Islet cell tumors of the pancreas: pathologic-imaging correlation among size, necrosis and cysts, calcification, malignant behavior, and functional status

OBJECTIVE

The purpose of our study was to correlate the imaging and pathologic features of islet cell tumors with regard to tumor size, necrosis and cysts, calcification, malignant behavior, and functional status.

MATERIALS AND METHODS

We retrospectively reviewed the clinical, pathologic, and imaging features of all 133 cases of pathologically proved islet cell tumors of the pancreas seen at the Armed Forces Institute of Pathology. Clinical data, including the patients' symptoms and serologic characteristics, were used to distinguish hyperfunctioning tumors (those causing symptoms related to elevated serum polypeptide levels) from nonhyperfunctioning tumors; hyperfunctioning tumors were divided further into insulin-producing and non-insulin-producing types. All patients had at least one cross-sectional imaging study, including CT (n = 118), sonography (n = 42), or MR imaging (n = 22). Clinical, pathologic, and imaging features were evaluated and correlated with tumor size, necrosis and cysts, calcification, local invasion, vascular invasion, metastases, and functional status.

RESULTS

Islet cell tumors with areas of necrosis or cystic change found pathologically and on imaging studies (56/133) were larger (8.4 cm in mean transverse diameter) than homogeneous solid lesions (2.9 cm in mean transverse diameter) and were predominantly non-insulin producing (48/56) and nonhyperfunctioning (36/56). Of the 43 insulinomas, 35 were small (2.2 cm in mean transverse diameter), solid, and homogeneous. Larger size also was associated with calcification and malignant behavior, including local invasion, vascular invasion, and distant metastases.

CONCLUSION

Our findings show that cystic and necrotic islet cell tumors are usually non-insulin-producing and nonhyperfunctioning neoplasms and larger than the typically solid and small insulinomas. Calcification, local invasion, vascular invasion, and metastatic disease are more commonly seen with larger neoplasms.

CT findings of regression in intraabdominal desmoplastic small-cell tumor

We report the computed tomographic (CT) findings in a patient with intraabdominal desmoplastic small-cell tumor before and after 10 weeks of chemotherapy. This tumor is a rare, frequently fatal neoplasm of the peritoneum, seen predominantly in young males. Initial CT demonstrated large intraperitoneal masses, hepatic metastases, retroperitoneal and right axillary lymphadenopathy, ascites, and pleural effusion. Follow-up CT showed marked decrease of the main tumor bulk and complete regression in the axillary nodes.

Colorectal carcinoma in young patients: CT detection of an atypical pattern of recurrence

Colonic adenocarcinoma is an uncommon but aggressive neoplasm in patients under the age of 40. The goals of this study were to evaluate the utility of computed tomography (CT) in preoperative staging and detection of postoperative recurrences in young patients with colon cancer and to evaluate the pattern of recurrent disease. We reviewed 51 cases of adenocarcinoma in patients aged 40 years and younger. CT preoperatively staged 21 (72%) of 29 patients correctly and had a 100% positive predictive value for metastatic disease. Recurrent disease occurred in 23 (76%) of 30 nonstage D patients with at least 2 years of disease-free follow-up. CT accurately detected 21 (91%) of 23 cases of recurrent disease. Local recurrences were detected in 20 (87%) of 23 patients. Isolated local disease was the most frequent pattern of recurrence, seen in 17 (74%) of 23 patients. Hepatic metastases were rare and occurred in nine (13%) of 51 patients. Young patients with colon cancer have an increased prevalence of isolated local recurrences and decreased rate of hepatic metastases than the older population. In order to detect early, and therefore resectable recurrent disease, CT examinations should be obtained early and often in the postoperative period.

