Imaging features of alveolar soft-part sarcoma: a report from Children's Oncology Group Study ARST0332.

OBJECTIVE: There are few studies in the literature regarding the imaging features of alveolar soft-part sarcoma (ASPS). We performed a comprehensive assessment of the imaging characteristics of this rare tumor to determine whether there are features that suggest the diagnosis. MATERIALS AND METHODS: Twenty-two subjects with ASPS underwent pretherapy imaging as part of enrollment in Children's Oncology Group protocol ARST0332 for the treatment of nonrhabdomyosarcoma soft-tissue sarcomas: 16 patients underwent MRI; three, CT; and three, both MRI and CT. Two radiologists retrospectively reviewed the imaging studies by consensus and recorded tumor location, size, contour, internal architecture, signal characteristics, presence of flow voids, and enhancement patterns. RESULTS: The 12 females and 10 males in the study group ranged in age from 8 to 23 years 7 months (mean, 15 years 8 months). The most common anatomic site was the lower extremity (12/22, 55%) followed by the upper extremity (4/22, 18%). The maximal tumor diameter ranged from 2.3 to 20.0 cm (median, 5.9 cm). All tumors imaged with MRI had flow voids (19/19, 100%), and 19 (19/22, 86%) had large peripheral vessels, lobulated margins, and nodular internal architecture. Unenhanced T1-weighted MRI was available for 18 tumors: 14 (14/18, 78%) appeared slightly hyperintense to muscle. Of the 16 tumors imaged with contrast material, 11 (11/16, 69%) showed intense enhancement and five (5/16, 31%), moderate enhancement. Six tumors (6/16, 38%) had a thick enhancing peripheral rim with a nonenhancing center consistent with necrosis. CONCLUSION: The imaging features of ASPS include flow voids, large peripheral vessels, internal nodularity, and lobulated margins. Contrast administration produces intense to moderate enhancement, sometimes with a thick enhancing peripheral rim around central necrosis. Extremity tumors with these imaging features in a child or young adult should suggest the diagnosis of ASPS.

Radiographic findings in late-presenting congenital diaphragmatic hernia: helpful imaging findings.

BACKGROUND: Imaging findings in delayed presentation of congenital diaphragmatic hernia can be confusing and misleading, resulting in a delay in diagnosis. OBJECTIVE: To evaluate the often puzzling plain film findings of late-presenting CDH in an effort to determine whether any of the findings could be helpful in arriving at an early diagnosis. MATERIAL AND METHODS: We reviewed and documented the plain film findings and clinical data in eight patients seen during the last 20 years with late-presenting CDH. IRB exempt status was obtained in this study. RESULTS: There were five boys and three girls. The age range was 4 months to 12 years with a mean of 2.4 years. Five children presented with acute respiratory problems while three presented with acute abdominal pain. Two children presented with both respiratory and abdominal findings and one also presented with hematemesis. Two children had radiographic findings that were not difficult to analyze while the remaining six had findings that posed initial diagnostic problems. CONCLUSION: Although not common, late-presenting CDH can result in confusing plain film radiographic findings and a delay in diagnosis. We found that the most important finding in analyzing these radiographs is in evaluating the location and position of the gastric bubble with the more common left-side hernias.

Intradural extramedullary Ewing tumor of the lumbar spine.

A 38-year-old man presented with a highly symptomatic lumbar intradural extramedullary tumor. MRI features strongly suggested a myxopapillary ependymoma, with a possible drop metastasis. No filum terminale or spinal-cord attachment to the tumor was seen intraoperatively. Histopathology, surprisingly, indicated a malignant round-cell tumor, strongly CD 99-positive, and FISH indicated a rearranged ESWR1 locus. A diagnosis of Ewing tumor (ET) was made. Only eight cases in the lumbar region have been previously reported.