This is a 66-year-old man who was evaluated for anemia by upper endoscopy and colonoscopy. The colonoscopy was unremarkable but, based on the results of the endoscopic biopsies, the upper endoscopy showed what appeared to be a benign villous adenoma in the third portion of the duodenum. The patient was referred for EUS evaluation, and this study showed a superficial tumor that did not involve the muscularis propria. However, there was one 1.7-cm-diameter lymph-node-like structure immediately adjacent to the involved area. EUS-guided fine-needle aspiration (FNA) of the lymph node revealed adenocarcinoma.

In this case the presence of metastatic lymphadenopathy proven by EUS allowed the diagnosis of adenocarcinoma and indicated the need for surgery. An article from UCLA Medical Center summarizing 40 years of experience with this rare tumor reported that prognosis of duodenal cancers was related more to tumor size, local invasion, and histologic grade than tumor spread to local lymph nodes and that the disease can be potentially curable by surgery even with local lymph node involvement [1]. However, more recent articles have found that metastatic lymph node involvement decreases the rate of survival. A study from the Memorial Sloan Kettering Cancer Center showed that survival at 5 years was 83 % in patients without nodal invasion and was 56 % in those with positive nodes [2]. A recent publication from Johns Hopkins reported that 5-year survival was 68 % in patients without lymphadenopathy versus 58 % in those with 1–3 positive nodes and 17 % in patients with ≥4 positive nodes [3]. In summary, lymph node involvement is again considered a significant prognostic factor, and EUS/FNA has the ability to provide this information.

Duodenal diverticula can be mistaken for cystic pancreatic abnormalities on cross-sectional imaging, especially when they are not filled with air or contrast but fluid [4]. These are two patients in whom periampullary duodenal diverticula and the absence of pancreatic cystic lesions were nicely demonstrated during EUS.

Duodenal diverticula are common in the periampullary area. The presence of these diverticula can limit the evaluation of the distal common bile duct (CBD) or periampullary region on standard imaging studies. Diverticula can contain debris, and they usually fill with air during standard endoscopy. Careful endoscopic visualization of this area is important to avoid false EUS interpretations, particularly if scanning from the duodenal bulb. In these cases filling the diverticulum with water provides appropriate ultrasound wave transmission and allows for a reliable interpretation of adjacent structures.

A 65-year-old woman presented with abdominal pain, weight loss, and fever. A computed tomography (CT) scan of the abdomen showed a retroperitoneal abscess. A duodenal perforation was suspected. The initial upper endoscopy was reportedly unremarkable. The patient was referred for EUS evaluation. Surface endoscopy during EUS showed a duodenal microperforation. EUS showed an echogenic shadowing structure (not air) directly behind the perforation site. Since nothing was seen on the CT scan in this location, a toothpick or a fish bone were the prime suspects. The patient was treated with percutaneous drainage and long-term antibiotics. Eight weeks after the initial presentation she developed portal vein thrombosis, probably related to the presence of the abscess.

Metallic objects (except aluminum), most animal bones, and all glass foreign bodies are opaque on radiographs. Most plastic and wooden foreign bodies and most fish bones are not opaque on radiographs. These can be missed occasionally by CT scan [6], as shown in this case. Ultrasound techniques are helpful in the detection of wooden foreign bodies as small as 2.5 mm long, as shown in multiple reports [7–9].

A systematic review of injuries related to toothpick ingestion reported between 1966 and 2000 [10] found that most patients (70 %) present with abdominal pain, and most commonly reported complications include perforation, bleeding, peritonitis, abscess, or obstruction. However, only a minority (12 %) of patients remembered swallowing a toothpick. The most common site of injury is the duodenum (25 %), although this can occur throughout the entire gastrointestinal tract, and the toothpicks can migrate to the pleura, pericardium, peritoneum, ureter, or bladder. Major vessel involvement can also occur. Therefore, it is important to define the exact location of the entire toothpick before attempting endoscopic removal, which is contraindicated in patients with peritonitis or vessel penetration [11].

This is a 42-year-old man with a drug and alcohol problem who was admitted to the hospital with intractable abdominal pain and because a CT scan had shown a paraduodenal mass. An EUS was requested for further evaluation of multiple abnormalities seen on CT. The EUS showed that there was actually a smaller cyst within the duodenal wall and another larger one, characteristic of a pseudocyst, adjacent to it. The small cyst, if it had been isolated, would have probably been called a duplication cyst. However, the clinical context and the fact that it had resolved 6 months later make it much more likely that this is a duodenal wall intramural pseudocyst.

Pseudocysts that migrate into the wall of the duodenum or elsewhere in the gastrointestinal tract, including the stomach and colon, have been reported [12], but awareness of this phenomenon is limited in the medical community. Duodenal pseudocysts are found between the muscularis propria and the mucosa or between serosa and muscularis propria. The surface of the posterior wall of the duodenum is in direct contact with the head of the pancreas, without a clear barrier to the disruptive effect of pancreatitis and pseudocysts. Complications of these lesions include perforation or duodenal obstruction. EUS allows for the detection of these cystic-appearing lesions, which can be confirmed by aspiration of fluid rich in amylase [13].