CORRELATION BETWEEN ARGYROPHILIC NUCLEOLAR ORGANIZER REGION (AGNOR) COUNTS AND HISTOLOGIC GRADES WITH RESPECT TO BIOLOGIC BEHAVIOR OF SALIVARY ADENOID CYSTIC CARCINOMA

The quantification of argyrophilic nucleolar organizer regions (AgNOR) was performed in 34 cases of adenoid cystic carcinoma (ACC) to determ ine (1) whether AgNOR count correlates with its different histologic g rades pertinent to prognosis, and (2) whether AgNOR counts can offer a ny additional prognostic advantage over histologic grading. According to SZANTO ef al.'s histologic grading criteria (4), 12 cases were Grad e 1, 7 cases Grade 2, and 15 were Grade 3. Patients were divided into 20 favorable cases (without metastases) and 14 unfavorable cases (with metastases). Although most Grade 3 tumors had high AgNOR counts (grea ter than or equal to 4) and Grade 1 tumors with low (< 4) AgNOR counts outnumbered those with high AgNOR counts, considerable overlap of AgN OR values in different grades was observed. However, all unfavorable c ases had high AgNOR counts regardless of their histologic grades, sugg esting that the metabolic alterations associated with the malignancy l evel of ACC may partly be portrayed by the AgNOR count, irrespective o f the histologic appearance. Cumulative survival rates of Grade 1 tumo rs and of tumors with low AgNOR counts were better than those of Grade 3 tumors and those with high AgNOR counts. Within the limited number of cases in this series the AgNOR count exhibits a potential for ident ifying some aggressive ACCs that cannot be detected by histology alone .