Von Meyenburg complexes of the liver: imaging findings.

PURPOSE: Our purpose was to present imaging findings of six cases proven or supposed to be von Meyenburg complexes (VMCs) with a basis of reviewing the pathologic literature and to describe imaging points for the diagnosis of typical VMC along with its differential diagnosis. METHOD: Six cases were diagnosed as VMC of the liver with imaging modalities (one had histopathologic proof). Both ultrasound (US) and CT were available for all cases, and MRI was used for three cases. Follow-up with US, CT and/or MRI was performed in five cases. RESULTS: US detected varying abnormalities of the livers in four cases. CT and MRI revealed multiple or numerous intrahepatic tiny (usually < 5 mm) cystoid lesions in all of the cases. The lesions were scattered throughout the livers, and some of them were located more frequently adjacent to the medium-sized portal veins than to the hepatic veins of similar size on CT. Moreover, some lesions were apparently located in the subcapsular areas (up to the hepatic capsules). They were usually irregular in shape and showed no enhancement but increased in number by approximately 80-150% after administration of intravenous contrast medium. The T2-weighted MR images and MR cholangiopancreatography showed the lesions to be much more apparent and to be more numerous than T1-weighted images did. Follow-up of five cases with imaging modalities did not show remarkable change of the lesions. CONCLUSION: Despite our limited experience, VMC lesions seem to show some CT and MR features different from those of other multiple small hepatic lesions. They presented as multiple or numerous intrahepatic tiny cystoid lesions usually with irregular contour, scattered throughout the liver up to the subcapsular areas, and were detected in far greater number by enhanced CT or T2-weighted MR images than by unenhanced CT or T1-weighted images. They showed no remarkable change on long term follow-up imaging. We propose that a diagnosis of typical VMC could be made after analyzing CT or MR images carefully with good understanding of its pathologic basis, but imaging follow-up is necessary in oncology patients.

Peritoneal implants without ascites: preoperative CT diagnosis in colon carcinoma patients.

We evaluated the preoperative CT findings in 10 patients with colon carcinoma in whom peritoneal metastases had been surgically confirmed. Seven patients lacked ascites. No CT findings suggestive of peritoneal metastasis were observed in two patients without ascites even by retrospective evaluation. A large mass was observed in the cul-de-sac in another. In the remaining four patients, small peritoneal metastases ranging from 8 to 11 mm in diameter were observed at the omentum in two, along the falciform ligament in one, and at both the omentum and the iliac fossa in one; three of these patients had received no prospective diagnosis of peritoneal metastasis prior to the surgery. In patients with advanced colon carcinoma with suspected serosal invasion, the entire peritoneal cavity should be carefully examined and interpreted using CT in order to detect small peritoneal implants even when ascites is absent.

Hepatic peribiliary cysts: multiple tiny cysts within the larger portal tract, hepatic hilum, or both.

PURPOSE: To describe characteristic imaging features of hepatic peribiliary cysts. MATERIALS AND METHODS: Four patients with hepatic cysts in which the radiologic (n = 3) or histologic (n = 1) findings were consistent with peribiliary cysts of the liver (multiple small cysts seen exclusively in the larger portal tract, hepatic hilum, or both at gross examination and dilatations of extramural peribiliary gland at histologic examination) underwent computed tomography (CT) and ultrasound (US). In three patients, CT was performed after drip infusion of cholangiographic contrast material. RESULTS: Contrast material-enhanced CT clearly depicted many tiny cysts along the larger portal veins up to the third- or fourth-order branch (n = 3). US depicted multiple cysts in the echogenic portal tract definitely (n = 2) or equivocally (n = 2). On cholangiographic contrast-enhanced CT scans, cystic areas were located adjacent to or surrounding the bile ducts, and the possibility of biliary dilatation, communication, or both was disproved. CONCLUSION: Hepatic peribiliary cysts can be diagnosed with US and enhanced CT, especially with CT performed after administration of cholangiographic contrast material.

[The evaluation of lung cancers hidden by the mediastinal and hilar shadows on the plain chest film].

