Neoplasm mimics of rheumatologic presentations: sialadenitis, ocular masquerade syndromes, retroperitoneal fibrosis, and regional pain syndromes.

IgG4-RSD should be suspected in any patient presenting with lacrimal or salivary gland enlargement, particularly if male and manifesting mild glandular dysfunction. A serum IgG4 level, if increased, may be helpful, although a gland biopsy staining for IgG4-positive plasma cells is the definitive test. Primary low-grade B cell lymphomas of the glandular tissue, specifically MALT lymphoma and other glandular malignancy, should be considered, particularly in patients with asymmetric glandular enlargement. Patients with idiopathic uveitis should have a thorough evaluation to exclude malignancy, in particular PIOL and melanoma in adults, and diffuse retinoblastoma and ALL in children. RF remains a diagnostic challenge and atypical features such as outward displacement of the retroperitoneal structures should raise the suspicion for a malignant infiltrative process. CRPS rarely may be the first presentation of an occult malignancy and requires a thorough review of age-appropriate cancer screening. Carpal tunnel syndrome, if bilateral or associated with other systemic features, should prompt a search for amyloidosis.