Bone scintigraphy in osseous sarcoidosis
A 52-year-old man with back pain and right hip pain was referred to our hospital. He had a history of lung sarcoidosis for 21 years. The patient was treated with corticosteroids. As his disease was considered inactive, corticosteroids were discontinued approximately 2 years after diagnosis. Physical examination was normal. Neither lymphadenopathy nor skin lesions were detected. Laboratory tests were normal except alkaline phosphatase which was elevated (448 U/L, normal 40-150 U/L).\nPelvic radiographs showed sclerosis and radiolucency on multiple areas mimicking bone metastases [].\nA computed tomography (CT) of thorax showed sclerotic and lytic lesions on 1st and 10th thoracic vertebras in addition to the findings of stage 4 sarcoidosis in both lungs [].\nFurthermore, cranial CT and radiographs were obtained to investigate the involvement of cranium. Although radiographs were normal, CT of the cranium revealed lytic lesions in addition to extensive sclerosis []. There was no involvement of the brain parenchyma.\nThe patient was referred for bone scintigraphy to scan the whole skeleton. Bone scintigraphy was performed 3 h after intravenous injection of 20 mCi (740 MBq) Tc99m methylene diphosphonate. Bone scan demonstrated multiple areas of increased tracer accumulation at the calvarium, upper-to-lower thoracic spine, pelvic bones, sacrum, both sacroiliac joints, and both proximal femurs []. After scintigraphy, bone marrow biopsy was done at 10th thoracic vertebra and demonstrated non-caseating granulomata consistent with skeletal sarcoidosis.