So Now My Patient Has Squamous Cell Cancer: Diagnosis, Staging, and Treatment of Squamous Cell Carcinoma of the Anal Canal and Anal Margin

Abstract

Squamous cell carcinomas of the anal canal and the anal margin are rare malignancies that are increasing in incidence. Patients with these tumors often experience delayed treatment due to delay in diagnosis or misdiagnosis of the condition. Distinguishing between anal canal and anal margin tumors has implications for staging and treatment. Chemoradiation therapy is the mainstay of treatment for anal canal squamous cell, with abdominoperineal resection reserved for salvage treatment in cases of persistent or recurrent disease. Early anal margin squamous cell carcinoma can be treated with wide local excision, but more advanced tumors require a combination of chemoradiation therapy and surgical excision.

Keywords: abdominoperineal resection; anal squamous cell carcinoma; chemoradiation; wide local excision.

Fig. 1

Anal canal squamous cell carcinoma extending to the anal margin. As there is an anal canal component, this should be treated as an anal canal carcinoma. The patient's diagnosis was delayed by several months, as she was initially thought to have hemorrhoids on evaluation by her primary care physician and gastroenterologist.

Fig. 2

Squamous cell carcinoma involving the anal canal, anal margin, perineum, scrotum, and perianal skin. Delayed diagnosis and management may occur due to patient factors such as embarrassment or denial. (Photo courtesy of Mark Welton, MD.)

Fig. 3

Very large condyloma with a focus of invasive squamous cell carcinoma on final pathology. As this lesion is completely visible upon effacement of the buttocks, it is considered an anal margin lesion.

Fig. 4

Salvage abdominoperineal resection for persistent or recurrent anal canal squamous cell carcinoma after primary chemoradiation therapy often requires perineal reconstruction, preferably with a vertical rectus abdominis myocutaneous flap, due to the resulting large perineal defect and history of high-dose irradiation. (Photo courtesy of Gordon Lee, MD.)

Fig. 5

Female patients with persistent or recurrent anal canal squamous cell carcinoma often require en bloc posterior vaginectomy to obtain clear margins. Using the skin paddle of the vertical rectus abdominis myocutaneous flap to reconstruct the posterior vaginal wall and the rest of the perineal defect can offer excellent outcomes. (Photo courtesy of Gordon Lee, MD.)

Fig. 6

Perineal defect after salvage abdominoperineal resection for persistent anal canal squamous cell carcinoma. (Photo courtesy of Arash Momeni, MD.)

Fig. 7

Reconstruction of the perineal defect with a vertical rectus abdominis myocutaneous flap. (Photo courtesy of Arash Momeni, MD.)