Miscellaneous conditions presenting to the rheumatologist

Musculoskeletal symptoms can occur in a variety of diseases, or as drug side effects. Presentations and conditions discussed in this section include: multisystem diseases (e.g. adult-onset Still’s disease, acute sarcoid arthritis, and amyloidosis); paraneoplastic syndromes (e.g. hypertrophic pulmonary osteoarthropathy, remitting seronegative symmetrical synovitis with pitting oedema, and tumour-induced osteomalacia); skin manifestations of rheumatic disease (e.g. panniculitis, neutrophilic dermatoses, and multicentric reticulohistiocytosis); primary joint pathology and synovial disorders (e.g. pigmented vilonodular synovitis, synovial osteochondromatosis, Charcot joint); rheumatic manifestations of haematological disease (e.g. haemophilia, sickle cell disease, leukaemia, lymphoma, and polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin abnormalities); rheumatic manifestations of metabolic disease (e.g. hereditary haemochromatosis, Wilson’s disease); disorders of the spine and axial skeleton (e.g. Tietze’s syndrome, diffuse idiopathic skeletal hyperostosis, and alkaptonuria); drug-induced rheumatic syndromes (e.g. statin-induced myopathy, drug-induced tendinopathy, drug-induced lupus, and allopurinol hypersensitivity).

T2-weighted Hypointense Tumors and Tumor-like Lesions

Most musculoskeletal tumors are hyperintense on T2-weighted images. However, some T2-weighted hypointense tumors and tumor-like lesions are encountered in everyday clinical practice. We explore the spectrum of such T2 hypointense tumors and tumor mimickers that can arise from (1) the bones, presenting as diffuse processes or focal lesions; (2) the joints including diffuse or focal synovial disorders, loose bodies, or substance depositions; and (3) soft tissues, comprising T2 hypointense tumors and tumor mimickers (those that contain abundant fibrous tissue, mineralization, or hemosiderin deposits). Appropriate magnetic resonance imaging sequence selection is required to identify and characterize these lesions confidently when imaging musculoskeletal tumors.