Question: My surgeon diagnosed the patient with a benign tumor of the pineal gland. Which ICD-10 code should I report? Oregon Subscriber Answer: You should report D35.4 (Benign neoplasm of pineal gland) for a benign tumor of the pineal gland. Pineal gland defined: The pineal gland is a structure in the brain that produces a hormone called melatonin which plays an important role in controlling sleep. Tumors in the pineal gland may grow to compress the surrounding structures. Depending upon the structures that the tumorous mass compresses, the patient may experience headaches, vomiting, visual disturbances, balance and coordination problems, and/or hormonal imbalances.