Mycobacterium resembling Mycobacterium fortuitum that produces brown pigment.

Two cultures of acid-fast bacilli with characteristics most closely resembling those of Mycobacterium fortuitum were recovered as casual isolates from sputa of a patient with an apparent brochogenic tumor. One of the cultures was consistenly cream colored to rosy buff. The other, however, changed from buff to rust to dark brown and had the gross appearance of a fungus culture.