Gardner Syndrome is a rare disease with clinical manifestations of familial intestinal polyposis with osteomas. Cutaneous and subcutaneous lesions are common and epidermoid cyst is a characteristic dermatologic finding. This case report presents a novel finding of an intracranial epidermoid situated in the fourth ventricle in a patient with Gardner Syndrome. This intracranial epidermoid has been followed with sequential magnetic resonance imaging (MRI) for 10 years with progressive growth of the lesion. This suggests the conservative management is an option in patients with an enlarging epidermoid cyst in the fourth ventricle.
Plain language summary:

Non-operative treatment of a cyst in the brain in a syndrome called Gardner syndrome. What is Gardner syndrome? Gardner syndrome is a rare disease and form of familial adenomatous polyposis (FAP) that is characterized by multiple small growths of cells (polyps) in the colon and various types of tumors, both noncancerous (benign) and cancerous (malignant). It is caused by changes (mutations) in the APC gene. Abnormal changes on the skin and under the skin are common as well as growths called epidermoid cysts. The cysts develop when cells that are meant to become skin, hair, and nails (epithelial cells) are trapped among the cells that form the brain. Epidermoid brain cysts may be diagnosed by magnetic resonance imaging (MRI) and computerized tomography (CT) scans. Typical treatment usually involves surgery. What was the aim of this case report? To present a different management strategy for patients with Gardner Syndrome with epidermoid brain cysts. How was this patient treated? This patient is the first patient with Gardner Syndrome with a very rare epidermoid brain cyst reported to be treated in a conservative manner.The patient was monitored for 10 years with regular MRI scans and the cyst continued to grow over this time.Despite this growth the patient has shown no signs of a buildup of fluid in the cavities deep within the brain (called hydrocephalus).The patient experienced nonfocal headaches, which were relieved with medication so doctors decided not to surgically remove the cyst. Why is this case important? Conservative management of epidermoid brain cysts in Gardner patients has not been reported before. This case report shows that conservative management may be an alternative option for patients with a growing epidermoid cyst in the fourth ventricle of the brain. Conservative treatment is designed to avoid invasive treatments or surgery and provides a different option for patients who are unable to have surgery.