KidsMD Health Topics

Arachnoid Cysts

  • Arachnoid cysts are fluid-filled collections between the brain or spinal cord and the arachnoid member, one of three membranes covering the brain and spinal cord.

    • The cysts contain normal spinal fluid that likely accumulates in early development before birth
    • Arachnoid cysts are very common
    • Most form on the brain; spinal cord cysts are much more rare
    • Males are four times more likely to have arachnoid cysts than females
    • Most do not need treatment and have no effect on brain development

    How Children’s approaches arachnoid cysts

    Boston Children's Hospital has exceptional plastic and neurosurgeons who can help assess whether or not your child's arachnoid cysts need treatment.  Children's Department of Plastic Surgery is one of the largest of its kind in the country and specializes in minimally invasive surgery. Their goal is for your child to have a speedy recovery with little to no scaring or long-term side effects.

  • What causes arachnoid cysts?

    Doctors still don't know what exactly causes arachnoid cysts, but they believe the cysts result from developmental abnormalities in the brain and spinal cord during early gestation. 

    What are the symptoms of an arachnoid cyst?

    The location and size of the arachnoid cyst will determine the degree and onset of symptoms.  Some children with the condition will never have symptoms. For those who do, typical symptoms include the following:

    • headache
    • nausea and vomiting
    • seizures
    • hearing and visual disturbances
    • vertigo
    • difficulties with balance and walking
  • Arachnoid cysts will likely be diagnosed with a detailed neurological exam and diagnostic tests, which may include the following:

    • magnetic resonance imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
    • computerized tomography scan (Also called a CT or CAT scan.) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
  • In general, most children with arachnoid cysts don't require any treatment.  On the rare occasions when the cysts are large enough to put excessive pressure on the surrounding brain, surgical treatment may be necessary to remove the cysts.

    Neurosurgeons at Boston Children's Hospital have been leaders in pursuing minimally invasive surgery, an approach that is far less traumatic than traditional surgery.  Using smaller and more precise instruments, means smaller incisions, quicker recovery, and fewer side effects. 

    Overall, the goal of treating arachnoid cysts is to decompress the cyst to relieve pressure on the brain. This can be done surgically by opening holes in the "bubble" of the cyst (fenestration) and letting it drain into the normal pathways that reabsorb spinal fluid. Depending on the size and location of the cyst, different techniques may be used, including:

    • a craniotomy - removing and replacing a small piece of the skull to get to the cyst
    • an endoscope - a small device that can be inserted within the cyst from a "minimally invasive" incision
    • shunt - inserting a tube into the cyst to drain them into another part of the body, such as the abdomen
  • Dumanel LuxamaSporting a cheeky grin, Dumanel Luxama shrieks and slaps the couch in the Brockton house that he and his father, Almane, have called home for the past three months. Tugging on the curtains, the 13-month-old baby from Haiti lets in a stream of light that spills onto his face, illuminating the feathery scars around his eyebrows and the one elongated scar wrapping around the crown of his head—the only signs of the major surgery the duo traveled 1,600 miles for.

    In a way, serendipity saved him. Dumanel, born with an extremely rare condition in one of the poorest countries in the world, found his way to a surgeon on a medical mission from Boston Children's Hospital, who recognized and diagnosed his condition on site. Dumanel, the Luxamas' first and only child, was born in Coutan, a village in the central plateau of Haiti last fall. During the delivery, it was obvious there was something unusual about his face; instead of a flat piece of skin between his dark eyebrows, he had a swollen protrusion half the size of a tennis ball.

    His father, Almane, wasn't sure what to make of it. "He was very strong," he recalls through a translator, "but he had a blob on his forehead." Almane's family believed, like local Haitian folklore suggests, that if a mother is craving something when she is pregnant, it can leave a birthmark on the child, the physical manifestation of an unsatisfied desire. But in fact, Dumanel had an encephalocele, a rare neurological defect in which the bones of the skull don't close completely during development, creating a gap through which brain tissue can protrude.

    Regardless of the cause, Almane was determined to find a remedy for his son's ailment. Two days after Dumanel's birth, Almane and Dumanel left Dumanel's mother and their humble dirt-floored home to begin a trip that would eventually take him all the way to Boston. They traveled for a full day, mostly on foot, to get to a local hospital. That hospital referred them to another. Over the next six months, they traveled to several hospitals around Haiti. Finally, Almane was told to go to the town of Hinche, where foreign doctors would be visiting in March.

    In fact, a group of doctors from the United States, including John Meara, MD, DMD, MBA, plastic surgeon-in-chief at Children's, were visiting with Operation Smile and Partners in Health (PIH), two non-profits that had teamed up to offer free reconstructive surgeries to poor children and young adults suffering from cleft lip and palate. Paul Farmer, MD, PhD, the co-founder of PIH, and Meara had trained together at Boston's Brigham and Women's Hospital in the mid-1990s. For years, Farmer had discussed with Meara the need for surgical care in Haiti, where 80 percent of the population lives under the poverty line. Like Almane, who is a farmer, two-thirds of all Haitians depend on the agricultural sector, and are vulnerable because of frequent natural disasters. Health care services and health care infrastructure do not meet the high demands of the population. Meara's curiosity was piqued; soon he was working with Farmer to meet his goal of expanding surgical care in the developing country.

