Iron overload in reticuloendothelial systems of pediatric oncology patients who have undergone transfusions: MR observations

OBJECTIVE

Pediatric oncology patients who undergo intensive chemotherapy develop anemia caused by myeloid suppression that necessitates transfusions that, in turn, cause iron deposition in the reticuloendothelial system. We describe MR imaging of iron overload in pediatric patients who underwent such chemotherapy and who have solid and hematologic tumors.

MATERIALS AND METHODS

The MR appearance of the liver, spleen, and bone marrow was evaluated in 13 children with both solid (n = 10) and hematologic (n = 3) malignant lesions using known criteria for the presence of iron deposition. Findings were correlated with transfusional history, chemotherapeutic regimens, and ferritin levels.

RESULTS

MR imaging obtained after chemotherapy and transfusional therapy revealed signs of iron deposition in the liver and spleen, particularly on T2-weighted images. Bone marrow signal intensity varied among patients. Pancreatic signal intensity was normal. Ferritin levels were elevated in all patients.

CONCLUSION

Reticuloendothelial system iron deposition present in follow-up MR imaging of pediatric solid and hematologic malignant lesions reflected the intensity of the chemotherapeutic regimen, the degree of myeloid suppression, and the resultant transfusional requirements. Such iron deposition appeared to have no effect on cardiac, liver, or pancreatic function.

Dideoxyinosine-induced pancreatitis in human immunodeficiency virus-infected children

Dideoxyinosine (ddI) is a widely used antiretroviral agent in treatment of HIV infection. Pancreatitis is a serious side effect. Two cases are reported, one with rapid development of a pseudocyst.

Chest radiographic data acquisition and quality assurance in multicenter studies

BACKGROUND

Multicenter studies rely on data derived from different institutions. Forms can be designed to standardize the reporting process allowing reliable comparison of data.

OBJECTIVE

The purpose of the report is to provide a standardized method, developed as a part of a multicenter study of vertically transmitted HIV, for assessing chest radiographic results.

MATERIALS AND METHODS

Eight hundred and five infants and children were studied at five centers; 3057 chest radiographs were scored. Data were entered using a forced-choice, graded response for 12 findings. Quality assurance measures and inter-rater agreement statistics are reported.

RESULTS

The form used for reporting chest radiographic results is presented. Inter-rater agreement was moderate to high for most findings, with the best correlation reported for the presence of bronchovascular markings and/or reticular densities addressed as a composite question (kappa = 0.71). The presence of nodular densities (kappa = 0.56) and parenchymal consolidation (kappa = 0.57) had moderate agreement. Agreement for lung volume was low.

CONCLUSION

The current tool, developed for use in the pediatric population, is applicable to any study involving the assessment of pediatric chest radiographs for a large population, whether at one or many centers.

Stage IVN neuroblastoma: MRI diagnosis of left supraclavicular "Virchow's" nodal spread

Stage IV neuroblastoma is associated with high mortality; an exception are patients whose stage IV status includes distant positive nodes, but no skeletal metastases-stage IVN neuroblastoma. We describe our experience with preoperative MRI in three patients with extensive abdominal neuroblastoma without cortical bony involvement but with unsuspected metastatic involvement to the left supraclavicular (Virchow's) node. We review findings of left supraclavicular nodal spread in five earlier cases of IVN neuroblastoma.

Intrasplenic masses of "preserved" functioning splenic tissue in sickle cell disease: correlation of imaging findings (CT, ultrasound, MRI, and nuclear scintigraphy)

PURPOSE

We studied six patients with sickle cell disease (SSD), five homozygous for sickle cell anemia and one with sickle beta-thalassemia, in whom rounded intrasplenic masses proved to be preserved functioning splenic tissue.

MATERIALS AND METHODS

Available images including computed tomography, ultrasonography, bone scans (Tc-99m MDP), liver spleen scans (Tc-99m sulfur colloid), and MRI were evaluated.

RESULTS

The masses were low density on CT (in an otherwise calcified spleen), hypoechoic relative to the echogenic spleen on US, and had the imaging characteristics of normal spleen on MRI. They failed to accumulate Tc-99m MDP but did demonstrate uptake of Tc-99m sulfur colloid.

CONCLUSION

In a patient with SSD and intrasplenic masses, proper correlation of multiple imaging modalities will establish the diagnosis of functioning splenic tissue and avoid mistaken diagnosis of splenic abscess or infarction.

Human immunodeficiency virus infection and multilocular thymic cysts

PURPOSE

Pathologic changes of the thymus, often seen in children with the human immunodeficiency virus (HIV), reflect direct invasion by the virus, followed by involution of the gland. A previously unknown form of thymic response to HIV infection, that of a multilocular thymic cyst, is reported.

MATERIALS AND METHODS

Findings were examined in three HIV-positive patients, two children and one adult first seen with large thymic masses.

RESULTS

All three had large, septate low-attenuation areas at computed tomography consistent with multilocular thymic cysts. The cystic nature of the lesions was confirmed with magnetic resonance imaging in two. Histopathologic examination, performed in two instances, helped establish the diagnosis. All patients remained in clinically stable condition. They all had parotid gland enlargement and lymphocytic interstitial pneumonia.

