Malignant Orbital Tumors

Excerpt

The orbits are paired structures separated by the nasal cavity and ethmoidal sinuses, which protect and house the globe and contain extraocular muscles, nerves, blood vessels, lacrimal apparatus, and adipose tissues. The walls of each orbit are formed by parts of 7 bones: frontal, sphenoid, maxillary, zygomatic, palatine, ethmoid, and lacrimal. Tumors arising in orbit can be classified according to their cell of origin as either primary, secondary, or metastatic.

Primary orbital tumors arise from structures within the confines of the bony orbit, including vascular, neural, mesenchymal, and osseous, and those arising from the lacrimal gland. Secondary orbital tumors are lesions that, by contiguity, extend to involve the orbit from neighboring structures such as the paranasal sinus, conjunctiva, eye (globe), eyelid, lacrimal sac, anterior and middle cranial fossae, other facial bone, skull, nasopharynx, palate, and parotid gland. The orbit can also rarely be the site for metastasis for some distant tumors.