Unilateral polycystic (dysgenetic) disease of the parotid gland.

We report a case of unilateral polycystic disease of the parotid gland. Only eight cases of this disease have previously been published in the English language literature, and seven of them were bilateral. Thus, we are reporting the second case of unilateral involvement. The disease is apparently limited to the parotid gland and to women. Clinically, a fluctuating, long-standing, nontender parotid gland swelling is usually noticed in adulthood. Histologically, there are numerous epithelial-lined cysts, which appear to be derived from intercalated ducts. This disease probably represents a developmental condition.