Combined metabolic bone diseases, medullary aplasia and bacterial pneumonia in broad-snouted caiman (Caiman latirostris)

Seven juvenile broad-snouted caiman (Caiman latirostris), bred in captivity and subjected to a diet deficient in minerals and vitamins during the first months of life, developed intense cachexia and generalized loss of bone stiffness. In a histopathological evaluation, the proliferation of stellate elongated cells with scarce and eosinophilic cytoplasm in the middle of a loose fibrillar and eosinophilic extracellular matrix was observed, especially in the long bones, which was compatible with fibrous osteodystrophy. Diffuse disorganization of the chondrocyte columns of the endochondral ossification zones with a light multifocal presence of dilated blood capillaries characterized rickets. The bone marrow of the animals revealed intense replacement of active myeloid tissue with adipose tissue and rare promyelocytes, which were compatible with marrow aplasia. Additionally, caseous lesions were evident in the lungs of three animals and the histopathological findings and microbiological analysis were compatible with a bacterial pneumonia. The present work gives a detailed anatomopathological description of the case.