Rectal Adenocarcinoma With Pagetoid Spread: A Novel Entity.

Perianal Paget's disease (PPD) is a rare skin adenocarcinoma that arises in the apocrine glands of the perianal region. It is often misdiagnosed as eczema, leukoplakia, squamous cell carcinoma, Bowen's disease, lichen planus, or condylomata acuminata. We report a case of a 63-year-old male who presented to the emergency room (ER) for evaluation of an anal mass that had persisted over 6 months. The patient was found to have a rectal adenocarcinoma with pagetoid spread and underwent neoadjuvant chemoradiation with symptom improvement. However, the patient declined further chemotherapy and the planned abdominal perineal resection with reconstruction, as it would require a permanent colostomy.