Abstract:

 ABSTRACT Objective: To evaluate the skin fat biopsy and rectal mucosal biopsy in the diagnosis of AL amyloidosis. Methodology: One hundred eighty six patients diagnosed as AL amyloidosis from January 2009 to October 2014 were included in this retrospective study. Using renal biopsy as the gold standard for diagnosis of AL amyloidosis, the diagnostic sensitivity between skin fat biopsy and rectal mucosal biopsy was compared. Results: There were 132 males and 54 females with an average age of 54.8±9.1 years old. Monoclonal immunoglobulin light chain was detectable in 143 patients (76.9%). The sensitivity of skin fat biopsy and rectal mucosal biopsy was 92.5% [95% confidence interval (CI), 0.88-0.97] and 94.9% (95% CI, 0.92-0.98), respectively. The positive rate of diagnosis increased to 100% by the combination of the two biopsy methods. Conclusion: Tissue biopsy continues to be the gold standard for diagnosis of AL amyloidosis. Skin fat and rectal mucosal biopsies, being simple procedures with low cost and compliment, have acceptable sensitivities. Combination of both methods can improve the positive rate. Therefore, they are preferred biopsy site for patients unsuitable of renal biopsy.

Key words: AL amyloidosis, skin fat biopsy, rectal mucosal biopsy, renal biopsy