A 71-years-old male patient, with no relevant past medical history or family history, asymptomatic, came to our unit for a screening colonoscopy. The endoscopic examination revealed a sessile polyp-like lesion, with a spherical shape, smooth surface, hard consistency (cushion sign negative), about 10-mm-sized, located in the sigmoid colon, which was compatible with subepithelial lesion. It was decided for endoscopic resection (snare polipectomy). The polyp was subsequently evaluated by an experimental ultrasound technique performed ex-vivo, with linear probe of 10 MHz, in order to review its sonographic features, to confirm the complete resection and to provide immediate support and guidance in the management of the patient. The imaging evaluation revealed a discretely heterogeneous, solid, ovoid (7×5.2mm), hypoechoic, subepithelial lesion, surrounded by a 3mm-thick hyperechoic rim, corresponding to an interface between the surrounding water and the various layers of the intestinal wall. Since it was not possible to differentiate the several layers by ultrasound, we could not identify the precise layer from which the lesion emerged, but, considering its location, its likely origin was the muscularis propria layer. These findings excluded the possibility of lipoma and confirmed its complete excision (Figure 1). Findings from pathology confirmed that it was a leiomyoma (Figure 2).
Figure 1. Colonoscopy and ultrasound evaluation of subepithelial lesion after ressection.
Figure 2. Histological examination: colonic leiomyoma (A: H&E 40x; B: H&E 400x; C: Actin 200x).
Colonic leiomyoma is a rare, benign and usually asymptomatic subepithelial lesion which originates from the smooth muscle in the colon (muscularis mucosa or muscularis propria), representing less than 5% of all GI leiomyomas. However, it can sometimes be associated with abdominal pain, bleeding, obstruction or perforation, mainly when it has larger dimensions. Its endoscopic or surgical excision is often relevant due to the need of a differential diagnosis with other potentially malignant diseases. In this specific case, we merely tried to recognise and correlate post-resection sonographic
features of the lesion, with the traditional endoscopic US approach and the nature of the lesion, in an experimental setting.
Antonieta Santos1, Cátia Leitão1, Bruno Pereira1, Ana Caldeira1, Eduardo Pereira1
Department of Gastroenterology, Hospital Amato Lusitano , Castelo Branco, Portugal.