Pyogenic Granuloma of the Colon in Children

Abstract

INTRODUCTION Pyogenic granuloma, a polypoid form of capillary hemangioma, commonly occurs on the skin and mucosal surfaces but, except for the oral cavity, only rarely occurs in the gastrointestinal tract (1). It was initially reported by French surgeons Poncet and Dor (2) in 1897 (3). In a large series of 289 patients (4), the commonest site was the gingivae (32.7%), followed by fingers (22.5%), lips (20.4%), face (14.3%) and tongue (10%). We report 2 children with colonic pyogenic granulomas who presented with rectal bleeding. CASE REPORTS Patient 1 was a previously healthy 5-year-old girl who presented with a 2-month history of painless rectal bleeding. She had no fever, abdominal pain or weight loss. Her physical examination result was normal. Colonoscopy revealed a 4-mm polypoid lesion in the rectum (Fig. 1) that was thought to be a juvenile polyp. It was removed by snare and cautery without complications. Histological evaluation revealed a lobular capillary hemangioma/pyogenic granuloma that consisted entirely of small and dilated capillaries and a loose connective tissue stroma (Fig. 2).FIG. 1: Polypoid lesion with stalk in the rectum.FIG. 2: Lobular capillary granuloma with small and dilated capillaries and a loose connective tissue stroma.Patient 2 was an 18-month-old girl with intermittent fever and rectal bleeding. At age of 7 months, she had received an orthotopic liver transplantation for biliary atresia. An abdominal computed tomography scan revealed bowel wall thickening in the left midabdomen with localized fatty proliferation in the mesentery. Colonoscopy revealed an area of circumferential black necrosis at the splenic flexure (Fig. 3). Histological examination of several pinch biopsies revealed fibrous scar tissue with areas of proliferating capillaries surrounded by inflammatory cells (Fig. 4). Two weeks later, colonoscopy was repeated. Examination of the same area showed scarred mucosa with circumferential narrowing but no necrotic tissue. Biopsy revealed a small focus of granulation. She had received antibiotic and antifungal therapy between the 2 endoscopies. Cultures of stool, blood and urine were negative.FIG. 3: Black necrotic circumferential lesion at the splenic flexure.FIG. 4: Several fragments of fibrous scar tissue with areas of proliferating capillaries surrounded by inflammatory cells.DISCUSSION Pyogenic granuloma is a benign inflammatory soft tissue growth arising from the connective tissue of the skin or mucous membrane. By histology, it is a capillary hemangioma resembling granulation tissue that typically appears as a single nodule on the oral mucosa, face or upper extremities (5). It is considered as a polypoid form of capillary hemangioma. It may present as an ulcerated surface which can be necrotic and covered by a white slough. It usually appears as a smooth, lobulated, pedunculated or sessile mass. It is highly vascular and may bleed spontaneously or upon manipulation. If hemorrhage occurs inside the lesion, it may take on a melanotic brown color. During its early stages, it is soft or spongy in consistency. As it ages, the capillaries can become obliterated, leading to a more fibrous appearance. The definitive diagnosis is made only by histopathologic examination, which shows granulation tissue, with anastomosing endothelial-lined vascular spaces with fibroblast proliferation and endothelial cell budding. It was initially described as human botryomycosis by Poncet and Dor (2), and in 1904, Hartzell (6) described similar cases and coined the term "pyogenic granuloma." He believed that the lesion was a nonspecific and reactive type of granulation tissue. Recently, Mills et al. (7) advocated designating this tumor as a "lobular capillary hemangioma." The lesions are usually painless and bleed easily (8). Solitary pyogenic granulomas are common and represent 0.5% of all skin nodules in children. They usually present as a rapidly growing, firm, bright red papule that is prone to bleeding or ulceration. The exact etiology is unknown. Pyogenic granulomas have usually been viewed as hyperplastic granulation tissue that appear as a reaction to local irritation. Postulated predisposing factors include trauma, hormonal influences such as pregnancy, bacterial and viral infections, microscopic arteriovenous anastomoses and angiogenic growth factors. Although pyogenic granuloma is common in the skin and oral cavity, it is rare in the gastrointestinal tract. To date, 12 cases of gastrointestinal pyogenic granuloma have been described in adults: 4 in the esophagus, 2 in the stomach, 5 in the small intestines and 1 in the colon. Morphologically, 9 have been pedunculated or semipedunculated, and 3 have been sessile (1,3,9-14). Serban et al. (15) reported their experience of colonic pyogenic granuloma in Romanian children. They reported 11 children with colorectal polyps. Of these, 2 had a typical appearance of pyogenic granuloma, and one had a polyp related to mucosal prolapse syndrome in which a small area of pyogenic granuloma was found. They noted no pathological flora was in the stool. The polyps did not recur after removal. Recurrent pyogenic granuloma has been reported in an adult kidney transplant patient. It is important to differentiate pyogenic granuloma from Kaposi sarcoma or bacillary angiomatosis as both frequently occur in immunosuppressed patients (16). In conclusion, pyogenic granuloma can occur in the gastrointestinal tract of children and usually presents with rectal bleeding. It has polypoid or sessile black necrotic appearance. The diagnosis is made by histopathology. Endoscopic snare polypectomy or surgical resection is appropriate for definitive diagnosis and treatment.