Lymphangioma of the anal canal: first description of the endoscopic features

Abstract

A 42-year-old woman was referred to our hospital for the work-up of iron deficiency anemia. Esophagogastroduodenoscopy (EGD) did not reveal a bleeding source. The appearances on total colonoscopy were normal except for a 20-mm submucosal tumor in the left lateral anal canal (• " Fig. 1). The tumor could be compressed with the endoscope, indicating that it was soft. It was also translucent and lustrous. The tumor and the mucosa surrounding its base were lined with stratified squamous epithelium. Narrow-band imaging (NBI) revealed scattered bullous-like transparent areas on the tumor surface (• " Fig. 2 a). Magnifying endoscopy with narrow-band imaging (ME-NBI) of these areas demonstrated elongated, dark-brown, looping capillary vessels, without dilatation or caliber change, in the superficial layers (• " Fig. 2 b). In addition, small blood vessels were observed in the deeper subepithelial layers (• " Fig. 2 c). The tumor was totally removed using endoscopic submucosal dissection (ESD) and was diagnosed histologically as a lymphangioma (• " Fig. 3). Lymphangiomas of the anal canal are extremely rare. To the best of our knowledge, there are only two previous cases reported, and neither of these included detailed endoscopic findings [1, 2]. Here, we present the notable epithelial and microvascular findings on ME-NBI of an anal lymphangioma for the first time. By comparing the endoscopic and histological findings, we presume that the continuous stretching by distended lymphatic channels resulted in the thinning of the overlying squamous epithelium. This probably caused mucosal transparency and capillary elongation, resulting in the visualization of deeper stromal microvessels. In a case report of esophageal lymphangioma [3], very similar ME-NBI findings were described as being characteristic features. Because the anal canal and esophagus are both covered with stratified squamous epithelium, the ME-NBI diagnostic criteria used for esophageal lymphangioma may also be applicable to anal lymphangioma, as is the case with squamous cell carcinoma [4, 5]. We consider that these unique endoscopic findings might be characteristic of lymphangioma of the anal canal and could be useful in making this diagnosis.

A Case of Lymphangioma of the Anal Canal

“…Also, we suggest total excision and biopsy of these tumors as the treatment of choice, as well as any excised lesion of the area, due to the possibility of missing a potential histologic diagnosis. The excision can be done either surgically as in this case or endoscopically as described in other reports, by snare polypectomy [4] or endoscopic submucosal dissection [3]. We await new information about this neoplasm in the years to come that will help the medical community better understand this interesting entity.…”

“…The clinical presentation of lymphangiomas can vary, from asymptomatic to iron deficiency anemia or rectal bleeding [1, 3, 4]. Our patient had vague symptoms of anal discomfort and mild rectal bleeding.…”

“…Cases of lymphangiomas occurring on the lower gastrointestinal tract have been rising in the past years, probably due to the extensive use of specialized diagnostic examinations. So far, lymphangiomas of the anal canal have been extremely rare, since only 3 other cases [1, 3, 4] have been reported to our knowledge. Consequently, little information is available to establish an accepted course of action, in order to properly diagnose and treat potential new cases.…”

“…The endoscopic findings using magnifying endoscopy with narrow-band imaging techniques could be useful in making the diagnosis of a lymphangioma, as suggested by a report [3]. Mucosal transparency and capillary elongation are identified as unique endoscopic findings that could be a characteristic of a lymphangioma.…”