A 15-year-old girl had severe Raynaud's phenomenon and arthralgias. A high ANA-IF titer was found and undifferentiated connective tissue disease was diagnosed. After 7 years of moderately flaring disease the patient deteriorated and presented with congestive heart failure, pleuropericardial effusion, hemolytic uremic syndrome, proteinuria and moderate hypertension. Autoantibodies against DNA, Sm-protein, and very high titers against U1RNP were detected. Therapy with high steroid doses, a cyclophosphamide pulse and 4 weeks of plasmaphresis with plasma exchange improved the heart, but not the renal condition. Symptomatic pancreatitis became the dominant problem of a progressively consuming process that resulted in the death of the patient. Post-mortem examination revealed widespread vasculopathy with intima proliferation and only minimal fibrosis involving the kidneys, heart and other main organs, including the pancreas. Taken together, the clinical picture was of an overlap between scleroderma and systemic lupus erythemathosus; the serologic and histopathologic findings suggest a diagnosis of a severe form of mixed connective tissue disease (MCTD).