Biomedical subjects
Publications and source records attributed to J L Buck.
Carcinoids are tumors of the diffuse endocrine system. They occur most frequently in the gastrointestinal tract. Although they are considered malignant, their biologic behavior varies. The radiologic and pathologic appearances of gastric, duodenal, ileal, appendiceal, and rectal carcinoids are presented.
This study was designed to determine the prevalence of colorectal neoplasia in healthy, asymptomatic adults with an age-related risk for colorectal neoplasia. Ninety patients were studied with air contrast barium enema and colonoscopy. The study population included 61 males and 21 females, with an age range of 51-82 yr (65 +/- 2 yr). Adenomatous polyps were found in 27% of males and 14% of females or 24% of patients overall. Sixty-six percent of these neoplasms were above the rectosigmoid junction and the mean size of the polyps was 6.5 +/- 1.2 mm. In two patients, carcinoma was discovered. A linear association between age and the prevalence of colonic neoplasia was not demonstrated. This study demonstrates a relatively high prevalence of colonic neoplasia in patients with an age-related risk.
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.
This paper is an overview of the imaging characteristics of primary carcinoma of the gallbladder, based on the premise that more general knowledge of the imaging patterns of the primary tumor and its modes of spread might increase the likelihood of accurate preoperative diagnosis of this lesion. Primary tumor patterns discussed and illustrated are: (I) an intraluminal mass, (II) focal or diffuse thickening of the gallbladder wall, and (III) replacement of the gallbladder by a mass. Illustrated patterns of tumor spread include direct extension and lymphatic and hematogenous metastases.
Cystic mesothelioma (CM) of the peritoneum is a rare, benign neoplasm that occurs predominantly in women and tends to recur locally. It has received little attention (to our knowledge, a single case report) in the radiology literature. Five cases of CM are presented. Computed tomography (CT) was performed in three cases, ultrasound (US) in four cases, and magnetic resonance (MR) imaging in one case. Twenty-eight cases reported in the literature are reviewed for comparison. CM shows a clear predilection for the surfaces of the pelvic viscera but is seen in other areas of the peritoneum and retroperitoneum. The neoplasm was intraperitoneal in three cases and primarily retroperitoneal in the other two cases. In all CT and US studies performed, a single large, multilocular cystic mass was demonstrated. MR imaging, performed in one case, showed that the lesion had signal characteristics typical of a watery collection low in solute concentration. It is concluded that CM of the peritoneum has a nonspecific multilocular cystic appearance on images, which does not permit it to be differentiated from other cystic lesions.
The scintigraphic appearances of 12 surgically proven cases of choledochal cyst were retrospectively reviewed. In seven of 12 cases, radionuclide accumulated in the choledochal cyst (i.e., the dilated common bile duct) in less than 1 hr. In three additional cases, delayed accumulation (1-24 hr) within the cyst was seen. In two of the 12 cases, no ductal activity appeared and the diagnosis of choledochal cyst could not be made, although in one of these two cases delayed images were not obtained. Other frequent findings included delayed or nonvisualization of the gallbladder (11 of 12) and the appearance of prominent intrahepatic ducts (five of 12). We conclude that hepatobiliary scintigraphy is a noninvasive test useful in the diagnosis of choledochal cyst.
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.
Seventeen proved cases of intrahepatic cholangiocarcinoma (ICAC) were reviewed to establish a radiologic-pathologic correlation. The most common appearance of ICAC at computed tomography (CT) is that of a single, homogeneous low-attenuation mass. Multiple low-attenuation lesions were present in four cases. Calcification was depicted by CT in three cases. At angiography, ICAC has a variable appearance with avascular, hypovascular, and hypervascular patterns possible. Portal obstruction was seen in only one case. The most common appearance of ICAC at sonography is that of a homogeneously hyperechoic mass, either single or multiple. In only one case was ICAC hypoechoic. Plain abdominal radiography demonstrated calcification in three patients and evidence of Thorotrast (thorium dioxide) deposition in one. Upper gastrointestinal series demonstrated abnormal gastric folds in two cases, corresponding to gastric invasion by ICAC. There were no characteristic radiographic findings, but the following features may be helpful in differentiating ICAC from other primary intrahepatic tumors, particularly typical hepatocellular carcinoma: a homogeneously echogenic or high-attenuation appearance on images that reflects the uniform nature observed at pathologic examination, the presence of calcification, and the uncommon invasion of portal or hepatic veins. Conversely, the presence of satellite lesions may blur the the distinction between ICAC and metastatic liver disease.
