Subtle radiographic findings of acute, isolated distal radioulnar joint dislocation.

Distal radioulnar dislocations typically occur in association with fractures of the distal radius and/or ulna. Rare isolated dislocations or subluxations are more difficult to diagnose and are initially missed in up to 50 % of cases. We present two cases of missed isolated volar rotatory dislocation of the distal radioulnar joint. Subtle, overlooked radiographic findings of abnormal radioulnar alignment and ulnar styloid projection are highlighted. The supplemental role of cross-sectional imaging is reviewed. Adequate clinical information, appropriate radiographic technique, and high index of suspicion are necessary for the accurate and timely diagnosis of this rare injury pattern.

Soft-tissue myxomatous lesions: review of salient imaging features with pathologic comparison.

Myxoid soft-tissue lesions are a heterogeneous group of benign and malignant mesenchymal tumors with an abundance of extracellular mucoid material. These lesions may mimic cysts on radiologic evaluation because of the high water content, and histopathologic features also overlap. Benign myxoid lesions include intramuscular myxoma, synovial cyst, bursa, ganglion, and benign peripheral nerve sheath tumor, including neurofibroma and schwannoma. Malignant entities include myxoid liposarcoma, myxoid leiomyosarcoma, myxoid chondrosarcoma, ossifying fibromyxoid tumor, and myxofibrosarcoma. Some syndromes are associated with myxoid soft-tissue lesions, such as Mazabraud syndrome in patients with soft-tissue myxomas and fibrous dysplasia. Certain discriminating features, such as intralesional fat in a myxoid liposarcoma, perilesional edema and a rim of fat in soft-tissue myxoma, and the swirled T2-weighted signal intensity and enhancement pattern of aggressive angiomyxoma, assist the radiologist in differentiating these lesions. The presence of an internal chondroid matrix or incomplete peripheral ossification may suggest myxoid chondrosarcoma or ossifying fibromyxoid tumor, respectively. The entering-and-exiting-nerve sign is suggestive of a peripheral nerve sheath tumor. Communication with a joint or tendon sheath and peripheral enhancement may indicate a ganglion or synovial cyst. This article (a) reviews the magnetic resonance, computed tomographic, and ultrasonographic imaging characteristics of soft-tissue myxomatous lesions, emphasizing imaging findings that can help differentiate benign and malignant lesions; (b) presents differential diagnoses; and (c) provides pathologic correlation.

Two foci of FDG-avid secondary tumoral calcinosis incidentally noted in a patient with small-cell lung carcinoma after PET/CT.

This case report describes intense F-18 fluorodeoxyglucose (FDG) uptake within two foci of secondary tumoral calcinosis, incidentally noted during the workup of small-cell lung cancer. The patient had insulin-dependent diabetes mellitus and secondary hyperparathyroidism as a result of IgA nephropathy.