Hodgkin's disease of the gastrointestinal tract

Hodgkin's disease (HD) is rarely considered in the differential diagnosis of gastrointestinal (GI) disorders. We report eight cases of GI HD. The patients, ages 16-64, all with stage IV disease of varied histologic subtypes and GI symptoms including pain, upper or lower GI bleeding and/or obstruction. There was diffuse gastric fold thickening in one case, a large submucosal mass along the proximal greater curvature in another case, and a large ulcerating mass along the lesser curvature in the third case. Two cases of jejunal disease manifested as either a short or long segment of luminal narrowing with prominent mucosal nodularity. Another case exhibited a short area of complete mucosal destruction, irregular cavitation and intraluminal filling defect. In one additional case there was diffuse jejunal nodularity. Colonic involvement (two cases) presented as a solitary polypoid mass in transverse colon in one patient and severe narrowing of the descending colon with adjacent mesenteric mass on CT in another. We conclude that although rare in Hodgkin's disease, GI involvement should be considered, particularly in patients with stage IV disease.

Prevalence and duration of postoperative pneumoperitoneum: sensitivity of CT vs left lateral decubitus radiography

OBJECTIVE

The purpose of this study was to evaluate the prevalence, location, and duration of pneumoperitoneum in postoperative patients and to compare the sensitivities of CT and left lateral decubitus radiography in the detection of postoperative pneumoperitoneum.

SUBJECTS AND METHODS

Twenty-seven CT scans and 27 abdominal radiographs with the patient in the left lateral decubitus position were obtained prospectively in 17 patients after uncomplicated abdominal surgery. Fifteen patients were examined 3 days after surgery and 12 were examined 6 days after surgery. The studies were evaluated in a blinded fashion for the presence, location, and volume of free air. The presence of air on the radiographs and the presence and quantity of air on the CT scans were correlated with each subject's surgical procedure, age, sex, and body habitus.

RESULTS

Pneumoperitoneum was seen on 13 (87%) of 15 CT scans and eight (53%) of 15 radiographs obtained 3 days after surgery and on six (50%) of 12 CT scans and one (8%) of 12 radiographs obtained 6 days after surgery. The calculated volume of free air seen on the CT scans ranged from 0.3 to 5.8 ml. Sixty-two percent of collections by volume were located in the midline/parahepatic space, 22% in the pelvis, and 16% in the mesentery. Radiographs showed pneumoperitoneum in only nine (47%) of 19 examinations in which the corresponding CT scans showed free air. Findings on radiographs were false-negative in seven (87%) of eight obese patients in whom pneumoperitoneum was detected on CT scans.

CONCLUSION

The prevalence of pneumoperitoneum in the postoperative period based on CT findings is greater than that previously reported. Small amounts of pneumoperitoneum frequently collect along the anterior abdominal wall in two preferential spaces, the pararectus and midrectus recesses. The results of this study show that CT is significantly more sensitive than plain radiography for detecting small amounts of free intraperitoneal air in postoperative patients. Radiography is particularly insensitive for imaging obese and heavy patients.

The radiologic evaluation of acute abdominal pain of intestinal origin. A clinical approach

The patient with acute abdominal pain presents the attending physician with a wide and varied gamut of diagnostic possibilities. Prompt and accurate diagnosis is essential for the proper care and management of these acutely ill patients. Diagnostic radiology is often an integral part of the emergent evaluation of these patients. This article focuses on some of the key plain-film findings in the patients suffering from acute abdominal pain of intestinal causes and reviews the radiologic evaluation of several major abdominal conditions such as acute appendicitis, diverticulitis, inflammatory bowel disease, bowel ischemia, and infarction.

Calcified intrahepatic portal vein thrombus: distinction from intrahepatic choledocholithiasis

In a case of calcified intrahepatic portal vein thrombus CT demonstrated a branching calcified intrahepatic mass with peripheral enhancement following dynamic bolus contrast medium administration. The distinction from intrahepatic choledocholithiasis was made with normal cholangiography. Calcified portal vein thrombus should be considered an unusual cause of branching calcified intrahepatic mass on CT.

Radiology of the esophagus

Plain films, esophagrams, and cross-sectional imaging studies have important roles in evaluating patients with suspected esophageal disease. The strengths and weaknesses of each technique are described in this article. The salient radiographic features of various inflammatory and neoplastic conditions of the esophagus are also described, with emphasis on the value of high-quality triphasic esophagography.

