Role of AgNOR Staining in Histological Grading of Ameloblastoma

Objectives: To compare the different histological variants of ameloblastoma in terms of proliferative activity, using the histochemical method of AgNORs and to grade different variants of ameloblastoma. Methods: It was a cross sectional study of 50 surgical specimens, collected by non probability convenient sampling technique, of ameloblastoma were selected from different hospitals of Lahore (Mayo Hospital, Punjab Dental Hospital, Fatima Memorial Hospital, Services Hospital and Ghurki Hospital). All variants of ameloblastoma (histological variants), all ages and both genders were recruited. Putrefied and unfixed tissues and all the cases underwent decalcification for the presence of bone were excluded from the study. The duration of study was one year from 15-07-2009.to 14-07-2010. All the selected samples were fixed in 10% neutral formalin and processed for initial screening by hematoxylin and eosin in the Department of Pathology, King Edward Medical University, Lahore. These sections were initially reviewed by two pathologists by examination of several hematoxylin and eosin-stained tumour slides (mean, 2.5 slides per tumour; range, 2–8) and a consensus diagnosis was obtained. Results: Overall mean age of the patients was 39.9±15.1 years with a range from 12 to 80 years. In the present study, there were 37 (76%) males and 13 (25%) females. When mean AgNOR values studied among 4 study groups, the mean AgNOR was highest for acanthomatous i.e. 3.15±0.30 and lowest for follicular variant 1.39±0.82. Comparison of mAgNOR was done by using ANOVA and it was calculated that the mean mAgNOR was different in 4 groups, p value <0.001. When association of mAgNOR cutoff value of 3.0 was seen in histological variants, it was observed that the association exists (p=0.003). The cases with mAgNOR >3.0 were only in desmoplastic and acanthomatous groups. Similarly, the association of pAgNOR >5.0 was significant with histological variants (P<0.001). Here all cases of desmoplastic and acanthomatous were having pAgNOR >5.0. Association of size was significant with histological variants (P=0.001). Desmoplastic variants were having +1 and +2 size while acanthomatous were having +2 size only. There were few cases in follicular that had size +1. Similar results were found for association of dispersion with histological variants with p value <0.001. Conclusion: AgNOR staining technique can be useful in histopathological grading of ameloblastoma. Quantitative and qualitative evaluation of silver nitrate staining reflect more malignant potential in acanthomatous and desmoplastic variants than in follicular and plexiform varieties.