We discuss the case of a young adolescent boy with ulcerative colitis who developed pneumomediastinum and subcutaneous emphysema in the neck and surrounding cervical soft tissues secondary to a probable retroperitoneal perforation of the colon. To our knowledge, this is the first reported case of this complication in the pediatric literature. Our experience provides insight into this unusual complication, how it may present, and its clinical significance in young patients with ulcerative colitis. The literature on this complication is also discussed.