Grocott methenamine silver and periodic acid-Schiff positivity in cutaneous Mycobacterium avium complex infection.

Although often used to identify fungi within granulomatous infiltrates, Grocott's methenamine silver (GMS) and periodic acid-Schiff (PAS) stains have also been reported to stain Mycobacterium leprae (1). There is limited literature concerning the results of these stains when applied to other mycobacterial species. We have recently observed prominent GMS and PAS positivity in a case of cutaneous Mycobacterium avium complex (MAC) infection.