Malignant neoplasm of orbit

This code signifies the presence of a cancerous tumor originating within the orbital cavity, the bony socket surrounding the eye. This malignancy can affect any of the tissues within the orbit, such as fat, muscle, nerves, or connective tissue, but excludes the eyeball itself.

Apply this code when documentation confirms a primary malignant neoplasm confined to the orbital structures. This is appropriate for diagnoses like rhabdomyosarcoma of the orbit, orbital lymphoma (primary), or other primary sarcomas or carcinomas arising within the orbit. Supporting documentation should include pathology reports confirming malignancy and imaging studies detailing the tumor's location within the orbit.

• Differentiate from malignant neoplasms of the eyeball (e.g., retinoblastoma, melanoma of choroid), which are coded elsewhere.
• Ensure the documentation specifies "primary" if applicable; metastatic orbital tumors are coded differently.
• Consider an additional code for the specific histological type of neoplasm if known and documented.