CONCLUSION

Multilocular thymic cysts are probably another manifestation of the diffuse infiltrative lymphocytosis syndrome, usually associated with a milder course of acquired immunodeficiency syndrome.

Pneumothorax as the presenting sign of Pneumocystis carinii infection in an HIV-positive child with prior lymphocytic interstitial pneumonitis

An HIV-positive child presented with a pneumothorax secondary to cavitary Pneumocystis carinii pneumonia (PCP). Lymphocytic interstitial pneumonitis had been evident on earlier radiographs but had resolved, concurrent with a decrease in her CD4 counts, before the radiographic changes of PCP became evident. As immune function declines in HIV-positive children, the chest radiograph may paradoxically clear. In such a setting, development of focal lung disease, including pneumothorax, may herald Pneumocystis carinii infection.

Benign adenomatous kidney neoplasms in children with polycythemia: imaging findings

PURPOSE

To correlate pathologic, computed tomographic (CT), and ultrasound (US) characteristics of nephrogenic adenofibromas and embryonal adenomas (uncommon pediatric renal tumors) in children.

MATERIALS AND METHODS

Medical records and imaging and pathologic findings were reviewed in three children (aged 6 1/2, 7, and 11 years) with adenomatous renal tumors and polycythemia. Specimens were reviewed at the National Wilms Tumor Study Pathology Center (Loma Linda, Calif).

RESULTS

All tumors were smaller than 3 cm in greatest dimension. They were hyperechoic on US scans and had high attenuation on unenhanced CT scans. Two patients underwent nephrectomy for initial diagnosis of Wilms tumor. The third underwent local excision. At pathologic examination, embryonal-appearing adenomatous epithelial cells were found to form tubules and papillae with abundant psammomatous calcifications. Two masses were classified as embryonal adenomas and one as nephrogenic adenofibroma.

CONCLUSION

Increased attenuation on CT scans and increased echogenicity on US scans of renal adenomatous tumors are distinctive findings that may reflect the presence of tubulopapillary structures and psammomatous calcifications.

Panner's disease: X-ray, MR imaging findings and review of the literature

Panner's disease, avascular necrosis of the capitellum, was first described on X-ray examination of the elbow. It represents a major threat to the elbow joint integrity, and it is important to diagnose early. Panner's disease occurs most commonly in young children who play baseball, and in competitive gymnasts. Although considered a rare entity, it probably is underdiagnosed. We present the X-ray and MR imaging findings in a young boy with Panner's disease. The MR imaging findings in Panner's disease have not been previously reported.

Congenitally short trachea and high carina with left mainstem bronchus compression by the ligamentum arteriosum

We report a patient with congenitally short trachea (CST), defined as a decreased number of tracheal rings and high carina, who had respiratory distress and overaeration of the left lung secondary to extrinsic narrowing of the distal mainstem bronchus by ligamentum arteriosum compression.

Deferoxamine-induced platyspondyly in hypertransfused thalassemic patients

Deferoxamine chelation therapy (widely used to reduce iron overload in hypertransfused thalassemic patients) has been implicated in causing skeletal growth abnormalities (rachitic-like changes in the long bones and vertebral body flattening), particularly when used in early infancy and at high dose levels. Radiographs of seven hypertransfused and well-chelated patients with thalassemia were reviewed. For two patients, serial films of the spine from the early 1970s to the present revealed a sequence of changes in the vertebral bodies, beginning with normal bodies that became bulbous and subsequently flattened. These two patients had begun deferoxamine chelation therapy early in infancy. The bone changes, though slightly reminiscent of post-radiation changes, are milder and result in a final Scheuermann-like picture.

Soft-tissue sarcomas: MR imaging findings after treatment in three pediatric patients

PURPOSE

To characterize the skeletal and bone marrow magnetic resonance (MR) imaging changes during and after treatment of childhood soft-tissue tumors.

MATERIALS AND METHODS

Three boys with soft-tissue sarcomas of the popliteal fossa underwent surgery, radiation therapy, and chemotherapy. Plain radiographic and MR imaging findings were correlated with the effect of treatment.

RESULTS

After radiation therapy, MR images revealed findings that resembled those of rickets at sites of irradiation in the three patients. These findings included metaphyseal sclerosis, metaphyseal fraying, and epiphyseal plate widening. Bone marrow imaging changes were temporally related to therapy. During chemotherapy, reconversion to hematopoietic marrow was noted in nonirradiated areas in two patients, but after cessation of all treatment, these areas converted back to fatty marrow. Irradiated areas of bone marrow remained fatty throughout therapy in the three patients.

CONCLUSION

Awareness of the MR imaging findings related to antineoplastic treatment of soft-tissue tumors is important to distinguish these changes from progression of primary disease.

