Prognostic significance of nucleolar organizer regions in recurrent pleomorphic adenomas of salivary glands.

Pleomorphic adenoma (PA) is the commonest tumor of salivary glands. It is considered a benign tumor which may recur and rarely metastatize. There are no reliable histological criteria for predicting recurrences of PA. In this paper, Ag-NOR expression, evaluated by means a computer assisted image analysis system, has been tested on 11 cases of PA, their recurrences, 10 non recurrent PA and 5 cases of carcinoma ex PA. Mean AgNOR count, mean AgNOR area and mean AgNOR area/particle were determined in each group. AgNOR count and area did not show any significant differences between recurrent and non recurrent PA. On the contrary, AgNOR area/particle seems to be a useful tool in predicting the clinical behaviour of this lesion.