Physical examination was remarkable only for mild (4/5) muscle weakness in both legs and loss of deep tendon reflexes at the ankles.
A bone scintigram demonstrated a focal "cold" lesion at T-12 (arrow), corresponding to the radiographically evident destructive lesion. There were no other abnormalities.
Radiation therapy was started, but because of progressive worsening of leg weakness and development of incontinence, a decompressive laminectomy was performed from T-11 to L-1. Cord compression, due to tumor within the spinal canal, was evident at surgery. Pathologically, the tumor was felt to represent a chordoma.
Numerous reports of "cold" lesions on bone scintigraphy appear in the literature; most are caused by artifacts, loss of blood supply or loss of bone. Barium, jewelry, coins, pacemakers and orthopedic, breast or dental prostheses may cause artifacts which may not be easily recognized. Ischemic bone may be seen as a "cold" spot because perfusion is necessary for uptake of the radiopharmaceutical. Avascular necrosis, acute osteomyelitis, radiation therapy, frostbite, electrical burns, Gaucher's or sickle cell disease (with or without infarction), may cause sufficient ischemia to be reflected on a bone scan as a photopenic lesion. Bone loss is most commonly seen following surgical resection or arthroplasty; other entities include congenital anomalies such as absence of a pedicle, parietal thinning or midline sternal defect, benign conditions such as myelofibrosis, hemangiomas or brown tumors and malignancies, both primary and metastatic. Primary bone malignancies include multiple myeloma, osteolytic osteosarcoma and fibrosarcoma. A single case of a sacrococcygeal chordoma presented with a photopenic lesion has been reported. The most common metastatic lesions are from breast, lung and in children, neuroblastoma.
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J. Anthony Parker, MD PhD, email@example.com