Imaging Off Therapy/Surveillance
MRI of the brain and orbits without and with contrast is recommended during off therapy surveillance of an ocular, optic nerve sheath complex or orbital tumor. (GRADE C, SOR 1.00, very strong recommendation) CT is not a recommended modality for off therapy surveillance. Contrast-enhanced CT may be performed if MRI is contraindicated.
IMAGING RECOMMENDATION FOR CALVARIAL TUMORS
Calvarial neoplasms are rare among pediatric head and neck mass lesions. Primary pediatric calvarial lesions are often benign with dermoid and epidermoid cysts being the most common16. Very rare benign neoplasms of the calvarium include osteoma, osteoid osteoma, aneurysmal bone cyst, and osteoblastoma. Malignant calvarial tumors are mostly skeletal metastases, of which neuroblastoma is the most common17. Ewing sarcoma may also metastasize to the skull; primary calvarial Ewing sarcoma is rare. Multifocal or unifocal disease in LCH is also a common diagnosis, accounting for up to 12% of calvarial mass lesions in pediatric patients 18. Intraosseous meningiomas are exceedingly rare in children.
Calvarial mass lesions may present as a palpable mass, localized pain and swelling or be identified incidentally after identification at another site. For initial evaluation, imaging plays a role in lesion detection and determining the location and origin of lesion, whether it arises from the bone, soft tissue or extending from intracranially. Moreover, the imaging appearance can help characterize lesions, differentiating neoplastic versus non-neoplastic entities and benign versus malignant tumors. An additional goal of imaging is to provide detail regarding the extent of pathology and to determine the relationship between the lesion and the nearby structures such as brain and dura.