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Biomedical subjects

J C Leonidas

Publications and source records attributed to J C Leonidas.

At least 19 recordsLinked to original sources
PubMed1991

Magnetic resonance imaging in the diagnosis of adolescent colorectal carcinoma.

A 14-year-old girl presented with a large abdominal mass, thought to be an ovarian tumor on the basis of clinical and sonographic findings. MRI correctly suggested a primary colonic neoplasm. At operation, ovarian involvement was found to be secondary to metastatic signet ring cell adenocarcinoma of the colon, an extremely rare malignancy in this age group. Low index of suspicion for this tumor in children and adolescents results in advanced disease at diagnosis and poor prognosis. Early imaging with MRI is recommended when the nature of pelvic disease in children remains obscure.

Adenocarcinoma, Mucinous↗
PubMed1991

Granulomatous hepatitis in cat-scratch disease. Ultrasound and CT observations.

A male two year old was admitted to the hospital with a one month history of fever. The physical examination was unrevealing. Abdominal ultrasound revealed multiple, circumscribed regions of low attenuation in the liver and a parapancreatic mass. Laparotomy and biopsy revealed multiple nodules in the liver. The histopathologic findings indicated the child had cat-scratch disease, which resolved with administration of gentamycin sulfate.

Cat-Scratch Disease↗
PubMed1991

Sonographic abnormalities of the thyroid gland in longterm survivors of Hodgkin disease.

We studied the thyroid gland in 18 long term survivors of Hodgkin Disease, all of whom received radiation therapy (2400-4000 cGy, mean 3434). Evaluation included clinical examination, thyroid function tests, ultrasound, as well as selective use of nuclear scintigraphy. The time interval post radiation was 1-16 years (mean 6.4 years). Clinical evaluation and thyroid function tests were insensitive in detecting abnormalities and most nodules were non palpable. Ultrasound detected abnormalities in 16 patients (89%) including diffuse atrophy (n = 6), solitary nodules (n = 4), multiple nodules (n = 5) and gland heterogeneity with calcification in one patient. Cold nodules on nuclear scintigraphy (n = 4) were subjected to biopsy. Multiple foci of papillary carcinoma were found in one patient. There was a tendency for nodules to increase in number as the post radiation interval also increased. We recommend frequent sonographic evaluation and early suppression of thyroid stimulation in an attempt to arrest the development of neoplastic changes.

Adolescent↗
PubMed1991

Midgut volvulus in infants: diagnosis with US. Work in progress.

The authors present findings from ultrasound (US) studies that can alert sonologists to the possibility of midgut malrotation complicated by volvulus in neonates and infants. A fluid-filled, distended duodenum seen at US examination in infants is a nonspecific sign of duodenal obstruction, as well as one of the signs of midgut malrotation. In addition, dilated, thick-walled bowel loops, mainly to the right of the spine, and peritoneal fluid were found at abdominal US examinations of three infants with midgut malrotation complicated by volvulus. In one infant with uncomplicated midgut malrotation, only signs of duodenal obstruction were present. The findings at US of duodenal obstruction associated with thickened bowel loops to the right of the spine and peritoneal fluid should lead the sonologist to suspect midgut malrotation complicated by volvulus, a potentially fatal condition, and an upper gastrointestinal series should then be performed to confirm the diagnosis.

Duodenal Obstruction↗
PubMed1991

Parotid enlargement in children seropositive for human immunodeficiency virus: imaging findings.

We investigated the clinical, immunologic, and imaging features of parotid enlargement in 10 children seropositive for human immunodeficiency virus (HIV) who were infected prenatally. In seven patients, sonography revealed many small hypoechoic areas suggestive of lymphoid infiltration. In three older children, large anechoic areas suggesting lymphoepithelial cysts were present. The lesions probably represent generalized lymphoid infiltration akin to pulmonary lymphoid hyperplasia, although only two of our patients had radiologic evidence of pulmonary lymphoid hyperplasia. Four of five of the children with parotid enlargement who had immunologic studies were phenotypically HLA-DR5, an immunophenotype associated with improved immune response, occurring in less than one in four in the normal population. This suggests that painless parotid enlargement may be a good prognostic sign in HIV-seropositive children. Parotid enlargement was found in 10 HIV-positive children from 6 months to 11 years old. All except one were infected prenatally.

Antibodies, Viral↗
PubMed1990

A rational approach to the diagnosis of hypertrophic pyloric stenosis: do the results match the claims?

