EP1043 - Case Report of Anal Squamous Cell Carcinoma with Associated Fistulous Tract and Condyloma

Purpose/Background: Condyloma acuminata, caused by human papilloma virus (HPV) infection, presents as fleshy plaques or papules around the perianal skin, anal canal, and genitals. These lesions can harbor high-grade squamous intraepithelial lesions (HSIL) or squamous cell carcinoma (SCC), necessitating excision or fulguration followed by surveillance. HPV is also the primary etiology of anal SCC, driving changes in management of condyloma. Anal fistulas, typically arising from obstructed anal glands and subsequent infection, rarely present as a manifestation of anal SCC. We present a rare case of perianal condyloma harboring SCC along a fistulous tract.

Methods/Interventions: A 43-year-old male presented with a painful perianal mass, rectal bleeding and intermittent purulent discharge. He denied constitutional symptoms, fecal incontinence, or anal intercourse. Medical history included hypertension, diabetes, obesity. Social history included tobacco use and occasional alcohol and marijuana use. Family history was negative for colorectal cancer or IBD. He was HIV negative. On exam, he had a wart-like lesion in the right perianal region, suspicious for condyloma with possible fistula-in-ano. He was taken to the OR for exam under anesthesia and excision.

Intraoperatively, a 2.5cm verrucous mass at the 9 o’clock position, 3 cm from the anal verge, was elliptically excised using a no-touch technique.Purulence was noted at be base but no definitive no fistulous tract could be identified or probed in the base or in the anal canal. The wound bed was closed.

Results/Outcomes: Final pathology demonstrated invasive keratinizing SCC in a background of high-grade squamous dysplasia (AIN 3) and a squamous-lined fistula tract with dysplasia and separate foci of SCC with positive deep margin ( < 0.1cm). The tumor was p16-positive with TNM stage of at least cT2cN0cM0.

Postoperative imaging showed no evidence of metastasis. Pelvic MRI identified a right intersphincteric fistula, with enhancement consistent with inflammation, with no involved mass, abscess, or lymphadenopathy.

He was discussed in multidisciplinary tumor board and was treated with chemoradiation therapy, with planned re-excision for residual disease.

Conclusion/Discussion: Anal SCC presenting as anal condyloma with fistula is rare. While malignant transformation of chronic anal fistulas, typically as adenocarcinoma, has been documented, SCC in this setting is uncommon and is more frequently associated with Crohn’s disease, HIV, or prior radiation. The presence of anal condyloma with anal fistula may be an additional risk factor. This case highlights the potential for malignant transformation in the setting of perianal condyloma with associated fistula. The presence of an anal condyloma with suspicion for fistula, especially in the presence of additional risk factors, should also elicit concern for underlying malignancy.