When and how to perform biopsies in a patient with a (suspected) connective tissue disease

In the differential diagnostic process for rheumatic inflammatory and/or connective tissue diseases (CTDs), history taking and physical examination are of main importance, more than additional investigations, as many diagnoses are clinical diagnoses with specific clinical/patterns and gold standards are often lacking. In rheumatic diseases and, especially, CTD, many organ systems apart from the joints may be involved. These include the skin and underlying tissues, muscles, salivary glands, nerves, kidneys and blood vessels. Biopsy specimens of these tissues may be helpful in establishing a diagnosis, in assessing the extent and severity of organ involvement and sometimes in monitoring therapy. In this chapter, practical information is described regarding which clinical practice might indicate a need for biopsy, and on how to prepare the patient, how to perform the biopsy and handle the biopsy specimen. In addition, the limitations and complications one should be cautious of are described. For full details of the clinical spectrum of the diseases and the histopathology, the reader is kindly referred to relevant textbooks.