An Unusual Perineal Swelling: A Cyst Between the Sphincters

Abstract

Epidermal cysts are very common lesions. Here we present the unusual case of an epidermal cyst occurring between the anal sphincters, presenting as a lump in the perineum. This was successfully excised with careful dissection of the intersphincteric plane. To our knowledge this is the only case of its kind reported in the literature.

Epidermal Inclusion Cyst of the Perianal Region: Report of a Rare Case

“…Squamous cell carcinomas arising from the epidermal cysts are considered to be even rarer [7]. On computed tomography, cysts appear as well-defined surrounded by a capsule; with any contrast enhancement of mural nodule or focal thickening of wall indicates malignant changes [8]. On MRI, the cyst shows low signal intensity on T1-weighted images and intermediate or high signal intensity images on T2-weighted images [5].…”

A Case of Ruptured Perineal Epidermal Cyst

“…The cyst has high signal intensity on fat-saturated images, thin peripheral enhancement, and significant diffusion restriction [1]. On CT, cysts appear as well-defined hypodense lesions with a capsule [3]. Any contrast-enhancing mural nodule or focal thickening of the wall should raise the suspicion of malignancy.…”

“…These can occur in any part of the body but are seen more often in chronic sun-exposed areas [ 1 ]. Presence of epidermal cyst in the perineal region is quite rare [ 1 , 3 - 6 ]. We report a case of a large perineal epidermal cyst with spontaneous rupture treated successfully by surgical excision.…”

Case report of squamous cell cancer arising in perineal epidermal inclusion cyst, presenting as rapidly enlarging and cavitating lesion

“…The location of this lesion, in the central portion of perineal skin, presented a treatment challenge requiring a multidisciplinary team both for diagnosis and for definitive treatment. Neither urology, colorectal or general surgery felt in complete ownership of the condition, unlike cystic lesions that are clearly located in genitalia or anorectal structures [ 5 , 6 ]. The location of malignant degeneration, deep within the cavitating portion of the lesion provided a diagnostic challenge.…”