MRI marrow observations in thalassemia: the effects of the primary disease, transfusional therapy, and chelation

The magnetic resonance bone marrow patterns in thalassemia were evaluated to determine changes produced by transfusion and chelation therapy. Thirteen patients had T1- and T2-weighted images of the spine, pelvis and femurs. Three received no therapy (age range 2.5-3 years). Three were hypertransfused (transfused to maintain a hemoglobin greater than 10 g/dl) and not chelated because of age (age range 6 months-8 years). Seven were hypertransfused and chelated (age range 12-35 years). Signal characteristics of marrow were compared with those of surrounding muscle and fat. Fatty marrow (isointense with subcutaneous fat) was compared with red marrow (hypointense to fat and slightly hyperintense to muscle). Marrow hypointense to muscle was identified as iron deposition within red marrow. The untreated group demonstrated signal consistent with red marrow throughout the central and peripheral skeleton. Hypertransfused but not chelated patients demonstrated marked iron deposition in the central and peripheral skeleton. Hypertransfused and chelated patients demonstrated iron deposition in the central skeleton and a mixed appearance of marrow in the peripheral skeleton. The MR appearance of marrow in thalassemia is a reflection of the patient s transfusion and chelation therapy. Iron deposition occurs despite chelation therapy in sites of active red marrow. As red marrow retreats centrally with age, so does the pattern of iron deposition. The long-term biological effects of this iron deposition are unknown.

Midgut malfixation in patients with congenital diaphragmatic hernia: what is the risk of midgut volvulus?

Twenty-four patients with repaired diaphragmatic hernia had upper gastrointestinal series to assess the rotation and fixation of the bowel. A spectrum of rotational abnormalities was present in almost all patients, although those with repaired right-sided hernias demonstrated a more obvious anomaly of rotation than those with repaired left-sided hernias. No patient developed a midgut volvulus despite the presence of malfixation. Postoperative adhesions likely limit the occurrence of volvulus.

Severe mid-cervical kyphosis with cord compression in Larsen's syndrome and diastrophic dysplasia: unrelated syndromes with similar radiologic findings and neurosurgical implications

Mid-cervical kyphosis in diastrophic dysplasia (DD) with cord compression and weakness has been recognized for the last three decades. A strikingly similar situation exists in Larsen's syndrome (LS), an otherwise unrelated problem of weakness with lay joints and dislocations with typical facies. Forty patients with DD were studied of whom seven had cervical spine kyphosis: one patient had spontaneous correction over the ensuing two decades. Seven patients with LS were studied of whom four had cervical spine changes with cord compression. There was one sudden death among the patients with LS and no cases of spontaneous correction. Muscle weakness in DD and LS should lead to evaluation of cervical spine kyphosis with cord compression. Plain films, CT and recently MRI are useful.

MR marrow signs of iron overload in transfusion-dependent patients with sickle cell disease

Magnetic resonance (MR) marrow signal in the axial and appendicular skeleton of 13 transfusion-dependent and chelated pediatric patients with sickle cell anemia (SSD) was compared with marrow signal in six non-transfusion-dependent patients with SSD. Hepatic, pancreatic, and renal MR signal were also evaluated. Indication for hypertransfusion therapy was primarily prior history of stroke. Transfusion-dependent patients had evidence of iron deposition throughout the imaged marrow and the liver, despite deferoxamine chelation therapy. Non-transfusion-dependent patients did not demonstrate grossly apparent signs of iron overload. Red marrow restoration was present in the spine, pelvis, and long bones and, in some patients, within the epiphyses. Marrow edema secondary to vaso-occlusive crises was evident in the metaphyses and diaphyses of long bones in areas of both red and fatty marrow and was best seen using fat-saturated T2-weighted imaging techniques.

Complex colon duplication mimicking an obstructed, non-functioning kidney in a newborn with imperforate anus and spinal dysraphism

Gastrointestinal (GI) duplications contain tissue resembling several portions of the GI tract and are associated with vertebral and genitourinary (GU) abnormalities [1-4]. We report a newborn with low, imperforate anus and lumbosacral dysraphism, who presented with a large cystic mass in the left renal fossa and pelvis. The flank mass (felt initially to be a dysplastic kidney and ureter) proved to be a complex GI duplication with histologic evidence of gastric, small bowel, and colonic mucosa, as well as respiratory epithelium and pancreatic tissue.

Testicular microlithiasis in a child with torsion of the appendix testis

We report on an 8-year-old boy with a unilateral testicular mass and bilateral diffusely echogenic testes on sonography. At inguinal exploration torsion of an appendix testis with a reactive phlegmon was found and testis biopsy revealed significant testicular microlithiasis. To our knowledge our case demonstrates a previously undescribed presentation of testicular microlithiasis. The literature is reviewed and this disease entity is discussed.

MR signal characteristics of cadaveric bone allografts in three children with primary bone tumors treated with limb salvage therapy

Three children with adult cadaveric bone allografts for the treatment of bone malignancies are presented. Follow-up magnetic resonance (MR) imaging demonstrated decreased signal on T1-weighted imaging and increased signal on T2-weighted imaging in the allograft without clinical evidence of recurrent disease. These signal characteristics appear to be a normal finding in cadaveric bone allografts and should not be mistaken for recurrence. The finding may reflect persistent marrow necrosis within the allograft marrow cavity.