There may be associated tenderness, pain, and if in the parotid, seventh nerve paralysis. ACC is associated with a high incidence of neural invasion. Although an indolent tumor, ACC shows persistent and recurrent growth, with late onset metastases. This is reflected by the good five year survival rate, but the poor 10 - 20 year survival rates. Koss describes ACC as having a characteristic cytologic presentation.
Tumor cells are small with small nuclei and readily visible but small nucleoli.
There is no significant variability in nuclear size or shape. Some cell clusters show cores of homogenous hyaline material. Occasionally very large fragments of tumor tissue may be aspirated and these may have a lobulated appearance. Some smears are accompanied by numerous dispersed cells that may form rosette-like structures. If the tumor is poorly differentiated, smears may lack hyaline globules or tissue fragments and while the precise determination of the tumor type may then be difficult, cytological features of malignancy allow the diagnosis of a malignant tumor.