    It was on Meara's second trip to Haiti that he met the Luxamas. He traveled from Port au Prince to Hinche by car, a long journey due to the decaying nature of the roads. "It might only be 100 miles, but it actually takes about six hours by car," he says. When he arrived, lines of people were waiting patiently—dozens more than the group would be able to treat. Midway down the line, Dumanel caught Meara's eye. "I could see this poor little fellow," he says, "and I could tell just from looking at him that he had a frontal encephalocele, which is quite rare."

    Though the disorder is infrequently seen in American hospitals, Meara had extensive experience with encephaloceles when he worked in Australia. "The prevalence in Southeast Asia is fairly high," he says, explaining that he had at least five cases when he worked there. "But in a decade working at a major medical center in North America, one might never see a case." Meara knew that Dumanel's chances of receiving proper medical attention for his disorder in Haiti were nil: The services needed were just not available. He also knew that few doctors, in Haiti or the United States, had any prior experience with encephalocele.

    Almane had sold his only two cows, endangering his livelihood, to fund his desperate medical search throughout the country. But he was told his journey was about to get a lot longer. He had assumed the surgery could be done on the spot at the hospital, but that was not the case. "They took a lot of pictures, and told me to go and get a passport," he says. A partnership formed: PIH, which organized and funded the visa and travel expenses; Children's, whose doctors donated their time; and the philanthropist organization Ray Tye Medical Aid Foundation, which donated money to cover hospital expenses. Five months later, the father and son had passports and were on their way to Massachusetts.

    Meanwhile, in Brockton, Mass., Hermide Mercier, MD, MPH, was preparing for the Luxamas' arrival at her home. A longtime PIH worker, Mercier shares her home with many Haitian families who come to the United States for medical help. "Partners in Health called me a couple days before and said, "We have somebody coming," she says. Before the two arrived, all their appointments at Children's had been scheduled.

    Once they made it to Children's, Dumanel's diagnosis became more complicated. During a pre-operative visit, a CT scan revealed a large arachnoid cyst, which is a fluid-filled sac, taking up almost 60 percent of the space where the right side of his brain should have been. The cyst was potentially life-threatening, as it could enlarge and put pressure on his brain. "It was fortuitous in this case that we found him, because although it's possible he could have lived for quite some time with the encephalocele, the arachnoid cyst could have given him more difficulty," Meara says.

    Neurosurgeon Ed Smith, MD, was brought in to collaborate on the surgery. The doctors had to first decide whether they should treat the two conditions in two separate surgeries, or try and do them together. After talking it over, Smith presented the case to colleagues in the Neurosurgery Department, who recommended doing both at once. The intensive surgery took a full day, and involved draining the cyst, removing the protruding brain matter from the encephalocele and repairing the defect in the skull. "The whole area around the eyes, nose and forehead was reconstructed fairly dramatically," recalls Meara.

    Almane lingered in the waiting room, unsure of what the outcome would be. "I wasn't worried at the time because I knew he was in good hands," he says. But as soon as he saw Dumanel, he got goose bumps and his heart started beating fast. "I got anxious afterwards, when they told me everything was OK," he says. "It was then that I saw the reality of what could have happened." Two months after the operation, feeding Dumanel a bottle on the couch in Brockton, Almane says he feels like heaven came down to earth to help him. "I feel like I'm delivered," he says, as Dumanel fidgets and blows milk bubbles through his lips. "I was going all over the place trying to find help. I feel so blessed. This hospital is really doing the work of God."

    Since the surgery, Dumanel's motor skills have improved rapidly. Before the surgery, he could not crawl—most likely due to his impaired vision, as the protrusion blocked his line of sight. Now, he is all over the place, with lightning speed. "He's gained weight, he's so healthy," Almane says, wiping some dribble off Dumanel's shirt. He believes that Dumanel understands something is very different about him now. "He used to touch his forehead a lot," he says. "After the surgery, he was touching it a little—now he doesn't touch it anymore. He doesn't need to turn his head to see either."

    Hermide also testifies to the amazing leaps in Dumanel's development since the surgery. "He's so different now, he's crawling and trying to talk," she says. "Before, it was so hard because he couldn't see where he was going,"

    Back at Children's, a model of Dumanel's skull (created with the data from a CT scan) sits prominently on Meara's desk. After waiting a little over two months to ensure there were no complications, the plastic surgeon gave word to Almane and Dumanel that they could go home. Dumanel's mother, who had not yet seen her son post-surgery, was anxiously waiting.

    It wasn't long before Meara saw Dumanel again, however: In December, he visited Haiti on another surgical trip, and checked on Dumanel's progress. So far, Meara is extremely pleased with the results of the surgery. "He had two very complex issues, and given that, he's done remarkably well," he says.

    That's a subdued reaction compared to that of the father who saw his son get an unlikely new chance at life: "I did not want him to have to live like that," Almane says forcefully. "I would have spent everything I had until I died, to see his head fixed."

    Editor's note: After the Boston Globe reported on Dumanel's extraordinary journey in a November article, readers responded with donations to help replace Almane's cows.

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