Conditional activation of Pik3ca(H1047R) in a knock-in mouse model promotes mammary tumorigenesis and emergence of mutations.

Oncogenic mutations in PIK3CA, which encodes the phosphoinositide-3-kinase (PI3K) catalytic subunit p110α, occur in ∼25% of human breast cancers. In this study, we report the development of a knock-in mouse model for breast cancer where the endogenous Pik3ca allele was modified to allow tissue-specific conditional expression of a frequently found Pik3ca(H1047R) (Pik3ca(e20H1047R)) mutant allele. We found that activation of the latent Pik3ca(H1047R) allele resulted in breast tumors with multiple histological types. Whole-exome analysis of the Pik3ca(H1047R)-driven mammary tumors identified multiple mutations, including Trp53 mutations that appeared spontaneously during the development of adenocarinoma and spindle cell tumors. Further, we used this model to test the efficacy of GDC-0941, a PI3K inhibitor, in clinical development, and showed that the tumors respond to PI3K inhibition.

Current concepts and controversies in imaging of renal cystic diseases.

Renal cystic disease compromises a diverse group of inherited and acquired entities. This article reviews the clinical, pathologic, and radiologic findings of eight renal cystic diseases. For each entity, the current concepts of pathogenesis and pathophysiology are discussed. When appropriate, controversies concerning terminology, management, and malignant potentials are addressed. Renal cystic diseases that are discussed include autosomal dominant and autosomal recessive polycystic kidney disease, medullary sponge kidney, medullary cystic disease, multicystic, dysplastic kidney, von Hippel-Lindau disease, acquired cystic kidney disease, and tuberous sclerosis.

Renal cystic diseases.

Renal cystic disease comprises a mixed group of heritable, developmental, and acquired disorders. Because of their diverse etiology, histology, and clinical presentation, no single scheme of classification has gained acceptance. Conditions include autosomal dominant polycystic kidney disease, acquired renal cystic disease, medullary sponge kidney, autosomal recessive polycystic kidney disease, multicystic dysplastic kidney, medullary cystic disease, tuberous sclerosis, cysts of the renal sinus, and von Hippel-Lindau's disease. An awareness of the pathology of each cystic disease is helpful in the understanding of the corresponding radiological images. Imaging techniques used in evaluating renal cystic disease include intravenous urography, sonography, CT, MRI, nuclear medicine, and renal angiography. Many types of cystic disease show similar imaging features. Meticulous attention to subtle radiological findings is therefore essential for reaching a correct diagnosis. Imaging features requiring analysis include whether the cysts are unilateral or bilateral, renal size and functional status, cyst distribution in the kidneys, and the presence of hemorrhagic and calcified renal cysts, solid renal masses, renal sinus cysts, and cysts in adjacent organs. Radiological findings should be carefully correlated with clinical features such as patient age, family history, symptoms, physical findings, and renal functional status before a diagnosis is attempted.

CT diagnosis of splenic vein occlusion: imaging features, etiology and clinical manifestations.

BACKGROUND: Previous reports have described the computed tomographic (CT) appearance of collateral veins following splenic vein occlusion (SVO). This retrospective study was performed to determine the etiology, clinical manifestations, and accuracy of CT diagnosis in patients with this entity. METHODS: A computer search of radiology reports for a 1-year period found 52 patients with SVO diagnosed by absence of visualization of the splenic vein accompanied by the formation of the expected perigastric collateral veins. Clinical data were reviewed for sequela of SVO and clinical impact of the diagnosis. RESULTS: In 12 cases, other studies confirmed the CT diagnosis of SVO. In no case was the CT diagnosis proved to be incorrect by other imaging studies. Angiographic records found five additional cases with SVO not diagnosed by CT, but two of five had convincing CT evidence of SVO noted upon reevaluation by the authors. Review of clinical data showed heme-positive stool in six, of which three had significant gastrointestinal hemorrhage. Splenic infarction occurred in two cases. CONCLUSIONS: Our data indicate that SVO is more common than previously suspected and usually remains clinically silent, but CT appears to be highly specific and fairly sensitive for its diagnosis.

Volume of the spleen in children as measured on CT scans: normal standards as a function of body weight.

OBJECTIVE: The purpose of this study was to develop standards for the normal volume of the spleen in children as measured on CT scans. SUBJECTS AND METHODS: CT scans were used to measure the volume of the spleen in 48 children (30 boys and 18 girls), 1 day to 18 years old (mean and median ages were 8.2 and 7.8 years, respectively). Children who had underlying malignant tumors, infection, hematologic diseases, or other conditions that could alter splenic size were excluded. The area of the spleen on each axial section was determined by tracing its outline on the CT monitor and measuring the area of the region of interest. The area of the spleen on each section was multiplied by the slice thickness to calculate the volume of the spleen for each section. The total volume of the spleen was then determined by adding the individual volumes for each of the sections through the spleen. This method of calculating splenic volume has been validated in previous studies in adult subjects. The volume of the spleen was analyzed as a function of both body weight and age. RESULTS: The volume of the spleen correlated better with body weight than with age. The best regression model (r = .85) was a linear relationship as follows: splenic volume (cm3) = 0.7 + [4.6 x weight (kg)]. Using these data and a regression model, we generated standards for normal volume of the spleen as a function of body weight (with 95% tolerance intervals). CONCLUSION: We have developed CT standards for normal splenic volume in children. These standards can be used to objectively measure the size of the spleen in children who have clinically suspected splenomegaly.

Ilio-psoas abscess in neonates.

We report two cases of primary ilio-psoas abscess in neonates diagnosed by CT and sonography. Ilio-psoas abscess is extremely uncommon in this age group.