OSTEOCHONDROMA OF THE PROXIMAL HUMERUS WITH FRICTIONAL BURSITIS AND SECONDARY SYNOVIAL OSTEOCHONDROMATOSIS.

We report a case of multiple hereditary exostosis in a 33-year old patient with clinical symptoms of pain and impression of a growing mass of the left shoulder alerting potential risk of malignant transformation of an osteochondroma. Imaging studies illustrated perilesional bursitis surrounding an osteochondroma of the proximal humerus. Malignant transformation was excluded with MRI. Fragments of the osteochondroma were dislocated in the inflammatory synovial bursa illustrating a case of secondary synovial osteochondromatosis.

Cone beam CT: non-dental applications.

Initially cone beam CT was almost exclusively used to perform dental radiology. However, the first generation CBCT systems were later increasingly used to study sinuses, facial and nose fractures, temporomandibular joints etc. 3D-cephalometric head and neck studies became possible once CBCT systems were available that allowed scanning of the complete head. For this purpose a double rotation technique with stitching of the resulting two data sets was needed. CBCT systems on which the rotation could be stopped were needed to perform dynamic swallow or pharyngography studies. The advent of more powerful high-end CBCT systems led the way to temporal bone and skull base imaging. Finally, high-end "supine" CBCT systems using a "gantry" made small joint musculoskeletal imaging possible. These non-dental CBCT studies gradually replaced conventional X-rays and CT/MDCT studies because they allowed imaging with higher resolution, lower radiation dose and less metal artifacts. In this paper the most important non-dental CBCT indications will be discussed.

Epidermoid cyst of the fourth ventricle: diffusion-weighted and flair MR imaging findings.

Fourth ventricle epidermoid cysts are rare lesions, arising from epithelial remnants at the time of neural tube closure. They are well-defined CT hypoattenuated masses that resemble CSF on all conventional MR imaging sequences. We present a case of a pathological proven less common fourth ventricle epidermoid cyst with special emphasis on the use of FLAIR and EPI-DW imaging sequences in the diagnosis.

Epithelioid hemangioendothelioma of the liver: radiologic-pathologic correlation.

Epithelioid hemangioendothelioma of the liver is a rare vascular tumor with intermediate malignant potential. On imaging studies, the lesion has a solid appearance and may mimic metastatic disease. We present a case in which the morphologic features (multifocal aspect, peripheral location, and capsular retraction) and the clinical history aided in including this entity in the differential diagnosis.