Giant Arachnoid Cyst Presenting With Transient Facial Paresthesia: A Case Report

TL;DR

A large brain cyst was found in a man with temporary facial numbness, showing that big cysts don't always need treatment.

Contribution

Highlights that giant arachnoid cysts can cause minor, temporary symptoms without requiring intervention.

Findings

The patient's symptoms resolved on their own without treatment.

Large arachnoid cysts may not always lead to significant neurological issues.

Clinical decisions should focus on symptoms, not just imaging results.

Abstract

Arachnoid cysts are benign, cerebrospinal fluid-filled lesions that are frequently discovered incidentally on neuroimaging. Although most remain asymptomatic, large cysts may occasionally be associated with neurological symptoms due to mass effect or compression of adjacent structures.

We report the case of a 61-year-old man who presented with transient numbness of the left side of the face. Brain computed tomography (CT) revealed a large right parieto-occipital arachnoid cyst with cerebrospinal fluid-like density, smooth margins, and thinning of the overlying calvaria, consistent with a long-standing lesion. The patient’s symptoms resolved spontaneously, and no additional neurological deficits were observed during follow-up.

This case illustrates the frequent dissociation between the striking radiologic appearance of giant arachnoid cysts and their limited clinical expression. Despite its size, the lesion was associated only with mild and self-limited symptoms, supporting a conservative management approach.

Giant arachnoid cysts may remain clinically silent or present with transient symptoms. Clinical management should be guided by symptom severity and evolution rather than imaging findings alone in order to avoid unnecessary interventions.

Figures