Cap Polyposis: Further Experience and Review

Cap polyposis is characterized by the presence of inflammatory polyps with a “cap” of granulation tissue. It may represent one end of a spectrum of conditions caused by chronic straining. This experience represents the second largest reported series of cap polyposis.

The case notes of all patients with histologically proven cap polyposis were reviewed retrospectively and clinicopathologic features identified. A MEDLINE search was performed from 1985 to 2002 using cap polyps, polyposis, and inflammatory polyp as key words and further hand search was undertaken of key references.

Eleven cases (9 males; median age, 20 (range, 15–54 years) of cap polyposis were diagnosed between 1993 and 2002. The commonest presenting symptoms were rectal bleeding (82 percent) and mucous diarrhea (46 percent). Chronic straining at stool and constipation were noted in seven of these patients (64 percent). Digital rectal examinations revealed polypoidal masses in the rectum in four patients (36 percent). All patients underwent colonoscopy. The commonest site of involvement was in the lower rectum (82 percent). One patient had polyps in the sigmoid colon and one patient in the transverse colon. Of 11 patients, 2 defaulted follow-up after colonoscopy. Three patients with solitary polyps had complete resolution of symptoms after polypectomy and remained symptom-free at three-month follow-up. The remaining six patients had persistent symptoms and required surgical intervention. Four underwent anterior resection and were all symptom-free at median of 48 (range, 18–72) months after surgery. One patient had transanal excision of rectal polyps and had recurrence at three months after surgery. This patient refused further treatment and remains symptomatic to date. One patient presented with recurrence of polyps at the coloanal anastomosis soon after a pull-through procedure. Total colectomy and ileal pouch-anal anastomosis was performed and the patient was free of symptoms at four months after surgery.

Cap polyposis is eminently treatable with good long-term prognosis and function. Patients with solitary cap polyp respond well to endoscopic polypectomy. However, patients with multiple polyps and concurrent anorectal pathology require surgical resection.