Pineal Cysts: Worth a Second Look

Infographic for the Pineal Cysts Worth a Second Look Progressnotes Article
Illustration by Emma Vought

MUSC Health neurosurgeon identifies a novel constellation of symptoms that resolve upon excision of pineal cysts or cytomas

By Kimberly McGhee

The pineal gland, a fingertip-sized structure located deep in the center of the brain, is found in almost all vertebrates, and yet its function, if any, remains a mystery. Philosophers and mystics have sometimes magnified its importance, while physicians have tended to underestimate it. Seventeenth-century philosopher René Descartes thought it to be the seat of the soul, while nineteenth-century mystic Madame Blavatsky believed it to be an atrophied third eye. In contrast, medical science has long dismissed it as unimportant — a vestigial gland of little significance, the neurological counterpart of the appendix. For generations, neurosurgeons have been taught to discount imaging evidence of a pineal cyst as inconsequential, in part because resection of the gland in cases of pineal tumor has led to no functional loss.

This has left little clinical recourse to patients with pineal cysts who are experiencing symptoms such as headaches, double vision or nausea for which there is no other neurological explanation. Some patients are referred for psychiatric evaluation with the suspicion that the symptoms are psychosomatic. Others are left to seek relief for their symptoms one by one by seeing a variety of specialists.

Like most other neurosurgeons, Sunil J. Patel, M.D., chair of the Department of Neurosurgery, had been taught to dismiss pineal cysts as clinically inconsequential. Then, five years ago, a patient’s story and a resident’s question led him to re-examine that assumption. A patient presented with imaging evidence of a pineal cyst and a set of neurological symptoms that caused her to leave a very successful career and become virtually house-bound, unable to care for her children. Her symptoms were not consistent with a pineal tumor, and no other neurologic or metabolic cause for them could be found.

Having rounded on the patient, Patel was ready to hand down to a new generation of providers the long-held assumption that pineal cysts are clinically insignificant, when a resident raised the question whether it wasn’t possible, in the absence of all other explanations, that the pineal cyst was causing the patient’s problems. “It takes a young mind to question you,” said Patel. “It was a young resident who asked ‘Why not try removing the cyst/gland? How do you know that’s not causing her symptoms?’”

For the first time, after discussion with the patient, Patel opted to excise the cyst. The results shocked him. When the patient came in for a follow-up visit several weeks later, her symptoms had vanished. What’s more, the pathology report revealed that the excised mass was not a cyst at all but rather a benign tumor known as a pineocytoma.

Patel has since identified a constellation of symptoms — headaches, insomnia, episodic cognitive deficits such as speech or vision difficulties or lapses in short-term memory, and, rarely, numbness in limbs and problems with balance — that are associated with pineocytomas and that resolve upon their excision. He has also come to recognize certain changes on MRI that are indicative of pineocytomas. He highly suspects a pineocytoma when both characteristic symptoms and MRI changes are present. If the symptoms are interfering with a patient’s quality of life and all other causes have been ruled out, Patel recommends surgery to remove the suspected pineal lesion.

Patel, who is one of only a handful of surgeons in the world who resects pineal cysts, has now performed more than 40 of these surgeries. In most cases, the pineal cyst has turned out to be, as expected, a pineocytoma. Ninety percent of these patients have achieved complete symptom resolution, and all achieve at least partial resolution. In patients with comorbid conditions, such as migraine, the symptoms associated with the pineocytoma resolve, but those that are migraine-specific, for example, do not.

“The majority of the symptomatic pineal cysts have turned out to be benign tumors, and removing them does provide relief of symptoms.”

— Sunil J. Patel, M.D.

What does all of this mean for physicians? First, it’s worth taking a second look at MRI findings of a pineal cyst, because it could in fact be a pineocytoma. Even patients with small cysts who are not experiencing symptoms should undergo monitoring with MRI every year or so in case it turns out to be a cytoma and starts to grow. Second, patients already experiencing some of the telltale symptoms of the syndrome should be referred to a neurosurgeon with experience in intracranial masses for evaluation, because surgery could provide them complete or partial relief.

“Not all pineal gland cysts are asymptomatic and not all of them are nonneoplastic,” said Patel. “The majority of the symptomatic pineal cysts have turned out to be benign tumors, and removing them does provide relief of symptoms.”