Use of the International Society for the Study of Vascular Anomalies (ISSVA) classification system has been strongly recommended in recent years because of the need for separate therapeutic measures for patients with vascular tumors and malformations. In the ISSVA classification system, vascular tumors, which are neoplastic, are distinguished from vascular malformations, which are caused by vascular structural anomalies and are not neoplastic, on the basis of the presence or absence of neoplastic proliferation of vascular endothelial cells. It is important that radiologists be familiar with the development, diagnosis, and treatment of vascular tumors and malformations, especially the imaging features of low- and high-flow vascular malformations. Some vascular tumors and malformations develop in isolation, whereas others develop within the phenotype of a syndrome. Syndromes that are associated with vascular tumors include PHACE syndrome. Syndromes that are associated with vascular malformations include Sturge-Weber, Klippel-Trénaunay, Proteus, blue rubber bleb nevus, Maffucci, and Gorham-Stout syndromes, all of which demonstrate low flow, and Rendu-Osler-Weber, Cobb, Wyburn-Mason, and Parkes Weber syndromes, all of which demonstrate high flow. Because imaging findings may help identify such syndromes as systemic, it is important that radiologists familiarize themselves with these conditions.

The aim of the present study was to investigate the significance of appendicoliths as an exacerbating factor of acute appendicitis using multivariate analysis. A total of 254 patients with pathologically proved acute appendicitis were enrolled in this retrospective study (male, 51 %; mean age, 40.1 years; range, 15-91 years). Two radiologists performed a consensus evaluation of preoperative CT images for the presence of appendicoliths in consensus. When there were appendicoliths, they assessed the number and location of appendicoliths, and measured the longest diameter of the largest appendicolith. Pathological diagnosis was used for the reference standard. The relationships of appendicoliths to gangrenous appendicitis and to perforated appendicitis were each assessed with multiple logistic regression models, which were adjusted for demographic and clinical characteristics of patients. Significant relationships were identified between gangrenous appendicitis and the presence of appendicoliths (OR, 2.2; 95 % CI, 1.2-4.0), the largest appendicolith more than 5 mm in the longest (OR, 3.0; 95 % CI, 1.6-5.7), and location of an appendicolith at the root of the appendix (OR, 2.0; 95 % CI, 1.1-3.8). Among the CT characteristics, the location of an appendicolith at the root of the appendix only showed significant relationship with perforated appendicitis (OR, 4.5; 95 % CI, 1.4-15.4). Size of the largest appendicolith and location of appendicoliths at the root of the appendix are exacerbating factors of acute appendicitis.

Children with cancer are at increased risk of life-threatening emergencies, either from the cancer itself or related to the cancer treatment. These conditions need to be assessed and treated as early as possible to minimize morbidity and mortality. Cardiothoracic emergencies encompass a variety of pathologies, including pericardial effusion and cardiac tamponade, massive hemoptysis, superior vena cava syndrome, pulmonary embolism, and pneumonia. Abdominal emergencies include bowel obstruction, intussusception, perforation, tumor rupture, intestinal graftversus-host disease, acute pancreatitis, neutropenic colitis, and obstructive uropathy. Radiology plays a vital role in the diagnosis of these emergencies. We here review the clinical features and imaging in pediatric patients with oncologic emergencies, including a review of recently published studies. Key radiological images are presented to highlight the radiological approach to diagnosis. Pediatricians, pediatric surgeons, and pediatric radiologists need to work together to arrive at the correct diagnosis and to ensure prompt and appropriate treatment strategies.

Ultrasound is mainly useful for excluding purulent lymphadenopathy while CT is a useful diagnostic tool for differentiating KD from CL, especially in patients with incomplete KD, who present with prominent cervical lymphadenopathy and other equivocal principal findings.