Minimally invasive minor salivary gland biopsy for the diagnosis of amyloidosis in a rheumatology clinic.

Background. Systemic amyloidosis is a potentially fatal condition, unless diagnosed and treated before development of irreversible organ damage. Demonstration of amyloid deposits within tissue biopsies is only definitive diagnostic method, which makes appropriate selection of biopsy site essential. Herein, we evaluated efficacy of minimally invasive minor salivary gland biopsy (MSGB) for the diagnosis of amyloidosis. Methods. We analyzed 37 biopsies taken from 35 patients. Suggestive findings for amyloidosis were significant proteinuria, renal impairment, refractory diarrhea, neuropathy, and restrictive cardiomyopathy. Minor salivary gland was the initial biopsy site in all subjects. When MSGB was negative but there was a high suspicion for amyloidosis, a kidney, duodenum, or rectal biopsy was performed for further investigation. Results. Mean age of patients was 45.4 and 21 were female. In 11 patients amyloidosis was diagnosed with MSGB. In overall 18 patients were diagnosed with amyloidosis. Sixteen of them were identified as being of AA type and two were AL type amyloidosis. The sensitivity of minimally invasive MSGB is 61.1% for diagnosing amyloidosis in this study. Conclusion. MSGB is a safe and simple method for the diagnosis of amyloidosis which can be performed in an outpatient setting. We suggest extensive use of this minimally invasive method.