Jane E. Benson

MR imaging of pediatric cerebral abnormalities

Surgicalne hundred sixteen magnetic resonance (MR) imaging studies from 105 pediatric patients with a variety of cerebral abnormalities were reviewed to determine the diagnostic efficacy of MR in the pediatric population. All subjects tolerated the MR procedure well, although sedation was necessary for younger children. Compared with CT, MR proved to be advantageous in detection and characterization of the pathology in 23 of 105 patients, especially when the abnormality was located along the base of the brain and midline, or when it involved primarily the white matter. Intracranial calcification was the one abnormality not detected with MR although dense calcifications could be seen as areas of low signal intensity. Some characteristics of various pathological entities were compared in an attempt to differentiate among abnormalities in the same anatomical location: craniopharyngioma from optic chiasm and hypothalamic glioma, cystic glioma from arachnoid cyst, and chronic subdural hematoma from subdural hygroma. The lack of ionizing radiation in MR is of particular interest in pediatric neuroradiology since radiation is of special concern in the young age group.

Lymphonodular hyperplasia of the colon as a pathologic finding in children with lower gastrointestinal bleeding

The serious implication of gastrointestinal blood loss in children is well recognized; however, the significance of lymphonodular hyperplasia of the colon (LNHC) as a pathologic finding in this group of children is unclear. We reviewed the records of 95 children, ages 2-48 months, who were referred to our clinic with a history of hematochezia. Proctosigmoidoscopy was performed on 65 of them. Twenty children (31%) examined proctosigmoidoscopically were found to have LNHC, with no other identified source of bleeding. Clinical histories, endoscopic findings, and colonic biopsy specimens from the LNHC group were examined. Clinical presentation of patients in this group was not distinctive. LNHC was most prominent in the distal colon and rectum and was endoscopically characterized by friability (13/20) and ulceration (3/20). Characteristics of biopsy specimens from children with LNHC were than compared with tissue obtained from an age-matched control population and children with colitis. Biopsy specimens from children with LNHC contained increased numbers of lymphoid follicles and larger follicles than those from the control group. Specimens also contained mucosal inflammation and epithelial thinning and ulceration overlying enlarged follicles. We conclude that LNHC is a frequent proctosigmoidoscopic finding in children evaluated for lower gastrointestinal bleeding. The endoscopic and histologic appearance of these lesions would suggest that LNHC is not a normal finding and represents a potential source of rectal bleeding in children.

MR imaging of the skull base

Fifty-four patients with abnormalities primarily involving the base of the skull were evaluated by magnetic resonance (MR) imaging. The results were compared with information obtained by other radiologic studies, primarily X-ray CT. On MR imaging, better anatomic definition of soft tissues in the deep compartments of the nasopharynx was achieved through the high level of tissue contrast discrimination and lack of bone artifacts. The parapharyngeal fat plane, separating pterygoid from pharyngeal musculatures, was consistently demonstrated. However, the inability of MR to image compact bone proved to be a major drawback where bony detail was required. In general, MR imaging demonstrated 100% sensitivity to abnormalities involving the posterior compartment (clivus and craniovertebral junction) and was least valuable in the evaluation of the anterior compartment (orbits, cribiform plate, and sinuses).

Mr imaging of brain stem gliomas

Magnetic resonance (MR) and CT examinations of 26 patients with the established or clinically suspected diagnosis of brain stem glioma were reviewed. Eleven tumors were seen on both MR and CT. The entire extent of the abnormality was better outlined on MR, although CT was more advantageous in demonstrating cystic components and calcium deposition. Magnetic resonance and CT depicted focal intratumoral hemorrhage equally. Magnetic resonance was found to be particularly suitable to follow up the progression or regression of the disease. Of particular interest were two patients with evidence of aqueductal obstruction but normal CT appearance of the midbrain; the causative abnormality, believed to be a glioma, was clearly shown by MR imaging. In nine patients the normal appearance was helpful to exclude the possibility of a brain stem glioma. Thus far, results have shown 100% sensitivity (true positive ratio) and specificity (true negative ratio) with MR in the evaluation of brain stem gliomas. It is concluded that MR imaging should be the examination of choice and could be the definitive screening procedure in patients with suspected brain stem glioma.

Primary amyloid tumor of the lacrimal gland: CT findings.

We present a rare case of primary amyloid tumor originating in the lacrimal gland. The computed tomographic findings are similar to those of an orbital angioma, showing an enhancing soft tissue mass with multiple calcifications simulating phleboliths.

Intestinal Malrotation and Omental Cyst Presenting as Fetal Ascites

The etiology of ascites varies depending on the age of the individual. Isolated fetal ascites in the absence of generalized hydrops is a particularly uncommon problem. Causes of fetal ascites include genitourinary tract disorders, cardiac disorders, chromosomal abnormalities, infections, metabolic disorders, tumors, and hepatic and gastrointestinal disorders (1). This is a report of fetal ascites associated with intestinal malrotation and omental cyst in an otherwise healthy infant.

Unusual case of hypothyroidism in an infant with hepatic hemangioma.

I nfantile hepatic hemangiomas (IHHs) are the most common tumors of infancy and occur in approximately 5% of children younger than age 1 year (1–4). Hemangiomas are postulated to arise from dysregulated angiogenesis (3,5), and vascular endothelial growth factor (VEGF) may play a role in the development of these tumors; thus, serum levels of VEGF can be used for diagnostic and therapeutic guidance (2). VEGF levels could be different in the proliferative versus involuting hemangiomas (6). A recently published study has shown that corticosteroids can suppress VEGF-A production by hemangioma-derived stem cells, thereby inhibiting vasculogenesis (7). Hepatic hemangioma can occur at all ages, diagnosed most commonly in individuals ages 30 to 50 years. Infants develop a type of hepatic hemangioma called benign hepatic hemangioendothelioma; these IHHs have also been detected prenatally in a growing fetus (8,9). IHHs are the most common benign neoplasm of hepatic vascular neoplasms of infancy; most are small and clinically silent. Symptomatic patients present in the first few months of age with a history of abdominal enlargement with or without other symptoms or signs related to their unique physiology. Extensive multifocal or diffuse hemangiomas may manifest as cardiac failure secondary to high-volume shunting, hypothyroidism, jaundice, and abdominal compartment syndrome. Hepatic failure is uncommon except after poorly performed embolization. Treatment of symptomatic IHH is aimed toward tumor suppression by the administration of corticosteroids, b-blockers, vincristine, and, in some instances, endovascular or surgical intervention. (10,11) Currently, first-line treatment consists of b-blocker (propranolol) therapy. Embolization may be required for severe high-output cardiac overload, only if pharmacotherapy is unsuccessful. Several groups have reported the development of an unusual form of consumptive hypothyroidism in infants with IHH (12–15). The hemangiomas in these infants express excessive amounts of type 3 iodothyronine 5-deiodinase (D3). This enzyme is considered an inactivating enzyme because it converts T4 and T3 to