Background: Garré type periostitis ossificans is a rare disease observed in children and young adults. It is a chronic, infective pathologic change of bone tissue, with a mild course, affecting portions of long bone shafts and causing their sclerotization and thickening. Small granulation or cicatrization foci are present in the marrow cavity, without purulence and bone defects. The predominant clinical symptom is dull pain, usually nocturnal.
Generalized symptoms or signs of local inflammation are rare.
Case report: A course of Garré type periostitis ossificans located in the tibia of an 11-year-old boy is described. Laboratory tests and USG of the lesion site did not reveal any abnormalities. X-ray and CT images showed
a spindle-shaped thickening of the tibial shaft, especially in the cortical layer, and narrowing of the marrow cavity, without periosteal reaction or soft tissue lesions. Scintigraphy of the skeletal system revealed enhanced radioligand
uptake by the affected site. Differential diagnostics excluded osteogenic sarcoma, Ewing sarcoma, benign osteoma, cartilaginous tissue tumors, Langerhans cell histiocytosis and fibrous dysplasia. After antibiotic
treatment, the clinical symptoms subsided. However, no evolution of radiological changes was observed. The boy has remained asymptomatic during 3-year follow-up.
Conclusions: Garré type periostitis ossificans should be taken into consideration in the differential diagnosis of bone diseases in children. The diagnosis is established on the basis of clinical and radiological presentation.
Long-term antibiotic therapy may bring beneficial clinical effects. However, radiological changes of the affected bone may persist for a long time.

Keywords: Garré type periostitis ossificans, bone tumor