The authors present the case of a 40-year-old white man with an obstructing laryngeal mass. Despite considerable tumor size, results of repeated biopsies revealed widespread carcinoma in situ with chronic inflammation within the subcutaneous tissues, and only after extensive endoscopic "debulking" of the mass was a small focus of invasive carcinoma identified. Just as surprising was the patient's unusual degree of immune competence as estimated to be at least in the upper normal range and definitely much higher than that observed in the other patients with head and neck cancer routinely examined in our department. The immune responsiveness of the patient was evaluated by total lymphocyte count, in vivo skin testing, in vitro blastogenesis, interleukin-2 and interferon-gamma production. The authors postulate that these observations may constitute a rare demonstration of the ability of the immune surveillance system to contain malignancy under physiologic conditions.