Anorectal hemangioma, a rare cause of lower gastrointestinal bleeding, treated with selective embolization: A case report

Abstract

BACKGROUND

Anorectal hemangioma is a rare and frequently misdiagnosed cause of lower gastrointestinal (GI) bleeding. Here, we present a minimally invasive therapy with selective embolization.

CASE SUMMARY

A 21-year-old male patient experienced painless rectal bleeding since childhood and was treated for ulcerative colitis. Diagnostic studies later revealed specific characteristics for vascular lesions-anorectal hemangiomas. The severity of rectal bleeding caused symptomatic anemia and possible surgical treatment was associated with a high risk of fecal incontinence. Here, we present selective embolization, a minimally invasive therapeutic approach that is proven as an alternative therapeutic method of choice. The patient significantly improved temporarily and had a small ischemic ulcer, which healed with a control colonoscopy and developed no stenosis.

CONCLUSION

Awareness of the clinical and radiological features of GI hemangiomas may help improve diagnostics and avoid inappropriate therapeutic procedures.

Key Words: Hemangioma; Vascular malformation; Gastrointestinal hemorrhage; Rectal bleeding; Phlebolith; Selective embolization; Case report

Core Tip: Anorectal hemangioma is a rare and frequently misdiagnosed cause of lower gastrointestinal bleeding. Surgical resection of the affected area is acknowledged as a treatment of choice; however, we present a minimally invasive therapeutic approach - selective embolization. This may be performed in a specific group of symptomatic patients for whom the risks and disadvantages (such as ostomy) of the surgical procedure outweigh the possible benefits.

INTRODUCTION

Anorectal hemangioma is a rare cause of lower gastrointestinal (GI) bleeding. GI hemangioma, first described in 1839[1-4], typically manifests as rectal bleeding and is commonly misdiagnosed despite many reported cases[1-3,5]. Here, we present a case of a 21-year-old male patient with painless rectal bleeding since childhood and misdiagnosed with ulcerative colitis. He was treated with minimally invasive selective embolization after a successful anorectal hemangioma diagnosis.

CASE PRESENTATION

Chief complaints

A 21-year-old male patient who experienced painless rectal bleeding since childhood was referred to our gastroenterological center.

History of present illness

He experienced intermittent rectal bleeding since childhood and was treated for ulcerative colitis.

History of past illness

He was treated with azathioprine and mesalazine for ulcerative proctitis since 13 years of age. During the years, he presented with intermittent rectal bleeding despite the medication. Rectal bleeding worsened, and he required blood transfusions due to symptomatic anemia. At 18 years of age, he switched to a gastroenterologist for adults and was referred to a specialized gastroenterological center for appropriate atypical endoscopic finding management.

Personal and family history

He experienced no other diseases and had no history of trauma or surgery. He reported no family history of inflammatory bowel diseases or other relevant diseases.

Physical examination

The patient presented with an anemic appearance, with no abnormalities during a digital rectal examination.

Laboratory examinations

Serology (antineutrophil cytoplasmic antibodies and anti-saccharomyces cerevisiae antibody) was negative and blood tests revealed no signs of inflammation.

Imaging examinations

Control colonoscopy revealed significantly dilatated veins starting from the anal verge and continuing to the rectosigmoid junction (Figure 1), histology demonstrated no inflammation, and gastroscopic findings were normal. Pelvic and abdominal computed tomography (CT) scan was performed which ruled out portal and pelvic vein thrombosis as a possible cause of rectal varices. Additionally, a CT scan revealed several phleboliths around the rectum (Figure 2), which appeared as an important diagnostic clue. Pelvic magnetic resonance imaging (MRI) was planned.

Figure 1 Endoscopic appearance. A: In rectosigmoid junction; B: In rectum mimicking rectal varices.

Figure 2  Abdominal computed tomography scan with phleboliths in pelvis.

FINAL DIAGNOSIS

MRI unveiled a rare vascular lesion-anorectal hemangioma (Figure 3).

Figure 3 Pelvic magnetic resonance imaging scan. Rectal wall thickening with serpiginous vascular structures in the mucosa and submucosa.

TREATMENT

A coloproctologist was consulted because the patient was still presenting with intermittent rectal bleeding and a repetitive need for blood transfusions due to symptomatic anemias. A possible surgical treatment was assumed to be associated with a high risk of fecal incontinence. We selected a minimally invasive procedure using modalities of interventional radiology, considering the risks and patient’s preferences.

Our patient underwent angiography of the inferior mesenteric artery (Figure 4A and B) as well as partial embolization of rectal branches using polyvinyl alcohol (PVA) microparticles (Figure 4C). Angiography revealed a slightly hypertrophied inferior branch mesenteric artery, where we embolized with 300 microns and then mainly 500-700 microns PVA particles. Embolization was incomplete due to a marked slowing of blood flow.

Figure 4 Angiography. A: Before embolization with polyvinyl alcohol microparticles; B: Before embolization with venous phase and characteristic “stippling” of the lesion; C: After the second embolization.

