Nuclear scintigraphy findings for Askin tumor with In111-pentetreotide, Tc99m-MIBI and F18-FDG

摘要

Askin tumor is a rare disease which had previously been reported as being thallium-201 and gallium-67 avid. Varying data regarding 18F- fluorodeoxyglucose metabolism has been described with Ewing family of soft tissue tumors. In this case, we present a patient found to have an Askin tumor of the left chest wall which demonstrated indium-111 pentetreotide and technetium-99m MIBI avidity. The lesion did not show 18F- fluorodeoxyglucose hypermetabolism in this case despite the aggressiveness of the tumor. The patient was treated with surgical excision of the tumor and chemotherapy. Subsequently, contrast enhanced CT, indium-111 pentetreotide and technetium 99m-MIBI showed that the lesion had regressed. These findings suggest that Askin tumor can demonstrate Indium-111 pentetreotide and technetium 99m-MIBI uptake and need not be hypermetabolic on 18F-fluorodeoxyglucose exam. Keywords: Askin, Primitive neuroectodermal tumor, PNET, Ewing, FDG, MIBI, Pentetreotide, Chest wall mass, Pediatric radiologyCASE REPORTIn this case, a 17 year old girl with a past medical history of scoliosis, cerebral palsy and developmental delay presented with shortness of breath. A subsequent chest radiograph (figure 1) and contrast enhanced chest CT (figure 2A and ?and3A)3A) showed she had a large intrathoracic mass which was heterogeneously enhancing and arising from the chest wall. No calcifications were identified in the mass on CT. The mass was biopsied during the admission and histology demonstrated small round blue cells consistent with Primitive neuroectodermal tumor (PNET) of the chest wall (figure 4). Additionally, immunohistochemical staining was positive for CD-99 (figure 4B). An F18-FDG PET study using coincidence imaging with gamma camera was then performed to further characterize the lesion which showed the lesion not to be hypermetabolic (figure 3B). An In111-pentetrotide (figure 2B) and Tc99m-MIBI (figure 5A & B ) exam was also performed and the lesion demonstrated avidity for both radiopharmaceuticals. After en bloc resection of the tumor and chemotherapy, a repeat contrast enhanced chest CT (figure 6A), In111-pentetreotide (figure 6B) and Tc99m-MIBI (figure 7 A & B) scan was performed about 4 months later and demonstrated resolution of disease. Open in a separate windowFigure 1 A 17-year-old girl with Askin tumor of the left chest wall. Chest radiograph performed during admission for a chief complaint of shortness of breath. A large mass (*) arises from the left lower chest wall and abuts the left heart border.