Acinic cell carcinomas of salivary glands histoprognosis. Value of NORs stained with AgNOR technique and examined with semi-automatic image analysis.

Twenty one patients surgically treated for acinar cell salivary gland carcinomas were studied retrospectively. Four cases were excluded from the results because of an inadequate follow-up time (less than 5 years). The rest was classified into two groups: eleven patients with a favorable outcome were still alive without any recurrence after a mean follow-up period greater than 10 years; in six other patients, recurrences and metastases occurred followed by death in four cases. Previously for such tumors a high degree of histological undifferentiation usually gave rise to a poor prognosis, although some exceptions were noted. Thus, in an attempt to find a more reliable prognosis criterion, we evaluated by semi-quantitative image analysis nucleolar organizer regions by means of AgNOR count and mean area in all these cases. Our results significantly correlated with the clinical prognosis: a high count (more than 3) and a small mean area were always found in tumors with an unfavorable outcome whereas lower counts and larger mean areas were found in tumors with a favourable clinical course. Thus, this method showed promise as establishing the prognosis of acinar cell tumours.