The role of octreotide scintigraphy in rheumatoid arthritis and sarcoidosis.

Somatostatin receptors are widely expressed on cells and tissues throughout the human body. Apart from their expression in the physiological target organs of the peptide, somatostatin receptors are also expressed in various tumours. The expression of somatostatin receptors on neuroendocrine tumours led to the development of somatostatin receptor scintigraphy using [(111)In-DTPA-D-Phe(1)]-octreotide ((111)In-pentetreotide) in order to visualize somatostatin receptor positive tumours and their metastases in vivo. Previous studies reported the expression of somatostatin receptors in both normal and pathological cells and tissues of the human immune system as well. Somatostatin receptors have been demonstrated in Hodgkin's and non-Hodgkin's lymphomas and sst scintigraphy has shown to be a useful tool in diagnosis and staging of these diseases. Moreover, sst expression has also been detected in granulomateus diseases, like sarcoidosis and auto-immune diseases, like rheumatoid arthritis. In this paper we discuss the (possible) role of somatostatin receptor scintigraphy in diagnosis, staging or follow-up of patients suffering from sarcoidosis and rheumatoid arthritis.