Multimodality evaluation of musculoskeletal sarcoidosis: Imaging findings and literature review.

Whilst the detailed X-ray features of thoracic manifestations of sarcoidosis are now clearly defined and known by most radiologists, the same does not apply to osteoarticular and muscular features of the disease, which may however raise major diagnostic problems, either because they are the presenting features of the disease (7% of cases) or because they develop during its course. The bony lesions of sarcoid dactylitis (classical Perthes-Jüngling disease) are very characteristic and well known. Many other presentations of bone and bone marrow sarcoidosis may however raise major diagnostic difficulties, particularly uni- or multifocal osteolytic and sclerotic forms of the disease. The articular manifestations of sarcoidosis are difficult to distinguish from those of the other inflammatory and degenerative arthropathies. The muscular lesions in sarcoidosis are generally clinically silent and therefore often missed. MRI has shown them to be very common in active sarcoidosis. Acute forms carry a good prognosis whereas chronic lesions are a presenting feature of multi-organ sarcoidosis. Finally, clinicians should always think about the possibility of an iatrogenic origin for musculoskeletal abnormalities seen in sarcoidosis, particularly those related to corticosteroid therapy.