LABIAL SALIVARY-GLAND BIOPSY IS A RELIABLE TEST FOR THE DIAGNOSIS OF PRIMARY AND SECONDARY AMYLOIDOSIS - A PROSPECTIVE CLINICAL AND IMMUNOHISTOLOGIC STUDY IN 59 PATIENTS

Objective. Reports of the detection of amyloidosis by labial salivary gland (LSG) biopsy have been mostly anecdotal. The aim of this study was to assess the value of this method in the diagnosis of amyloidosis. Methods. LSG biopsy tissues were studied with a combination method using Congo red stain and immunohistologic characterization using an antibody directed against the serum amyloid P (SAP) component. Electron microscopy was performed in all cases. In a prospective study, we evaluated 30 patients with biopsy-proven AA or AL amyloidosis. We compared these patients with a control group of 29 age-matched patients without clinical or biologic evidence of amyloid disease (14 had rheumatoid arthritis and 15 had plasma cell dyscrasia). Results. In 26 of the 30 patients with known systemic amyloidosis, amyloid deposits were identified on LSG biopsy (sensitivity of 86%). In 1 of the remaining patients, amyloid deposits were identified on LSG biopsy and systemic amyloidosis was confirmed by abdominal fat biopsy and I-123-labeled SAP scintigraphy. Conclusion. This study emphasizes the high sensitivity of LSG biopsy in the diagnosis of amyloidosis, even in the absence of oral symptoms.