Stress Fracture of the Capitate

Most capitate fractures occur in association with additional carpal injuries, particularly scaphoid fractures. Isolated fractures of the capitate account for only 0.3% of carpal injuries, and stress fractures are one form of this fracture. We report the case of a 20-year-old male who had a stress fracture of the capitate after serving as an honor guard in the military. Conventional radiographs and computed tomography of the right wrist revealed a minimally displaced fracture line located at the midcarpal aspect of the right capitate. A magnetic resonance imaging scan demonstrates a subarticular capitate fracture with diffuse bone marrow edema, small osteophytes, and irregularity of the midcarpal articular cartilage. We also review the carpal kinematics which possibly caused the stress fracture. Although stress fractures of the capitate are rare, they should also be accounted for with patients who perform repetitive motions of the wrist to a considerable extent.

Radiologic Findings of Renal Schwannoma: A Case Report and Literature Review

Schwannoma is a benign nerve sheath tumor that involves Schwann cells mostly found in the head, neck, posterior mediastinum and extremities. Schwannoma develops rarely in the retroperitoneum; thus, renal schwannoma is extremely uncommon. Differentiation of renal schwannoma from renal cell carcinoma is difficult with radiologic analysis. A few cases of these tumors have been reported in literature, and little has been described regarding imaging appearances. In this study, we present a rare case of a renal schwannoma, resembling renal cell carcinoma, with radiological correlations.

Prediction of high-grade ureteral urothelial carcinoma on CT urography.

OBJECTIVE: To evaluate the correlation between CT urography (CTU) findings and histological grade of ureteral urothelial carcinoma (UUC), and to identify predictors of high-grade UUC. METHODS: CTU images of 73 patients with pathologically proven UUC via nephroureterectomy were independently reviewed by two radiologists for tumour size, tumour location, hydronephrosis grade, periureteral infiltration, presence of enlarged retroperitoneal lymph nodes and tumour enhancement value. Interobserver agreement was assessed with kappa statistics. Histological grade was classified as either low or high according to the WHO 2004 classification system and pathologic T stage was assessed according to the TNM staging system. Binary logistic regression, Spearman correlation analysis and receiver operating characteristic curves were used to evaluate relationships between CTU findings and histological grade. RESULTS: 58 patients had high-grade UUCs and 15 had low-grade UUCs. Among CTU features, only hydronephrosis grade was significantly correlated with high tumour grade for both readers (p < 0.001). Multivariate logistic regression revealed that hydronephrosis of Grade 3 or higher was a significantly independent predictor of high-grade UUC for both readers (p ≤ 0.004). Interobserver agreement was excellent for hydronephrosis grade (к = 0.862). With the cut-off value of hydronephrosis Grade 3, the sensitivity, specificity and area under the curve for predicting high-grade UUC were, respectively, 88%, 79% and 0.830 for reader 1 and 86%, 80% and 0.763 for reader 2. CONCLUSION: Hydronephrosis of Grade 3 or higher on CTU may be predictive of high-grade UUC. Advances in knowledge: Radical surgery should be considered for UUC causing hydronephrosis of Grade 3 or higher on CTU, even in small tumours without periureteral infiltration.

Progressive Transformation of Germinal Centers in Presacral Space: MRI Findings and Literature Review

Progressive transformation of germinal centers (PTGC) is an atypical feature seen in lymph nodes with unknown pathogenesis. PTGC most commonly presents in adolescent and young adult males as solitary painless lymphadenopathy with various durations. Cervical nodes are the most commonly involved ones while involvements of axillary and inguinal nodes are less frequent. PTGC develops extremely rarely in other locations. We report a rare case of solitary mass present in the presacral space. The mass as subsequently proven to be PTGC. To the best of our knowledge, PTGC in the presacral space has not been previously reported in the literature.