The currently accepted premise that the diagnosis of hypertrophic pyloric stenosis (HPS) should be made on clinical grounds, with ultrasound (US) and upper gastrointestinal series (UGIS) reserved for those with a negative clinical examination, was tested. Variable clinical skills of initial examiners, including pediatric surgeons, made abdominal palpation no more sensitive or specific than US or UGIS. For those with a negative clinical examination, proceeding directly to a UGIS will result in monetary savings, especially if good clinical performance decreases the probability of HPS among those without palpable pyloric "tumors." The benefits of a "US first" approach (no radiation, better patient and parent acceptance, no contrast medium) are less apparent but no less important and increase as clinical experience declines and performance of US improves. Criteria for the clinical or sonographic diagnosis of HPS should be kept strict to avoid false-positive results; false-negatives and other causes of vomiting should be identified by UGIS.

Diagnosis, Differential↗
PubMed1990

Lymphoma of the mediastinum and neck: evaluation with Ga-67 imaging and CT correlation.

The role of gallium-67 in the differentiation between active disease and fibrotic changes in patients with childhood lymphoma involving the mediastinum and neck was evaluated prospectively. Ga-67 imaging and computed tomography (CT) were correlated with clinical findings at the time of initial presentation and follow-up in 19 patients. Both modalities enabled detection of active disease on all occasions, but CT results were false-positive for residual disease in 10 patients (53%), whereas Ga-67 imaging results were false-positive in only one patient (5%). Neither modality, however, proved accurate in patients with rebound thymic hyperplasia. Ga-67 imaging is a useful tool for assessing response to therapy in children with lymphoma of the mediastinum and neck.

Adolescent↗
PubMed1990

Clinical activities of pediatric radiologists in the United States and Canada: 10-year follow-up.

The members of the Society for Pediatric Radiology were surveyed in 1989 about their involvement with newer imaging modalities. Results were compared with those obtained in a similar study performed 10 years earlier. The performance and monitoring of imaging studies increased dramatically, with most respondents now being involved with ultrasound (US) and computed tomography (CT), and almost one-half involved with magnetic resonance (MR) imaging. When equipment became available, pediatric radiologists were quicker to assume control of MR imaging than US and CT. In most large pediatric centers, imaging with all current modalities and of all organ systems has become the responsibility of pediatric radiologists. These findings are in contrast to those obtained in 1979, when pediatric imaging practices primarily consisted of conventional radiography and fluoroscopy.

Canada↗
PubMed1990

Congenital neuroblastoma: evaluation with multimodality imaging.

The authors retrospectively evaluated 12 patients with congenital (neonatal) neuroblastoma to assess the utility of newer imaging modalities. Findings at prenatal ultrasound (US), performed in four patients, were nonspecific (hydramnios and hydrops fetalis) in two and consistent with a suprarenal mass (one solid, one cystic) in the other two. Postnatal US helped accurately detect adrenal tumors (solid or complex, with one exception) but was less accurate in the diagnosis of metastatic disease to the liver. Computed tomography accurately depicted all primary tumors and liver metastases. Magnetic resonance (MR) imaging helped establish the correct diagnosis in three patients. This study again confirmed the benign course of neonatal neuroblastoma, with 50% of the patients classified with stage IV-S disease and two deaths occurring in the series, both due to complications. Therefore, aggressive diagnostic imaging is less desirable, and US is therefore very useful, despite its limitations. The prenatal detection and solid appearance of a suprarenal mass makes the diagnosis of neuroblastoma very likely, as does the presence of liver lesions. In the absence of these characteristic findings, US should be repeated to exclude adrenal hemorrhage. MR imaging seems to be a good alternative in some instances.

Adrenal Gland Neoplasms↗
PubMed1989

Microcolon in the absence of small bowel obstruction in the newborn.

Microcolon is a manifestation of intestinal obstruction in utero, and in the overwhelming majority of cases it accompanies low small bowel obstruction. Two cases of congenital abdominal masses, an ileal duplication, and a cystic mesenchymal hamartoma of the liver caused microcolon although the bowel was intrinsically normal. Bowel compression in utero may also lead to neonatal microcolon.

Adult↗
PubMed1988

Aggressive neuroblastoma simulating Wilms tumor.

Solid intrarenal neoplasms in children are usually Wilms tumors. Occasionally, however, a neuroblastoma appears to be intrarenal. In six cases where this phenomenon was observed, the histologic findings of each tumor were identical: undifferentiated neuroblastoma. In each case the child's condition rapidly and progressively deteriorated. These six cases demonstrate the possibility that intrarenal origin or extension of neuroblastoma may be confused with Wilms tumor.

Diagnosis, Differential↗