Supplementary Material for: The Cystic Sponge Anus

Introduction:
A peculiar spongy appearance of the perianal skin was observed a patient who underwent wide excision surgery for inguinal and gluteal Hidradenitis Suppurativa (HS).

Case Presentation:
This peculiar appearance was observed in a 62 year old male patient. It included multiple orifices and cavities forming the spongy aspect of the perianal skin with multiple cysts and giant comedones. The perianal lesions were asymptomatic and the patient had never received any perianal treatment for the comedones or cysts. Histopathology was performed and demonstrated dilated hair follicles with flaky keratin and loose hair shafts in the center. The spongy appearance was most likely the result of spontaneous shedding of the cystic contents.

Conclusion:
We suspect that the ‘Cystic Sponge Anus’ might be associated with HS, smoking, the male gender, and may yet be another expression of an occlusive follicular disease. Future studies will be needed to clarify the prevalence and comorbidities of the ‘Cystic Sponge Anus’.