Polypoid and pseudopolypoid manifestations of inflammatory bowel disease

The polypoid manifestations of the idiopathic inflammatory bowel diseases (ulcerative colitis and Crohn disease) are often confusing. Inflammatory polyps project above the level of the surrounding mucosa. Pseudopolyposis (in ulcerative colitis) or a cobblestone appearance (in Crohn disease) results when extensive ulceration develops and only scattered islands of relatively normal mucosa remain; thus, the ulcerated areas may be falsely perceived as the baseline and the islands as polyps. Postinflammatory (filiform) polyps--fingerlike projections of submucosa covered by mucosa on all sides--reflect healing of undermined mucosal and submucosal remnants and ulcers and are almost always multiple. Patients with ulcerative colitis or Crohn disease are at increased risk for developing adenocarcinoma. Occasionally, dysplasia occurs as a polypoid lesion. Dysplasia of the colon (mucosal atypia) is a histologic marker highly associated with adenocarcinoma. Because differentiating adenocarcinoma and dysplasia from inflammatory or postinflammatory polyps is sometimes difficult or impossible, endoscopy and biopsy are usually recommended for definitive diagnosis of suspicious lesions.

US-guided percutaneous laser ablation of liver tissue in a chronic pig model

The authors evaluated the safety of ultrasound (US)-guided percutaneous ablation of liver tissue using a neodymium-yttrium-aluminum-garnet (Nd:YAG) laser fiber placed through a skinny needle. The US appearance of the lesion was correlated with the pathologic findings in 19 pigs killed at 1-7 weeks. A 20-gauge needle was percutaneously placed in the liver, and a fiber with a 0.5-cm cladding-stripped tip was inserted. The Nd:YAG laser was fired for 6 minutes at 1-4 W. The early sonographic appearance was recorded, and the US appearance before the pigs were killed was correlated with the gross and histopathologic findings. There were no cases of abdominal bleeding or infection. Mild transient changes in liver function were seen. An initial strong echogenic focus decreased slightly in echogenicity for 10 minutes and then stabilized. Over 1-7 weeks, the 1-cm-diameter lesion decreased in size and developed an echogenic rim that correlated with a peripheral zone of inflammatory repair around a small central cavity and zone of necrosis. US-guided laser ablation of liver tissue is safe in this pig model, and the US appearance corresponds to a process of repair and removal of necrotic liver tissue.

Animal model for fluoroscopically guided laser application in the biliary tree

The purpose of this project was to develop an animal model for a fluoroscopically guided application of the contact neodymium-yttrium aluminum garnet (Nd-YAG) laser in the bile duct and identify the factors affecting the extent of damage to the duct wall. This model permits cholangiographic visualization of the duct during laser application. Laser damage is limited by using contact probes and firing the laser while slowly pulling the probe proximally into the duct. Sixteen common bile duct laser burns were produced in 14 dogs. Power settings of 8-25 W were used. The tension of the contact probe along the duct wall, termed "wall tension," was varied through intraoperative manipulation in order to mimic a variety of ductal geometries that might be encountered in clinical use. The authors produced duct damage ranging from a superficial burn to perforation. Power and wall tension were the most important factors in determining the depth and circumference of damage, and the use of 15 W or less did not perforate the duct.

Cronkhite-Canada syndrome: radiologic features

We report 6 cases of Cronkhite-Canada syndrome, analyze the patterns of involvement, and review the literature on this entity. There were 4 women and 2 men, with an average age of 58 years. The stomach was diseased diffusely in 5 and focally (distally) in 1. Small bowel polyps were detected in 4 patients. Patterns of involvement were classified as (a) innumerable small polyps carpeting large areas, (b) scattered varying-size polyps, and (c) sparse involvement with few small polyps. There was concordance of patterns between the stomach and colon in 5 of the 6 patients.

Colorectal hemangioma: radiologic findings

The authors correlated radiographs with the clinical and histologic data of 12 patients with colorectal hemangioma. All patients presented with rectal bleeding, which was chronic in seven. Phleboliths were also visible in seven cases, which correlated with chronic bleeding in five. On barium studies, three masses were soft and three produced rigid narrowing. The atypical features of rigid luminal narrowing, which might mimic a carcinoma, and hypovascularity correlated with chronic bleeding or visible phleboliths, which suggest the correct diagnosis of colorectal hemangioma.

