Submucosal tumors

The diagnosis of carcinoid and submucosal tumors by endoscopy or barium contrast studies is not easy since these tumors are usually covered with a normal mucosal layer. To determine the main portion of the wall stratification in the gastrointestinal wall in which the tumors lie is the most important part of diagnostic imaging of submucosal tumors. For this purpose, endoscopic ultrasound (BUS), including the use of an EUS-guided fine-needle aspiration biopsy (FNA), is the best choice (Arantes et al. 2004 Vandernoot et... 

Fig. 19.2. a Endoscopic feature of rectal carcinoid. A small (5 mm in diameter) submucosal tumor is demonstrated, b Endosono-graphy with a miniature ultrasound probe (12 MHz). A small round-shaped tumor (C) is demonstrated beneath the first layer and no changes in submucosal layer are seen... 

The most frequently encountered condition mimicking submucosal tumors is extramural compression. Diagnosis is achieved by demonstrating the normal five-layer structure in the elevated portion and the cause of compression, such as the adjacent spleen (Fig. 19.11). 

Pneumatosis cystoides intestinalis is not actually a submucosal tumor, but the endoscopic features resemble those of a submucosal tumor. Endoscopic ultrasound shows an echogenic spot with a comet-tail artifact in the submucosal layer, which represents the air bubble (Fig. 19.12). 

Fig. 19.9. a Sonography of the jejunal GIST. An oval-shaped tumor with a deep ulcer is demonstrated. The tumor is well demarcated and the contour of the tumor is smooth, b Color Doppler ultrasound of the tumor shows the rich vascularity, c Contrast-enhanced ultrasound reveals the rich perfusion with a focal perfusion defect inside the tumor (asterisk), d Endoscopic feature of the tumor. A submucosal tumor with a deep ulcer at the center is demonstrated... 

Transabdominal ultrasonography can be a useful alternative modality to BUS in the assessment of carcinoid or submucosal tumors. 

Arantes V, Logrono R, Faruqi S et al (2004) Endoscopic sono-graphically guided fine-needle aspiration yield in submucosal tumors of the gastrointestinal tract. J Ultrasound Med... 

Polkowski M, Palucki J, Butruk E (2002) Transabdominal ultrasound for visualizing gastric submucosal tumors diagnosed by endosonography Can surveillance be simplified Endoscopy 34 979-983... 

Lipomas are the most common submucosal tumors of the colon and are visualized frequently. Large lipomas may bleed, and heterogeneity within a lipoma is thought to correlate with internal hemorrhage. Lipomas are smoothly marginated filling defects within the colon with internal fatty attenuation (Fig. 14.14). 

An orthotopic model of mCRC with a high rate of metastasis to the para-aortic lymph nodes has been developed utilizing implantation of tumor cells into the submucosal layer of the rectum (11, 12). In these models, primary tumor burden is evaluated by measuring tumor volume with a caliper, while lymph node metastasis is evaluated histologically. 

We have developed a firefly luciferase-expressing HT-29 colorectal cancer cell line, HT-29LP, to realize the benefits of BLI with an orthotopic colorectal cancer model. Primary tumors were established by implantation of HT-29LP cells into the submucosal layer of the rectum of mice, and tumor growth and lymph node metastasis were evaluated. A positive control treatment... 

Fig. 14.1. (A) Implantation of HT-29LP tumor cells into the posterior wall of the rectum. The anterior wall of the anorectal area is cut 7 mm in length between two hemostats to prevent colonic obstruction, resulting from tumor progression. Tumor cells are then injected submucosally using a 27 G needle. (B) At the end of the study period, the abdominal cavity is exposed through a midline incision and para-aortic lymph nodes (arrow), located around the abdominal aorta, are removed and imaged ex vivo.

Fig. 16.4. a Sonographic image of an early (submucosal invasion) gastric cancer. Narrowing of the submucosal layer is demonstrated. b Endoscopic sonography of an early gastric cancer (submucosal invasion). There is narrowing of the submucosal layer beneath the tumor... 

Cysts and lymphangiomas are located in the submucosal layer (Figs. 19.3, 19.4). They are well demarcated by a thin wall and are anechoic. Posterior echo enhancement as an artifact is a characteristic figure. They show good compressibility and change their shapes with external compression. Color Doppler does not reveal any vascular structure inside. Often septal structures are seen inside the tumor. 

An ectopic pancreas is characterized as a hypoechoic tumor located mainly in the submucosal layer with thickening of the adjacent proper muscle layer (Fig. 19.6). A tiny cystic area representing the ductal structure may be demonstrated. 

A hemangioma is demonstrated as a hyperechoic tumor in the submucosal layer. Calcification is occasionally seen inside the tumor (Fig. 19.7). Since the blood flow of the capillaries making up the tumor is extremely slow, it is difficult to detect blood flow signals using the conventional color Doppler method. 

Fig. 19.4. Lymphangioma at the duodenal bulb. A cystic tumor (t) with septa is seen in the submucosal layer...

Fig. 19.5. Sonographic feature of a gastric lipoma (gl). A hy-perechoic tumor located in the submucosal layer is demonstrated...

Fig. 19.7. Endosopic ultrasound of a gastric hemangioma (gh). The tumor lies in the submucosal layer and calcifications inside the tumor are seen (asterisks)...

Fig. 10.2.1a,b. Sonographic appearance of a submucosal fibroid, a A well circumscribed hypoechoic round mass with some internal heterogeneity is characteristic of a leiomyoma, b Doppler can be used to show the hypervascularity of this benign tumor... 

Color, flat mucosal or submucosal irregularities, and vascularity are not depicted. No differentiation between mucous impact and tumor... 

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