AgNOR Counts in Differential Diagnosis of Parathyroid Adenoma and Hyperplasia in Preoperative Cytologic Smears

Abstract

Objective. Minimally invasive surgery is the method of choice in the management of hyperparathyroidism caused by parathyroid adenoma, whereas in case of parathyroid hyperplasia radical operative procedure is necessary to prevent recurrence of the disease. The aim of the study was to investigate morphological and cytochemical parameters differentiating parathyroid adenoma from parathyroid hyperplasia in cytologic smears in preoperative work-up of patients with hyperparathyroidism. Methods. Fifty parathyroid cytologic smears, preoperatively obtained by ultrasound-guided aspiration biopsy were analyzed. Fifty parathyroid cell nuclei per smear were analyzed, and the number of nucleolar organizer region (AgNOR) determined using SFORM software (Vamstec, Zagreb). The results obtained were compared with histopathology findings. Results. The values of nuclear size parameters obtained by morphometric measurement revealed cells with larger nuclei and greater nuclear size diversity to be found in parathyroid adenoma, thus enabling differentiation of parathyroid hyperplasia from parathyroid adenoma in many cases. However, due to overlapping of borderline values, the possibility of error was tried to reduce by determining AgNOR count and structure. The results obtained showed that neither AgNOR count, nor AgNOR classification into individual AgNOR, AgNOR clusters and annular AgNOR had any role in differentiating parathyroid hyperplasia and parathyroid adenoma. Conclusion. Study results showed that AgNOR count and structure cannot help in determining more clearly the border between parathyroid adenoma and hyperplasia in cytologic smears. Key words : AgNORs, parathyroid adenoma, parathyroid hyperplasia