OUTCOME AND FOLLOW-UP

So far, the patient has had to undergo this treatment twice at a 9-month interval. He experienced mild rectal pain after the second embolization. Endoscopy revealed a significant vascular lesion regression as well as a small ischemic ulcer of the rectosigmoid junction, associated with the embolization procedure. The pain disappeared shortly and a follow-up colonoscopy revealed no ulcer (Figure 5). One year follow-up after these procedures indicated that rectal bleeding became less frequent and intensive, but parenteral iron therapy is still required despite verified endoscopic regression.

Figure 5  Endoscopic appearance after the second embolization.

DISCUSSION

Classification and clinical manifestation

Anorectal hemangioma was considered a benign vascular tumor; however, these colonic hemangiomas are categorized with venous malformations according to the latest classification (May 2018 by the International Society for the Study of Vascular Anomalies). Unlike hemangiomas, these malformations exhibit normal endothelial cell turnover[2]. The most common type is “cavernous hemangioma” representing 80% of cases, capillary, or mixed occupying the rest[2,3,5]. GI hemangiomas generally occur more predominantly in the small intestine than in the large intestine and most colonic hemangiomas are located in the rectum and sigmoid colons[5,6]. The term hemangioma has been used because of its clinical familiarity and its possible existence in the GI tract. However, far more frequent vascular malformations, such as “cavernous hemangioma” are found[5].

Clinical presentation of anorectal vascular malformation is predominant with enterorrhagia of varying severity in children and young adults and causes secondary sideropenic anemia[3,7]. Approximately 10% of patients with colonic malformation remain asymptomatic[1,2]. Several syndromes, such as Rendu-Osler-Weber, blue rubber bleb nevus, Maffuci, and Klippel-Trenaunay-Weber, with characteristic organ involvement, were observed although GI vascular malformations may be solitary or multiple and may exist as separate entities[2,5,6,8].

Diagnosis

Colonoscopy is considered a gold diagnostic standard as it helps evaluate the morphology and size of the lesion. Blue nodular lesions are typical results in diffuse cavernous vascular malformation and represent submucosal veins, which are dilatated and engorged[4,9]. In our patient, these lesions were present but were initially misdiagnosed as inflammatory changes by a pediatric gastroenterologist. Generally, rectal cavernous vascular malformation should not be biopsied due to a high risk of bleeding[1-3,5,7,9].

Both MRI and CT scans are selected for imaging methods. They both may reveal an irregular bowel wall thickening as well as the extent of the lesion and possible adjacent organ involvement. CT scan revealed a crucial diagnostic clue, phleboliths, which are most prevalently found in the pelvis[1,2]. Phleboliths are rounded hyaline-organized thrombi that are visible on imagining when calcified[10]. Phleboliths were also present in our patient. However, MRI is the preferred diagnostic method, especially when considering surgery. It helps evaluate the extent of anal canal invasion as well as sphincter involvement[4,9]. MRI reveals hypointensity on T1-weighted and hyperintensity on T2-weighted imaging[2,4,8].

Therapy

An affected area surgical resection is generally a treatment of choice. The sphincter-saving procedure is preferred if technically feasible with anterior rectal resection and colo-anal anastomosis. Additionally, extracolonic organs can be affected; therefore, a thorough abdominal cavity exploration must be performed[9]. Endoscopic resection should be preferred to surgery in cases of pedunculated lesions. However, bleeding and perforation are a high risk; thus, having a careful endoscopic approach and adequate bleeding prophylaxis is important[11].

A minimally invasive selective embolization should be considered in a specific group of symptomatic patients for whom the risks of the surgery and disadvantages (such as ostomy) of the surgical procedure outweigh the possible benefits. In our case, PVA microparticles were used for partial embolization only, considering the risk of ischemia and the possibility of causing stenosis. Additionally, we found only one ischemic ulcer in the rectosigmoid junction that healed without subsequent stenosis. In general, these PVA microparticles induce mechanical occlusion, cause thrombus, and induce inflammatory response characterized by vessel wall angionecrosis. PVA is considered a permanent embolic agent as it is not biodegradable[12]. However, vessel recanalization and bleeding recurrence after this procedure are not exceptions[9,12]. Selective embolization of the rectal branches of the inferior mesenteric artery is performed for treating symptomatic hemorrhoids (Vidal). In patients with less severe symptoms, an even more conservative approach, ferrum substitution, may be considered, which is eventually combined with blood transfusions if required.

CONCLUSION

In conclusion, anorectal vascular malformation, with only a small number of case reports, is a rare cause of rectal bleeding, and misdiagnosis is frequent because of a lack of awareness. More uncommon causes must be considered, such as GI hemangiomas and vascular malformations, in cases of atypical clinical, imaging, or endoscopic findings in patients with rectal bleeding.

With this case report, we aimed to present a treatment using a minimally invasive method, selective embolization. Our patient still experiences rectal bleeding episodes and requires ferrum substitution, but we consider this treatment successful as it had a major impact on improving the quality of his life, and the patient no longer required blood transfusions during our one-year follow-up.