Computed tomography of fibrous dysplasia

OBJECTIVE: Fibrous dysplasia (FD) is an uncommon, but important lesion affecting the jaws. The aim of this study was to reveal its presentation on computed tomography (CT) in a consecutive series of cases. METHODS: The files of the Department of Oral and Maxillofacial Surgery of Hong Kong University between 1989 and 2000 were reviewed for cases of FD. RESULTS: Of the ten cases investigated by CT, two were rejected because of extensive biopsy or surgery before the CT investigation. Seven of the remaining eight cases were Chinese and one was Indian. The mandible and maxilla were equally affected. The cortex was generally intact, except when adjacent to the teeth in the maxilla. The margins were generally poorly-defined, but well-defined on at least some sections of each maxillary case. Five cases were extensive, affecting or nearly affecting the whole hemi-mandible or hemi-maxilla to the midline. All cases displayed expansion, which was fusiform in the mandible and an enlargement of the normal contour in the maxilla. The maxillary antrum was completely obturated in three maxillary cases; one displayed a rounded dome-shaped lesion more suggestive of a benign neoplasm. The orbital floor was displaced in three cases; one of those cases presented with proptosis. All maxillary cases extended back to the pterygoid process, but did not displace it. The "bone windows" of eight cases generally displayed a "ground-glass" pattern; one also displayed cyst-like radiolucencies. The soft tissue window, which depicts mineralized tissue as "white", showed that five cases were completely mineralized. CONCLUSION: CT can be used to determine the extent, specific dimensions and radiodensity of FD.     

Computed tomography of craniofacial fibrous dysplasia

We present five patients with fibrous dysplasia: two monostotic affecting the maxilla, two craniofacial, and one disseminated. Computed tomography was extremely useful for demonstrating the gross bony changes as well as anatomical detail with preservation of the cranial exit foramina. These findings correlate with the lack of significant neurological deficits. The information obtained on CT may be useful for cosmetic reconstructive surgery and debulking procedures.     

Computed tomography demonstration of subarachnoid-pleural fistula

A persistent left pleural effusion caused diagnostic difficulty in a young girl, 2 years after a road accident had rendered her paraplegic. Eventually, after instillation of a contrast medium into the pleural fluid, computed tomography showed a fistulous communication between the subarachnoid and pleural spaces at the level in the dorsal spine where trauma had occurred.     

Computed tomography demonstration of unusual diffuse metastatic calcification secondary to renal failure

We report the computed tomography findings in an unusual case of diffuse metastatic calcification secondary to renal failure.     

Computed tomography demonstration of traumatic suburothelial hemorrhage

We report a patient with the characteristic findings of suburothelial hemorrhage secondary to blunt trauma that was initially detected by computed tomography.     

Computed tomography of renal lymphoma

The CT studies of 29 patients with renal or perirenal lymphoma were retrospectively reviewed. Four patterns of disease were identified. Seventeen of 29 patients (59%) had bilateral renal masses. Only seven of these patients had associated enlarged retroperitoneal lymph nodes. Eight patients (28%) had single renal or perirenal lesions adjacent to or contiguous with bulky retroperitoneal lymphadenopathy. Three patients had infiltration of the perirenal space without significant renal parenchymal involvement, and one patient had a solitary renal mass. No patients in this series had diffuse involvement of the kidney without a focal mass. Renal involvement with lymphoma should be considered in any patient who develops multiple homogeneous solid renal or perirenal masses, even in the absence of other retroperitoneal disease.     

Computed tomography of renal sarcoidosis

Radiographic evidence of renal involvement by sarcoidosis is usually demonstrated as nephrocalcinosis or nephrolithiasis. We present a case of renal sarcoidosis manifested as noncalcified masses on contrast enhanced CT.     

Computed tomography of renal metastases

The CT manifestations of renal metastases from nonurinary tract carcinomas were evaluated in five autopsy-proven cases. Three cases resembled renal inflammatory disease or renal cysts. The wide variety of CT manifestations of renal metastases underscores the need to bear renal metastases in mind when renal abnormalities are observed in any case of advanced malignancy.     

Computed tomography of renal aspergillosis

The CT and sonographic findings of a case of localized, invasive aspergillosis of the kidney are presented.     

Computed tomography in renal lymphoma

The computed tomographic characteristics of 15 cases of renal lymphoma were evaluated. Initially the renal lesions are nodular but become confluent as the tumor progresses. In histiocytic and Hodgkin lymphoma, lesions can have the same attenuation values as normal renal parenchyma on noncontrast scans but less than normal parenchyma after contrast medium administration. Computed tomography is also useful in evaluating prognosis and response to therapy in renal lymphoma. Contrast material should be given if possible for evaluation of these lesions.     

Computed tomography demonstration of a fat-fluid level in tuberculous chylous ascites

The occurrence of fat-fluid levels in ascites, although rare, is pathognomic of chylous ascites. The ultrasound and CT scan findings of a fat-fluid level in the ascitic fluid of a patient with abdominal tuberculosis are described here. Recognition of this important sign, in conjunction with other ancillary findings of abdominal tuberculosis, assist in establishing the correct diagnosis. Anti-tuberculous chemotherapy suffices in treating the condition, thus obviating the need for surgical intervention.     

Computed tomography manifestations of renal hemangiopericytoma

Renal hemangiopericytoma (HPC) is a rare tumor. There are no unique radiological findings that can reliably aid in its preoperative diagnosis. A 60-year-old Japanese male was admitted for an abdominal mass. Ultrasound revealed a heterogeneous hyperechoic mass. Computed tomography (CT) showed a heterogeneous mass and tumor vascularity by a precontrast and dynamic study with maximum intensity projection (MIP) and volume-rendering technique (VRT). Radical nephrectomy was performed, and the histopathogic diagnosis revealed renal HPC.     

Computed tomography of primary renal osteosarcoma

Primary renal osteosarcoma, a rare malignancy, was diagnosed preoperatively based on its unusual imaging features. The CT demonstration of a peripherally located renal mass containing ossification suggests the diagnosis of renal osteosarcoma. This diagnosis is clinically significant due to the poor prognosis of patients with this tumor even when surgically resectable.