Subperiosteal lesions: a radiologic spectrum of pathologies and diagnostic considerations.

Subperiosteal lesions encompass traumatic, infectious, benign neoplastic, and malignant processes arising between the periosteum and the underlying cortex. Because the periosteum is more loosely adherent in children and young adults, several entities are encountered more often in paediatric populations. Accurate diagnosis requires integration of imaging characteristics such as lesion location, composition and cortical response, and relevant clinical context. This imaging-focused review discusses subperiosteal haematoma, abscess, ganglion, osteoid osteoma, osteoblastoma, aneurysmal bone cyst, lipoma, haemangioma, chondroid lesions, Ewing sarcoma, osteosarcoma and metastases. We lead with a practical imaging diagnostic algorithm and use the accompanying tables as the core summary, with the subsequent discussion emphasising the principal imaging discriminators and differential diagnoses. Tissue diagnosis is discussed where imaging is indeterminate or an aggressive surface tumour is suspected.