Giant Retrorectal Epidermoid Cyst Masquerading as a Perianal Swelling

Figure 1

Perineal epidermoid cyst in a 30-year-old woman. Mass-oriented magnetic resonance imaging showing (a) coronal T2-weighted images (T2WI), and (b) sagittal T2WI. The lesion is indicated with a white arrow. T2WI demonstrated a well-circumscribed homogeneous structure located in the middle of the perianal region and posterior to the rectum (star); the lesion has an intermediate to high signal intensity, suggesting a fluid containing the cystic lesion. In unshown images, the lesion is hypointense relative to surrounding fat tissue on T1WI with no enhancement after gadolinium administration, only slight peripheral rim enhancement.

(a)

(b)