To better understand how the internal composition of ovarian teratomas influences their sonographic features, we compared their sonographic and CT appearances in 23 cases. Sixteen lesions had a mixed echo texture, with hypoechoic as well as echogenic components; two were anechoic and five were entirely echogenic. Correlation with the CT images showed that the fat present in most teratomas had variable sonographic appearances. Pure sebum was anechoic or hypoechoic, but fat intermixed with hair strands was echogenic and often attenuated the sound beam because of the numerous tissue interfaces created within the mass. The hypoechoic component of the teratoma corresponded, on CT, to low-attenuation fat in 12 tumors and to fluid in five. Most teratomas contained a dermoid plug, a protuberance arising from the tumor wall and containing hair follicles and often fragments of bone or teeth. On sonography, all dermoid plugs were seen as an echogenic mass, often associated with distal acoustic shadowing and protruding into the hypoechoic portion of the teratoma. When the dermoid plug was large and occupied most of the tumor, the entire teratoma appeared echogenic, with no discernible anechoic component. We found that three factors greatly affected the sonographic appearance of ovarian teratomas: the size of the dermoid plug, the presence and location of calcified elements, and the histologic composition of the fatty component.
A case of mycosis fungoides with diffuse cutaneous uptake of Ga-67 citrate is presented, and the possible causes of this uptake are discussed.
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BACKGROUND: To determine if infarction and necrosis is the cause of the confusing soft tissue density on CT within intussuscepting lipomas of the colon. METHODS: The clinical records, radiologic examinations, and pathologic specimens of all 13 cases of colonic lipomas collected from 1988 to 1994 studied by CT and surgically resected were retrospectively reviewed. Ten of these cases were associated with intussusception; the CT attenuation of the lead point was graded according to its relative fat/soft tissue density. Pathologic specimens were graded independently by a GI pathologist and graded according to the degree of infarction/fat necrosis. RESULTS: The lipomas ranged from 4 to 7 cm in diameter (mean = 5 cm). Only one case with intussusception, and all three cases without, demonstrated pure fat attenuation on CT and demonstrated pure fat histologically. One case demonstrated soft tissue attenuation and corresponded with the most severely infarcted specimen histologically; two cases with similar but less severe infarction/fat necrosis corresponded with less than 25% fat attenuation. These latter three cases were originally misinterpreted as malignancies rather than lipomas. Six cases maintained greater than 50% fat density and intermediate amounts of infarction/fat necrosis. CONCLUSION: Lipomas may have an atypical appearance when intussuscepted due to varying degrees of infarction/fat necrosis.
Islet cell tumors are rare pancreatic or peripancreatic neoplasms that produce and secrete hormones to a variable degree. These tumors are best divided on clinical grounds into those that produce a recognizable, clinically evident endocrine syndrome (ie, functioning) and those that exhibit no clinical evidence of hormone production (ie, clinically silent). Clinically silent tumors produce symptoms due to mass effect because of their large size. They are often partially cystic or necrotic. Functioning islet cell tumors usually manifest earlier in the course of the disease because of the distinctive signs and symptoms of the associated endocrine syndrome. Clinically silent and functioning tumors cannot be histologically distinguished reliably even with the use of immunohistochemical stains. Insulinoma and gastrinoma, the two most common functioning lesions, are typically small homogeneous masses. Other functioning islet cell tumors include glucagonoma, somatostatinoma, vipoma, and adrenocorticotropic hormone-producing tumor. Larger tumors are associated with calcification, cystic degeneration and necrosis, and a more aggressive behavior (local and vascular invasion as well as distant metastases). There are many different techniques for detection and characterization of these lesions that are usually chosen according to the radiologist's experience and preference. Treatment and prognosis of these lesions depend on the hormone produced, their size, and their behavior.