[Undifferentiated connective tissue disease : what is it ?].

The term undifferentiated connective tissue disease (UCTD) describe patients presenting with clinical and serological manifestations of systemic autoimmune diseases but not fulfilling the criteria for any defined connective tissue diseases. The challenge is to differentiate patient with a stable UCTD from patients that will evolve to a connective tissue disease with therapeutic and prognostic impact. This article describe UTCD concept, clinical presentation, evolution, and prognostic factors and patients management.