"Ask the Expert” features answers by our experts to your clinical questions. Question: A 16-year-old girl with neurofibromatosis 1 (NF1) developed a mass in the thoracic wall between the 8th and 9th ribs. There was not a high clinical index of suspicion for malignancy pre-operatively, so there was no antecedent biopsy and the patient proceeded directly to attempted resection. Pathology showed an incompletely resected malignant peripheral nerve sheath tumor (<5 cm). PET scan performed 20 days post-operatively...