Extrahepatic, nonneoplastic, fat-containing lesions of the abdominopelvic cavity: spectrum of lesions, significance, and typical appearance on multidetector computed tomography

Fat may be noted in a diffuse or focal manner in a variety of nonneoplastic abdominopelvic conditions. The specific signature of macroscopic fat on computed tomography along with the usually characteristic findings of these entities makes the diagnosis of most of these conditions relatively straightforward. In the intestinal tract, the "fat halo sign" usually arises in the context of subacute to chronic bowel wall inflammation. Excess fat in the renal sinus may occur with renal sinus lipomatosis or "replacement lipomatosis of the kidney." Some cases of "pancreatic lipomatosis" may culminate in steatopancreatitis and ultimately neoplastic transformations. "Fibrofatty mesenteric proliferation" is a characteristic feature of Crohn disease. In the setting of the acute abdomen, accurate diagnosis of fat-containing lesions (epiploic appendagitis or omental infarction) from other causes of the acute abdomen is critical. Mesenteric panniculitis is 1 of the causes of the "misty mesentery." Juxtacaval fat deposition is a benign process that has the potential to be confused with more serious conditions. More diffuse fat deposition (abdominal or pelvic lipomatosis) has the potential to become symptomatic by causing mass effect upon the adjacent structures. Fat can also be seen in a variety of postoperative/iatrogenic conditions or abdominal wall/diaphragmatic hernias.     

Spectrum of synovial pathologies: a pictorial assay

The synovium, a specialized vascular tissue, lines the diarthrodial joints, bursae, and tendon sheaths of the body. It helps in nourishment of articular structures. The synovium is affected by a variety of disorders that can be either localized or systemic. Although normal synovium is barely perceptible on magnetic resonance imaging, it provides an excellent imaging modality for the evaluation of pathologic processes involving the synovium. The pathologic processes affecting the synovium include 1 of the following etiologies: inflammatory, infectious, degenerative, traumatic, or neoplastic and tumor-like conditions. In this article, we discuss the magnetic resonance imaging technique and the sequences used in the evaluation of synovial pathologies and review the characteristic imaging findings of specific conditions thus narrowing the differential diagnoses.     

FDG PET/CT appearance of benign pilomatricoma

A 56-year-old patient was referred for FDG PET/CT with a right preauricular lymph node fine-needle biopsy, suggesting poorly differentiated carcinoma and no obvious primary lesion. There was intense FDG uptake in the right preauricular nodule. The node was excised, and formal histology demonstrated a benign pilomatricoma rather than malignancy. Pilomatricoma is uncommon in adults and an unusual cause for marked FDG uptake, likely due to foreign body inflammation. Pilomatricoma can be either benign or malignant. The marked FDG uptake demonstrated in our patient with benign pilomatricoma also suggests that FDG PET cannot reliably grade this rare condition.     

Prophylactic circumferential intraoperative laser retinopexy decreases the risk of retinal detachment after macular hole surgery

Purpose. Pars plana vitrectomy with peeling of the internal limiting membrane is a well-established technique for the treatment of idiopathic macular holes with high success rates. Complications such as retinal tears may result from vitreous incarceration at the sclerotomy sites. Prophylactic laser retinopexy (LR) has recently been shown to decrease incidence of postvitrectomy rhegmatogenous retinal detachment but its efficacy in macular hole repair has not been established. In this study we evaluated the safety and efficacy of prophylactic LR and compared the patients to a control group that did not receive prophylactic treatment. Methods. A retrospective, consecutive chart review was conducted comparing patients who underwent macular hole repair with LR to without LR. Patient demographics were collected and the number and time interval of retinal detachment in the 2 groups were compared. Statistical analysis was conducted between the 2 groups. Results. A total of 144 eyes underwent macular hole repair during the study period. A total of 76 eyes underwent LR and 68 eyes did not undergo LR. There were no significant differences in baseline characteristics between the 2 groups. At 1 year, RD occurred in 1 eye (1.31%) in the LR group and in 8 eyes (8.82%) without LR group (p<0.01). Conclusions. Prophylactic LR decreases the incidence of postoperative retinal detachment a potentially disabling complication of macular hole repair surgery.     

Microarray analysis and biochemical correlations of oxidative stress responsive genes in retinoblastoma

Purpose: Oxidative stress, which refers to the biological damage caused by free radicals produced in excess of innate antioxidant defenses, is indicated in the ocular cancer retinoblastoma (RB). Here we have analysed the differential expression of oxidative stress responsive genes in oxidant-induced RB cells, and in RB tumor tissues. Methods: The study included cultured RB cells, and four RB tumor tissues. The reactive oxygen species (ROS) levels in Y79 cells and the RB tumor induced by hydrogen peroxide were quantified by Dichlorofluorescein (DCF) fluorescence assay. We then analysed the gene expression profile of cultured RB cells induced with hydrogen peroxide (400 μM H(2)O(2) for 8 h) by microarray analysis, and the expression of select genes were validated in Y79 cells and RB tumor tissues by real-time PCR analysis. Results: The oxidant-induced RB tumors showed an average increase in ROS levels of 44-fold compared to induced non-neoplastic donor retina. H(2)O(2)-induced RB cell line showed a 3-fold increase in ROS levels. Microarray analysis on RB cell line induced with H(2)O(2) showed differentially regulated genes involved in cellular processes such as: oxidative stress, angiogenesis, lipid metabolism, cell proliferation, and cell signaling pathways. Several up-regulated genes such as SOD, GPX, CAT, CDC25A, CREBBP, JUN, MMP-2, iNOS, CRYAA, RXRA, ACACB and HMGCR were validated by real-time PCR. These results corroborated with the gene expression analysis in RB tumor tissues. Relating the antioxidant gene expression with the clinico-pathologic features of the tumor tissues, we found that the tumor with invasion of choroid, optic nerve and retinal pigment epithelium, had relatively higher ROS levels and minimal antioxidant gene expression, when compared with the tumor with only choroidal invasion. Conclusions: The study suggests active involvement of redox signaling pathways in the pathogenesis of RB. Consideration of oxidative stress components in the clinical management of RB patients is emphasized.     

A star in the eye: cat scratch neuroretinitis

Neuroretinitis is one of the atypical presentations of Cat scratch disease (CSD). Fundoscopy showed star pattern macular exudates. CSD should be considered in patients who present with blurry vision and typical fundoscopic findings.