A rare cause of rectal bleeding

QUESTION

An 18-year-old male student was admitted to our hospital because of a 2-month history of intermittent bloody stools. Furthermore, he complained of left abdominal pain, tenesmus, and weight loss of 5 kg. He had undergone a hemorrhoidectomy 2 years ago. He denied any relevant medical history. Moreover, he denied having the habit of smoking or alcohol consumption. On physical examination, mild tenderness without rebound tenderness was observed in his left abdomen. Digital rectal examination showed mild prolapse of the anus. Laboratory test results were unremarkable, except an albumin level of 3.1 g/dL (normal 3.8–4.5 g/dL) and a hemoglobin level of 10.9 g/dL (normal 13–15 g/dL). Colonoscopy was performed; it revealed circular tumor-like lesions in the distal rectum (Figure 1). Because the patient refused to undergo surgical resection of the rectal lesions, we planned endoscopic resection. We resected the rectal tumor-like lesions using snare polypectomy and sent them for pathological examination (Figure 2).

Figure 1.

Colonoscopy showed circular tumor-like lesions in the distal rectum

Figure 2.

The tumor-like lesions were resected by endoscopic mucosal resection

What is your diagnosis of these rectal tumor-like lesions?

ANSWER

Inflammatory cloacogenic polyp mimicking rectal cancer Histopathological examination of the rectal tumor-like lesions showed elongated, irregular crypts; surface erosion with exudate coating; abundant neutrophil infiltration; and capillary proliferation in lamina propria (Figure 3, hematoxylin-eosin stain, magnification ×40). Furthermore, hyperplasia of the fibromuscular stroma and upward extension of smooth muscle in the lamina propria were identified (Figure 4, hematoxylin-eosin stain, magnification ×100). On the basis of histopathological characteristics, a diagnosis of inflammatory cloacogenic polyp was made.

Figure 3.

Histopathology of the rectal tumor-like lesions demonstrated elongated, irregular crypts, surface erosion with exudate coating, abundant neutrophils infiltration and proliferation of capillaries in lamina propria (hematoxylin-eosin stain, magnification × 40)

Figure 4.

Histopathology showed fibromuscular stroma with smooth muscle upward extension in the lamina propria (hematoxylin-eosin stain, magnification ×100)

Inflammatory cloacogenic polyp is a rare disease arising from the anal transitional zone and lower rectum. The etiology of inflammatory cloacogenic polyp is believed to be related to chronic mucosal prolapse (1). The clinical course of inflammatory cloacogenic polyp is usually benign, and its clinical manifestations include rectal bleeding, tenesmus, and abdominal pain. Endoscopically, inflammatory cloacogenic polyp may present as polypoid growths at the anorectal junction and resembles an anorectal malignancy (2). These lesions are best visualized using a retroflexed maneuver in the rectum on colonoscopy. The diagnosis of inflammatory cloacogenic polyp depends on histopathological findings. Surgical resection is the mainstay therapy for inflammatory cloacogenic polyp (3). However, endoscopic polypectomy or endoscopic mucosal resection is another alternative. Moreover, a high-fiber diet and avoidance of prolonged straining are important for patients with this condition to reduce mucosal prolapse.