Computed tomographic findings in canine leproid granuloma syndrome: a case series

Objective To describe the computed tomographic (CT) features of confirmed cutaneous and subcutaneous mycobacterial lesions in dogs. Animals CT images from three dogs with confirmed cutaneous and subcutaneous mycobacterial disease were retrospectively reviewed. Dogs presenting to a single hospital between September 2022 and February 2026 for chronic cutaneous and subcutaneous lesions were included if they underwent CT imaging of the lesion(s), surgical biopsy of an active lesion and Mycobacterium Polymerase Chain Reaction (PCR) testing on the tissue sample. Dogs were excluded if Mycobacterium PCR testing was negative. Clinical Presentation Dogs presented for chronic multifocal cutaneous and subcutaneous lesions which were unresponsive to initial antimicrobial therapies. Three dogs met the inclusion criteria: a 3.5‐year‐old female spayed Dogue de Bordeaux; a 5‐year 8‐month‐old female spayed whippet cross; and a 4‐year‐old English springer spaniel. Results All included cases had a positive mycobacterial PCR of a cutaneous or subcutaneous lesion for which a CT study was available at the time of tissue biopsy. All three cases displayed multifocal cutaneous and subcutaneous soft tissue nodules with peripheral rim enhancement. Two cases had visible cutaneous defects. Two cases had regional lymphadenomegaly. One case had multifocal pulmonary nodules presumed to be mycobacterial granulomas. In two cases, lesions clinically resolved within 5 months of appropriate antibiotic therapy. Clinical relevance Cutaneous mycobacterial infection appears similar to other diseases affecting the cutaneous or subcutaneous tissues and may be underdiagnosed due to limited awareness of the disease. CT may be a useful modality for assessing the extent of cutaneous or subcutaneous mycobacterial disease.