Tumors of the small intestine with little or no malignant predisposition: a review of the literature and report of 56 cases

Benign small bowel tumors are rare. If those with malignant potential are excluded, a small group of truly benign lesions remains. Fifty-six cases of these small bowel tumors were analyzed for clinical data, pathologic diagnosis, number, size, location, and radiologic appearance. Lesions included lipoma, myoepithelial hamartoma, Peutz-Jeghers hamartoma, neurogenic tumors (including gangliocytic paraganglioma), Brunner's gland abnormalities, and inflammatory fibroid polyp. Location, number, and radiographic morphology can be helpful in reaching a more specific diagnosis. Age of patient and size of tumor may be helpful in the differential diagnosis; however, sex of the patient and clinical symptoms are not.

Mesenteric and omental cysts: histologic classification with imaging correlation

Forty-one cases of mesenteric and omental cysts are reported. Histologically, several specific types could be distinguished: lymphangioma, 19 cases; nonpancreatic pseudocyst, 11 cases; enteric duplication cyst, six cases; mesothelial cyst, three cases; and enteric cyst, two cases. A lymphangioma is usually a multiloculated cyst located in the mesentery that shows no discernible wall on computed tomography (CT) and may have characteristics of fat on CT and magnetic resonance imaging. Abnormalities in the small bowel mucosa were frequently noted on barium studies. A nonpancreatic pseudocyst is usually a unilocular or multilocular cyst located in either the mesentery or the omentum, with abundant debris sonographically and an enhancing wall on CT. An enteric duplication cyst is a unilocular cyst with an enhancing wall on CT. Mesothelial and enteric cysts are anechoic, thin-walled cysts. Emphasis is placed on the importance of identifying lymphangioma, which is more difficult to manage than the other forms of mesenteric and omental cysts.

Hepatoblastoma: radiologic-pathologic correlation in 50 cases

Fifty cases of hepatoblastoma were reviewed. Virtually all patients were infants or young children with hepatomegaly or a mass. Calcification seen on 11 of 20 radiographs was often in a pattern of small chunks, and eight of these correlated with osteoid formation in histologically mixed hepatoblastomas. Angiography generally showed tumor vascularity, sometimes with a spoke-wheel pattern. Suggestion of tumor nodularity or lobulation on sonography or computed tomography (CT) correlated with the gross appearance. The tumor was usually echogenic and occasionally had small hypoechoic or anechoic areas representing necrosis or hemorrhage. On CT it was usually hypodense, with minimal if any enhancement. The calcification pattern and demonstration of tumor lobulation with septation may help differentiate hepatoblastoma from other liver neoplasms in infants and children under 5 years of age.

Nodular regenerative hyperplasia of the liver: clinical and radiologic observations

This report describes 21 cases of nodular regenerative hyperplasia (NRH) and its clinical and radiologic features. NRH of the liver is an established pathologic entity that should not be confused with focal nodular hyperplasia, hepatocellular adenoma, or the regenerative nodules associated with cirrhosis. Correct diagnosis will prevent an unnecessary hepatic lobectomy should NRH be mistaken for hepatocellular adenoma. Unlike focal nodular hyperplasia, NRH may bleed, may be associated with portal hypertension in one-half of cases, and is often associated with a systemic disease such as a myelo- or lymphoproliferative disorder. Correct diagnosis is important because the prognosis in patients with NRH and portal hypertension is better than that in patients with portal hypertension due to cirrhosis. Radiologically, multiple nodules, large masses, or an apparently normal liver (containing nodules less than 0.5 cm in diameter) were visible. The nodules may take up technetium sulfur colloid and have variable echogenicity on sonography. They are often hypodense on CT without significant enhancement. The nodules may fill from the periphery on angiography, are vascular, and sometimes contain small hypovascular areas due to hemorrhage. A large nodule may rupture and cause hemoperitoneum. These findings may resemble some features of focal nodular hyperplasia, hepatocellular adenoma, or metastases. NRH is probably underdiagnosed owing to a lack of recognition of the entity and limited sampling of liver tissue by needle biopsy. Scintigraphy, sonography, and CT of the liver should be performed in cases of idiopathic portal hypertension to detect NRH. In cases with compatible findings, multiple needle biopsies or a laparoscopically guided needle biopsy or wedge liver biopsy should be recommended for definitive diagnosis.

