Skeleton

RICKETS: Tissue from a young turkey (X40; inserts X400; Von Kossa stain). Description: Bone with an open growth plate. Diffused marked thickening of the physis. The zone of proliferation is demonstrated with thickened haphazard arranged chondrocyte hyperplasia (upper insert) and reduce of blood vessel penetration. Reduce mineralization of the cartilage matrix indicated by the negative Von Kossa staining, osteoclast hyperplasia (lower insert), and thickening of the osteoid seam in the metaphysis. The epiphysis is demonstrated with a long narrow fracture with hemorrhage accumulation. Morphologic Diagnosis: Physeal dysplasia with haphazard chondrocyte arrangement in the zone of proliferation – Rickets. Etiologic Diagnosis: VitaminD3/Calcium deficiency. Dr Z. Raviv

1.OSTEOCHNDROSIS / 2. OSTEOMYELITIS:Tissue from a broiler chicken (subgross; insert X40)
Description: Bone (proximal tibiotarsus). Sever disruption of the growth plate organization with abnormal endochondral ossification of metaphysial trabeculae. Epiphysis is demonstrated with necrosis and fibrin thrombi with rod shaped bacteria in blood vessels, and irregular proliferation of chondrocytes in clusters (chondrones). Multifocal to coalescing cartilage necrosis and appearance of eosinophilic streaks (insert), and clefts formation in the physis. Multifocal metaphyseal heterophil and macrophage infiltration with accumulation of eosinophilic cell debris (arrow) and intralesional bacterial microcolonies. 
Morphologic Diagnoses: 1. Severe multifocal epiphyseal vascular necrosis with septic fibrin thrombi, epiphyseal chondrones, and multifocal physeal cartilage necrosis with clefts formation and eosinophilic streaks – Osteochondrosis; 2. Multifocal heterophilic osteomyelitis with intralesional bacteria.

Tissue from a broiler chicken (sub-gross and X400)
Description: Bone with an open growth plate. The metaphysis is demonstrated with a large sheet of hyaline cartilage that is poorly penetrated by blood vessels, extensive chondrocyte necrosis, and matrix eosinophilia; the chondrocytes resemble those in the zone of hypertrophy with smaller lacunae and more abundant matrix
(asterisk). The cortical bone adjacent to the abnormal cartilage is thinner. The cartilage plug is underlined by irregular trabeculae (arrow).
Morphologic Diagnosis: Metaphyseal dysplasia with necrotic hyaline cartilage plug.
Disease Diagnosis: DYSCHONDROPLASIA. Dr Z. Raviv

Tissue from a young turkey (X40; inserts X200; Von Kossa stain).

Description: Bone with an open growth plate. Sever elongation of the zone of degenerating hypertrophy with normal vascular invasion, and poor mineralization of the primary and secondary spongiosas (indicated by the negative Von Kossa staining). The metaphysis (insert) is demonstrated with decrease number of osteoclasts, hypertrophy and hyperplasia of osteoblasts, and limited osteoid deposition.

Morphologic Diagnosis: Physeal dysplasia with hyperplasia of the zone of degenerating hypertrophy – Rickets

Etiologic Diagnosis: Phosphorous deficiency. Dr Z. Raviv