We report cutaneous mycobacterial infections in a cat and a dog with unexpected mycobacteria identified by PCR on formalin-fixed paraffin-embedded (FFPE) skin biopsy tissues. A 2-year-old indoor domestic cat from Pennsylvania, USA had subcutaneous nodules in the axillae, hindlimbs, and along the ventrum. Biopsy showed nodular histiocytic infiltrates with abundant intracellular acid-fast bacilli and mycobacterial immunolabeling, compatible with feline lepromatous leprosy.