Natural history of the obstructed rabbit appendix: observations with radiography, sonography, and CT

Chronic (1-3 months' duration) appendiceal obstruction was induced in 11 rabbits to assess the pathologic consequences and to study the associated radiologic, sonographic, and CT findings. Three pathologic/radiologic groups resulted with approximately equal frequency. In group A, the abscess was characterized by inflammatory cells in the lumen and wall of the appendix without mucin production. Calcification was shown radiographically, and sonography showed an anechoic or complex pattern. Group B, the "mixed response," was characterized by an intact hyperplastic mucosa, mucin secretion, and inflammatory debris in the lumen. Occasional calcification was present radiographically, and sonography showed a complex or hypoechoic pattern. In group C, true mucoceles had an intact hyperplastic mucosa, a mucin-filled lumen, and minimal inflammation. These were anechoic on sonography except for mobile foci of inflammatory debris. Chronic obstruction of the appendix results in a spectrum of pathologic responses with varying degrees of either inflammation and mucosal destruction or mucosal hyperplasia and mucin secretion. An abscess results when infection overwhelms the host's inflammatory responses. If the bacteria are destroyed by these defenses, a mucocele forms. An intermediate situation occurs when there is a mixed response with chronic inflammatory changes and an intact mucosa. This finding supports the existence of chronic appendicitis in humans.

Hemangioma of the spleen: radiologic-pathologic correlation in ten cases

Ten cases of hemangioma of the spleen were reviewed. Plain abdominal radiographs and scintigrams are helpful in specifying the splenic location. Calcification, either central punctate or peripheral curvilinear, can be detected on radiographs or computed tomographic (CT) scans. The spectrum form solid to cystic change observed in the pathologic specimens is reflected in analogous patterns on CT scans and sonograms: predominantly solid mass; mass with cystic spaces. The angiographic findings are nonspecific. It is possible to suggest the diagnosis of hemangioma of the spleen when an asymptomatic patient presents with a discrete splenic mass, particularly if there is evidence of calcification and cystic change within the lesion.

Undifferentiated (embryonal) sarcoma of the liver: radiologic-pathologic correlation

Undifferentiated (embryonal) sarcoma (UES) is an uncommon malignant mesenchymal hepatic tumor that occurs in older children and young adults. Fourteen cases are correlated with radiologic and pathologic findings. Radiologic findings reflect the spectrum of solid to cystic appearances observed in the gross specimens. Sonography typically demonstrates a large mass that may be predominantly solid with many small anechoic spaces or may be cystic. Computed tomography reveals a hypodense mass with hyperdense septa of variable thickness and a dense peripheral rim corresponding to the fibrous pseudocapsule of the tumor. Angiographically, UES is usually hypovascular with tumoral vessels, although hypervascular and avascular patterns occur. Prognosis of UES is poor, with a median survival of less than 1 year. Radiologists should be familiar with this malignant tumor since it may present as a large cystic hepatic mass, suggestive of a benign lesion.

Nonparasitic splenic cysts: a report of 52 cases with radiologic-pathologic correlation

We reviewed 52 cases of splenic cysts on file at the Armed Forces Institute of Pathology. There were 24 true (epidermoid) and 28 false (posttraumatic) cysts. The history and clinical presentations, including pain, splenomegaly, or mass, were similar in both groups. Radiologic manifestations included splenomegaly and the occasional identification of a distinct mass by conventional radiography even in the absence of calcification. The lesions produced a photopenic defect on nuclear scintigraphy and were avascular on angiography. Sonography and CT demonstrated a cystic lesion with occasional septations, wall trabeculation, and low-level internal echoes. Three false cysts demonstrated solid and cystic components on sonography and CT, corresponding to organizing hematoma within the cyst. Splenomegaly or a splenic mass of a predominantly cystic nature with no clinical evidence of echinococcus suggests the diagnosis of splenic cyst. Reliable radiologic distinction between true or false splenic cyst does not seem possible. Complex mass may represent a "transition" between hematoma and false splenic cyst.