Parosteal Osteosarcoma of the Orbit

A review of nasal, paranasal, and skull base tumors invading the orbit

Tumors that invade the orbit are uncommon. The majority are meningiomas arising from the sphenoid ridge (66%). Others are bone and cartilage tumors arising from the surrounding bones of the orbit, pituitary adenomas, and epithelial tumors arising from the paranasal sinuses and nasal cavity. Meningiomas occur more often in women, whereas epithelial tumors have a predilection for men. Meningiomas and epithelial tumors typically present in the sixth decade of life, whereas bone tumors tend to affect individuals in their third decade of life. Patients often present with a combination of ophthalmological and otorhinolaryngological symptoms, including proptosis, pain, decreased visual acuity, restrictions in motility of the eye, epistaxis, and nasal obstruction. Sarcomas and benign bone and cartilage tumors arise from surrounding structures, whereas carcinomas usually arise from the paranasal sinuses. Surgery is the mainstay of treatment. Depending on the aggressiveness and histology of the tumor, surgery may be combined with radiation and chemotherapy. The prognosis is generally poor, but varies depending on histology and cell origin, size of the tumor, and degree of invasion. Meningiomas and benign bone tumors have the best prognoses. Sinonasal undifferentiated carcinomas, small-cell neuroendocrine carcinomas, osteosarcomas, and rhabdomyosarcomas have poorer prognoses.