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Related to overlap syndrome: Mixed connective tissue disease
overlap syndromeGI disease The presence of histologic features of Crohn's disease and ulcerative colitis in the same Bx, precluding a specific diagnosis of either; overlap occurs in ±15% of Bxs of these 2 conditions Neurology See Parkinsonism plus syndromes Rheumatology A connective tissue disease with features of 2 or more rheumatologic disorders–eg, lupus erythematosus-mixed connective tissue disease overlap, rheumatoid arthritis-lupus overlap–1% of cases, scleroderma-polymyositis overlap–8-12% of cases and lupus erythematosus-polymyositis overlap– 5-10% of cases Vascular disease A combination of systemic necrotizing vasculitis with features of polyarteritis nodosa and Churg-Strauss disease–allergic angiitis and granulomatosis, involving small and medium muscular arteries of the lung, causing HTN and hypersensitivity.
A rheumatological disorder with features suggestive of several kinds of connective tissue disease, but not definitively diagnostic of any single syndrome. Overlap syndromes typically have elements of systemic lupus erythematosus, rheumatoid arthritis, and progressive systemic sclerosis, among other illnesses.