Fibrodysplasia ossificans progressiva in a Maine Coon cat with prominent ossification in dorsal muscle.

A one-year and six-month-old female Maine Coon cat presented with skin problems and paravertebral induration with a history of seven months. Survey radiographs and computed tomography revealed prominent calcifications in both sides of cervical, thoracic and lumbar vertebrae and soft tissue in femoral regions, below knee regions and in brachial regions. Histopathological findings from muscle biopsy samples showed connective tissue proliferation around adjacent skeletal muscle, cartilage formation and endochondral ossification. On the basis of these findings, this feline patient was diagnosed with fibrodysplasia ossificans progressiva (FOP). The most prominent signs observed in this FOP case were significant calcifications of dorsal muscle and presentation of cutaneous signs at the early stage.