Sclerosing polycystic adenosis of the parotid gland: a case report and literature review

To explore the clinicopathological features, diagnosis, treatment and prognosis of sclerosing polycystic adenosis (SPA) and provide a reference for clinics.

A case of sclerosing polycystic adenosis of the parotid glands was retrospectively analyzed, and the relevant literature was reviewed.

A 57-year-old female patient presented with a tumor, which she had noticed for half a month, on the left side of the lower ear, with occasional paroxysmal numbness and no complaint of other discomfort. Resection of the left submandibular area tumor was performed, and the tumor specimen pathological results showed sclerosing polycystic adenosis of the left parotid gland, with no recurrence after six-months follow-up. Sclerosing polycystic adenosis is rare, occurs in the parotid gland and is characterized by a frequently painless, slow-growing mass of the parotid gland. Imaging examination and fine needle aspiration biopsy can only be used as a reference; the diagnosis must include a pathology examination. Histological manifestations showed that abundant sclerotic collagenous stroma was permeated by ductal and acinar lobules, and cystic dilatation of the duct was accompanied by epithelial hyperplasia and diverse ductal cells. Immunohistochemistry of the ductal and acinar cells showed positive expression of cytokeratin (AE1-3 and CAM5.2) and S100 protein. The ducts filled with hyperplastic and dysplastic epithelium were surrounded by an intact myoepithelial layer that was positive for SMA, p63, and calponin, with a Ki-67 index less than 3%. Treatment comprised mainly surgical resection, with a good prognosis. However, one-third of cases relapse: low-grade malignant tumors may occur, with at least one report of invasive cancer.

Sclerosing polycystic adenosis of the salivary gland is rare and has a good prognosis, but patients may relapse easily after surgery. The diagnosis depends primarily on pathological examination. The main treatment is surgical resection, the prognosis is good, and follow-up should be strengthened after surgery.