CT imaging spectrum of infiltrative renal diseases.

Most renal lesions replace the renal parenchyma as a focal space-occupying mass with borders distinguishing the mass from normal parenchyma. However, some renal lesions exhibit interstitial infiltration-a process that permeates the renal parenchyma by using the normal renal architecture for growth. These infiltrative lesions frequently show nonspecific patterns that lead to little or no contour deformity and have ill-defined borders on CT, making detection and diagnosis challenging. The purpose of this pictorial essay is to describe the CT imaging findings of various conditions that may manifest as infiltrative renal lesions.

The gamut of primary retroperitoneal masses: multimodality evaluation with pathologic correlation.

The retroperitoneum is a large space where primary and metastatic tumors grow silently before clinical signs appear. Neoplastic retroperitoneal diseases may be solid or cystic, primary or secondary and range from benign to aggressive in behavior. Retroperitoneal neoplasms are notable for their widely disparate histologies. The solid primary retroperitoneal neoplasms are extremely uncommon and can be classified based on their tissue of origin into three main categories: mesodermal tumors, neurogenic tumors, and extragonadal germ cell tumors. These tumors can grow to a large size before clinical symptoms occur or become palpable. When symptoms do occur, they are nonspecific. The majority of these masses are malignant and imaging plays a pivotal role in the detection, staging, and pre-operative planning. Benign and malignant masses should be distinguished whenever possible to avoid unnecessary surgical procedures. Macroscopic fat, calcification, necrosis, vascularity, and neural foraminal widening are common imaging features helping for tumor differentiation. Meticulous cross-sectional imaging can triage the patient to the most appropriate therapy. Tumor morphology dictates imaging character, and biologic activity is reflected by positron emission tomography (PET). Complete surgical excision with tumor free margins is essential for long-term survival. Biopsy should be performed in consultation with surgical oncology to avoid complicating curative surgery. This pictorial essay illustrates the spectrum of multidetector computed tomography (MDCT) imaging findings in common and uncommon primary retroperitoneal masses, with an emphasis on cross-sectional imaging features for an adequate tumor characterization and staging.

Delayed Splenic Rupture; Normal Appearing Spleen on the Initial Multidetector Computed Tomography (MDCT) Can Sometimes Be Misleading.

INTRODUCTION: Delayed splenic rupture (DSR) is an unusual outcome following blunt abdominal trauma. Although DSR is defined as bleeding more than 48 hours after blunt trauma in a previously hemodynamically stable patient, a review of the reported cases in the literature shows that in almost all of the cases the initial CT imaging revealed some form of damage to the spleen. CASE PRESENTATION: Here we describe an extremely rare condition in a case that presented with a DSR following blunt trauma and had a normal appearing spleen in the initial post trauma MDCT scan. CONCLUSIONS: DSR is a serious consequence of trauma and is associated with a significantly higher mortality rate compared with the overall mortality for acute splenic injuries. A High index of suspicion along with the liberal serial utilization of the imaging studies are the essential elements for early detection of DSR. We propose that DSR be considered as a differential diagnosis in patients presenting with hemodynamic instability late post trauma, even when the immediate post trauma MDCT scan has shown a normal appearing spleen. We suggest that every patient with a high impact injury or injuries to peri-splenic organs should have a repeat MDCT scan 2 - 3 days post trauma or before the patients is discharged from hospital.

Atypical hemorrhagic presentation of a fourth ventricle subependymoma: case report.

OBJECTIVE: To present a case of a fourth ventricle subependymoma (SE) with a spontaneous acute subarachnoid intra-cisternal bleeding. METHODS: A 33-year-old man was admitted with 5 days history of oppressive occipital headache and neck pain without additional neurological focus. Unenhanced computed tomography (CT) scan demonstrated an isointense mass located in the fourth ventricle with a spontaneously hyperdense acute extratumoral hemorrhage in the cisterna magna. Contrast-enhanced magnetic resonance imaging (MRI) revealed a well-delimitated non-enhanced tumor, hypointense on T1-weighted and hyperintense on T2-weighted images, involving the floor of the fourth ventricle and extending caudally into the cervical spinal canal via foramen magnum. RESULTS: Intraoperative, a large blood clot was removed and a macroscopically hypovascularlesion was completely excised from the right lateral recess and the floor of the fourth ventricle. Intra and postoperative immuno-histopathological examination revealed a SE. The patient has a normal postoperative course and was discharged in the fifth postoperative day. A 10-month postoperative MRI study confirmed a complete tumor resection. CONCLUSION: Symptomatic SEs should be surgically treated emphasizing the urgency in the presence of hemorrhage. The interest of this case is to demonstrate that infratentorial SEs although extremely rare, might present with acute subarachnoid bleeding.