirmed at the final histology), whereas galectin-3-negative cases were 71 (one carcinoma and 70 benign proliferations at the final histology). Sensitivity, specificity and diagnostic accuracy of this integrated morphologic and phenotypic diagnostic approach were 91.6, 97.2 and 95.3%, respectively. In conclusion, LNAB plus galectin-3 expression analysis when applied preoperatively to selected thyroid nodules candidate to surgery can potentially reduce unnecessary thyroid resections.