Garre’s Osteomyelitis (Chronic Osteomyelitis with Proliferative Perosteitis)

• Chronic Non Suppurative Sclerosing Osteitis/ Periostitis Ossificans.
• Non suppurative productive disease characterized by a hard swelling.
• Occurs due to low grade infection and irritation
• The infectious agent localizes in or beneath the periosteal covering of the cortex & spreads only slightly into the interior of the bone.
• Occurs primarily in young persons who possess great osteogenic activity of the periosteum.

Clinical Features

• Uncommonly encountered, described in tibia and in the head and neck region, in the mandible.
• Typically involves the posterior mandible & is usually unilateral.
• Patients present with an asymptomatic bony, hard swelling with normal appearing overlying skin and mucosa.
• On occasion slight tenderness may be noted
• pain is most constant feature
• The increase in the mass of bone may be due to mild toxic stimulation of periosteal osteoblasts by attenuated infection.

Radiographic features

• Laminations vary from 1 – 12 in number, radiolucent separations often are present between new bone and original cortex. (“onion skin appearance”)
• Trabeculae parallel to laminations may also be present.

Histologic Features

• Reactive new bone.
• Parallel rows of highly cellular & reactive woven bone in which the individual trabeculae are oriented perpendicular to surface.
• Osteoblasts predominate in this area.

D/D for Garre’s Osteomyelitis

• Ewing's sarcoma
• Caffey’s disease
• Fibrous dysplasia
• Osteosarcoma

Treatment

• Removal of the offending cause.
• Once inflammation resolves, layers of the bone consolidate in 6 – 12 months, as the overlying muscle helps to remodel.
• If no focus of infection evident, biopsy recommended.