Skeletal muscle metastases: a three-part study of a not-so-rare entity.

OBJECTIVE: Our purposes were to explore the epidemiology of metastases to skeletal muscle and their detection on fused positron emission tomography and computed tomography. MATERIALS AND METHODS: We evaluated the epidemiology of skeletal muscle metastases in the literature and among cases from our hospital and studied the prevalence and appearance of skeletal muscle metastases among 433 patients undergoing fused positron emission tomography and computed tomography for non-small-cell lung cancer. RESULTS: We found 264 cases of skeletal muscle metastases in 151 articles. Mean age was 57.8 years with 67% men. At our hospital we studied 70 cases. Mean patient age was 55.7 years with 63% men. The most common source was lung cancer, and the most common site of involvement was the muscles of the trunk. Among our lung cancer patients undergoing fused positron emission tomography and computed tomography, we found 7 (1.6%) with skeletal muscle metastases. In only one of these seven patients was the metastasis first discovered by another imaging modality. In one patient discovery of the metastasis at fused positron emission tomography and computed tomography changed management. CONCLUSION: Skeletal muscle metastases are not rare. They may be more apparent at fused positron emission tomography and computed tomography than at other staging examinations, particularly contrast-enhanced CT scanning. Radiologists need to be alert to their presence when interpreting staging examinations in cancer patients.

Tumor necrosis in osteosarcoma: inclusion of the point of greatest metabolic activity from F-18 FDG PET/CT in the histopathologic analysis.

OBJECTIVE: To determine if the location of the point of maximum standardized uptake value (SUVmax) being included in or not included in the histopathologic slab section corresponded to tumor necrosis or survival. MATERIALS AND METHODS: Twenty-nine osteosarcoma patients underwent post-chemotherapy [fluorine-18]-fluoro-2-deoxy-D: -glucose (FDG) positron-emission tomography-computed tomography (PET/CT) prior to resection. PET/CT images were correlated with slab-section location as determined by photographs or knowledge of specimen processing. The location of the point of SUVmax was then assigned as being 'in' or 'out' of the slab section. Cox's proportional hazard regression was used to evaluate relationships between the location and value of SUVmax and survival. Logistic regression was employed to evaluate tumor necrosis. RESULTS: No correlation was found between the SUVmax location and survival or tumor necrosis. High SUVmax correlated to poor survival. CONCLUSION: High SUVmax value correlated to poor survival. Minimal viable tumor (> 10%) following chemotherapy is a known indicator of poor survival. No correlation was found between the location of SUVmax and survival or tumor necrosis. Therefore, the SUVmax value either does not correspond to a sufficient number of tumor cells to influence tumor necrosis measurement or it was included in the out-of-slab samples that were directed to viable-appearing areas of the gross specimen. Since high SUVmax has been previously found to correspond to poor tumor necrosis, and tumor necrosis is simply an estimate of the amount of viable tumor, SUVmax likely represents many viable tumor cells. Therefore, when not in the slab section, SUVmax was likely included in the tumor necrosis measurement through directed sampling, validating our current method of osteosarcoma specimen analysis.

Use of the tyrosine kinase inhibitor sunitinib in a patient with von Hippel-Lindau disease: targeting angiogenic factors in pheochromocytoma and other von Hippel-Lindau disease-related tumors.

CONTEXT: von Hippel-Lindau disease is characterized by highly vascularized tumors of multiple organs. EVIDENCE ACQUISITION: We present a patient with von Hippel-Lindau disease with multiple renal and pancreatic tumors and a malignant pheochromocytoma infiltrative of the sacrum and associated with lymph nodule metastases. The pheochromocytoma expressed high protein level of vascular endothelial growth factor and platelet-derived growth factor-beta receptor. The patient presented with a poor performance status, severe pelvic pain, weight loss, and manifestations of catecholamine excess. EVIDENCE SYNTHESIS: Treatment against malignant pheochromocytoma with surgery, chemotherapy, or participation in clinical trials was not feasible because of the patient's poor performance status, the presence of multiple tumors, and the extension of the pheochromocytoma into the bones. Patient was treated with sunitinib, a potent tyrosine kinase inhibitor of vascular endothelial growth factor, platelet-derived growth factor, RET, c-KIT, and FLT-3 receptors. Six months of treatment with sunitinib was associated with normalization of the patient's performance status and blood pressure, absence of symptoms of catecholamine excess, weight gain, disappearance of pain, shrinkage of each of the tumors (50% in the largest renal tumor, 38% in the largest islet cell tumor, 21% in the pelvic malignant pheochromocytoma), and reduction of plasma normetanephrines and chromogranin A. CONCLUSION: This study provides evidence that targeting tyrosine kinase receptors such as the vascular endothelial growth factor pathway and the platelet-derived growth factor-beta receptor may have value in the treatment of VHL-related tumors including pheochromocytoma.