Skeleton

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

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

Proximal Tibiotarsus
Physis & Growth Plate: Severe disruption, abnormal ossification, cartilage necrosis, clefts, and chondrones. Epiphysis: Necrosis and septic fibrin thrombi (rod-shaped bacteria). Metaphysis: Heterophilic/macrophage osteomyelitis with necrotic debris and bacterial microcolonies.
Morphologic Diagnoses:  Osteochondrosis: Epiphyseal vascular necrosis, septic thrombi, chondrones, and physeal cartilage necrosis/clefts.
Osteomyelitis: Multifocal heterophilic osteomyelitis with intralesional bacteria.

Findings (Young Turkey, Von Kossa stain)
Physis & Growth Plate: Diffuse, marked thickening. Zone of proliferation shows haphazard chondrocyte hyperplasia and reduced vascular penetration. Matrix & Metaphysis: Reduced mineralization (negative Von Kossa), osteoclast hyperplasia, and thickened osteoid seams. Epiphysis: Narrow fracture with hemorrhage.
Diagnoses (Dr. Z. Raviv) - Morphologic Diagnosis: Rickets (Physeal dysplasia with haphazard chondrocyte arrangement in the zone of proliferation). Etiologic Diagnosis: Vitamin D3 / Calcium deficiency.