Spontaneous Regression of Posterior Fossa Epidermoid Cyst: Case Report

Background: Epidermoid cysts comprise 0.2 to 1% of all intracranial tumors and are most commonly located in the posterior fossa. The natural history of epidermoid cyst is one of slow growth and, usually, surgical treatment is recommended as the gold standard for symptomatic patients harboring these lesions.

Objective: To report a case of spontaneous resolution of a posterior fossa epidermoid cyst.

Case Report: We present a case of a 46-year-old female with past medical history of rheumatoid arthritis, cirrhosis, hypertension, diabetes mellitus type II, and coronary artery disease, who was first diagnosed with a posterior fossa epidermoid cyst in 2011 ([Figs. 1] and [2]) after presenting with refractory headaches in the neurology clinic. Due to patient’s request for nonoperative management, imaging surveillance with brain MRI was recommended. After experiencing three episodes of aseptic meningitis over the past 2 years, follow-up brain MRI from 2018 ([Fig. 3]) showed spontaneous resolution of the posterior fossa epidermoid cyst. In addition, spine MRI fail to demonstrate drop lesions in the spinal canal ([Fig. 4]).

Conclusion: Although rare, spontaneous resolution of posterior fossa epidermoid cyst may occur, and one should be aware of this possibility when dealing with high-risk surgical patients.

Fig. 1 MRI, diffusion sequence.

Fig. 2 MRI, noncontrast T1 sequence.

Fig. 3 MRI, diffusion sequence.

Fig. 4 Cervicothoracic spine MRI, T2 sequence.