Rathke Cleft Cyst
Rathke cleft cysts are benign formations and not true tumors. Rather, they take the form of a fluid-filled pouch known as a cyst.
Rathke cleft cysts are thought to form during embryological development from a developmental precursor of the pituitary gland called the Rathke’s pouch. As development proceeds in the womb, the hollow center of the Rathke’s pouch shrinks to a narrow trough called a cleft. Normally, this cleft continues to regress and then disappears, forming the anterior, or front, part of the pituitary gland.
If the Rathke’s pouch does not close completely, a Rathke cleft cyst can form. The exterior of the cyst is a thin clear membrane while the interior is filled with fluid.
How common are Rathke cleft cysts?
Symptomatic Rathke cleft cysts account for fewer than one percent of all tumors that arise within the brain.
How are Rathke cleft cysts diagnosed?
Asymptomatic (not producing symptoms) Rathke cleft cysts are sometimes found on magnetic resonance images (MRI) or computed tomographic (CT) scans ordered for other conditions or injuries.
If your symptoms suggest a Rathke cleft cyst or other pituitary disorder, your doctor will order imaging studies, like MRI and CT, to determine the presence and location of the cyst. Blood tests may also be performed to determine what effects, if any, the cyst is having on the pituitary gland.
Typically, MRI is superior to CT for diagnosing a Rathke cleft cyst. However, CT can still be useful because it is better at detecting traces of calcium in various structures in the body. The presence of a calcified cyst near the pituitary gland can lead to a different diagnosis—most likely a craniopharyngioma.
Most Rathke cleft cysts do not produce any noticeable symptoms. In fact, it is common for them to go unnoticed until incidentally discovered on a magnetic resonance image (MRI) or computed tomographic (CT) performed for another reason.
When a Rathke cleft cyst does cause symptoms, the most common are as follows:
- Visual disturbances (about 47 percent of symptomatic cases)
- Diabetes insipidus (more common in women)
- Milky discharge from the breasts
If you are not experiencing any symptoms stemming from your Rathke cleft cyst, it may be best to simply watch the cyst over time and be vigilant for the onset of symptoms. It is possible for you to live your entire life and never experience symptoms from your intact Rathke cleft cyst.
Surgery is the best form of treatment. Radical or total resection of the cyst is seldom indicated because doing so can damage the pituitary gland. Rather, your surgeon will remove a small portion of the membrane surrounding the cyst and then drain its contents. The contents of the cyst are not infectious or toxic and will not harm your pituitary gland or the tissues around it.
Your surgeon will gain access to your pituitary region through the transsphenoidal approach—so named because the route crosses, or transects, your sphenoid bone. This bone is located behind your nose mostly within your skull.
Using precise surgical instruments, your surgeon will make an incision through your nasal cavity to create an opening in the sphenoid bone. Once your surgeon gains access to your sphenoid sinus, the air-filled area behind the sphenoid bone, further incisions will be made until a hole is created in the sella turcica—the bone that cradles and protects your pituitary gland.
Once your surgeon has your Rathke cleft cyst in the operative field, partial removal and draining of the cyst can proceed. Your surgeon will use high magnification to readily distinguish normal pituitary tissue from the Rathke cleft cyst.
After the entire cyst has been removed, the surgeon will clean the cavity and seal it. At Barrow Neurological Institute at Dignity Health St. Joseph’s Hospital and Medical Center, our surgeons specialize in two types of surgery for Rathke cleft cysts, microsurgery and endoscopic surgery:
- Microsurgery uses a powerful operating microscope to help your surgeon distinguish between tiny structures in and around the pituitary gland.
- Endoscopic surgery uses small tubes and a tiny camera to help your surgeon remove your tumor in small pieces.
Both aim to minimize trauma to the tissue surrounding your pituitary gland while facilitating a speedy recovery with as little pain or discomfort as is possible. Each technique possesses its own inherent advantages and disadvantages, and your surgeons will work with you to help determine which is the best fit for you.
Most patients are able to return home the day after their surgery for removing a Rathke cleft cyst, and nasal packing is seldom required.
Gamma Knife and other forms of radiosurgery are not indicated for the treatment of a Rathke cleft cyst.
- Date of last review: January 24, 2017
- Author: Andrew S. Little, MD