We retrospectively evaluated the plain chest frontal radiographs in four cases in which the lung cancers were quite difficult to observe prospectively on plain chest frontal radiographs in spite of the relatively large size of tumors (over 3 cm in diameter). Three of four cases were central-type lung cancers, two squamous cell carcinomas and one adenosquamous cell carcinoma. Since there was no associated atelectasis or obstructive pneumonia in these cases, wall thickening and indistinctness of the lumen of the central bronchi were the significant findings for diagnosis. One case proven to be adenocarcinoma was located in the periphery of S6. A focally increased radiopacity behind the descending pulmonary artery was the only finding to pointed out. Since tumors were not demonstrated directly in the aerated lungs, the condition of the central bronchi as well as the degree radiopacity of the pulmonary artery should be carefully interpreted.

[CT of pulmonary dirofilariasis--differential diagnosis from lung cancer].

We present here four cases of pulmonary dirofilariasis in which histological examination of the surgical specimen showed occlusion of the peripheral pulmonary artery by filariae and formation of a necrotic mass surrounded by reactive inflammation and hemorrhage. Radiological examination showed a solitary pulmonary nodule in three cases and a wedge-shaped consolidation in one case. Although pulmonary nodules in dirofilariasis closely mimic bronchogenic carcinoma on radiographs , it is possible to distinguish them from bronchogenic carcinoma on the basis of the following findings: (1) coexistence of subtle satellite lesions, (2) absence of pleural involvement, (3) fine marginal speculations, and (4) lack of concentric marginal speculations (eccentric speculation). In each case of dirofilariasis, CT showed the peripheral pulmonary artery entering the mass. This finding differentiates this disease from metastatic lung tumor, because in tumor metastasis via the pulmonary arteries, visible vessels are not usually involved.

[Gastric cancer and obstructive uropathy].

In recent 5 years, we have experienced 24 cases of advanced gastric cancer associated with obstructive uropathy. Included were 19 cases of undifferentiated, 3 cases of differentiated and 2 cases of unknown histological type. Obstructive uropathy is diagnosed based on the typical radiological findings such as dilatation and delayed demonstration of the upper collecting systems. Pathologically, undifferentiated type of gastric cancer had tendency to spread infiltrating along the vessels, nerves and the lymphatics without alteration of the ordinary anatomical structures. In such cases, mucosal surface of the urinary tract tended to be spared in spite of extensive tumor invasion. It was proven that several radiological findings were characteristic of urinary tract involvement secondary to gastric cancer. Either thread-like ureteral stricture by IVU or ring-like appearance of the ureter by CT is one of those typical findings. Renal sinus involvement may occur continuously to diffuse retroperitoneal invasion and it appears as a thickened wall of renal pelvis or soft tissue mass directly extending into the fatty tissue of renal sinus by CT. In such cases IVU has less diagnostic ability because of the lack of mucosal destruction. If the urinary bladder is involved, it typically shows chestnut-bur appearance by IVU and diffuse wall thickening by CT. In cases of advanced gastric cancer, particularly in cases of histologically undifferentiated type, CT and IVU images should be carefully interpreted in consideration of the infiltrative art of tumor extension.

[Pulmonary infarction associated with bronchogenic carcinoma].

Pulmonary infarction may be associated with bronchogenic carcinoma. Radiopathological correlation was performed in four patients. There were two cases of squamous cell carcinoma, one case of adenocarcinoma and one case of large cell carcinoma. Infarcts in patients with squamous cell carcinoma were obscured on plain radiographs by a large primary tumor or atelectasis of the affected lobe. Infarcts in adenocarcinoma and large cell carcinoma were clearly demonstrated on plain radiographs; 1 to 2 cm in size, round or polygonal in shape, blurred in margin, and located at the periphery of the same lobe as the primary tumor. Rapid appearance of infarcts was helpful in distinguishing from intrapulmonary metastasis. Invasion of the pulmonary artery, pulmonary vein and bronchial wall in hilar region was thought to be responsible for pulmonary infarction. Pulmonary infarct should be considered in patients with centrally invasive bronchogenic carcinoma, when a small ill-defined opacity appears at the periphery of the involved lobe over a short period.