Practice

A70-year-old woman receivinglong-term corticosteroid therapyfor sarcoidosis presented with hip pain. She underwent whole-body technetium 99m methylene diphospho-nate bone scintigraphy to exclude avas-cular necrosis of the femoral head. Al-though there was no suggestion of avascular necrosis, multiple areas of in-creased activity were present in the axial and proximal appendicular skeleton (Figure 1). We were concerned that these findings suggested multiple skeletal metastases. A computed tomography scan of her chest showed bilateral pul-monary opacities and an infiltrating process involving the mediastinum and both hila (Figure 2). A computed to-mography scan of her abdomen identi-fied splenomegaly and lymphadenopa-thy. Our differential diagnosis included small-cell lung cancer, sarcoma, lymph-oma and infection. The patient had received a diagnosis of sarcoidosis 5 years earlier when she presented with lymphadenopathy and night sweats. The initial workup in-cluded a computed tomography scan that showed lymphadenopathy and an axillary lymph-node biopsy that revealed noncaseating granulomata (Appendix 1, available at www.cmaj.ca/cgi/content /full/178/2/153/DC1). The radiologist re-viewing the current computed tomogra-phy scan did not receive this background information and suspected a malignant process. The patient’s respirologist sub-sequently performed bone-marrow biop-sies, which demonstrated noncaseating granulomata consistent with skeletal sarcoidosis. The patient’s condition has been stable, and a repeat bone scan after 2 years of follow-up showed no change. Sarcoidosis is a granulomatous disease of unknown cause that affects various organ systems (Box 1).1 The disease is A case of skeletal sarcoidosis imitating skeletal metastases on bone scintigraph