A 7-year-old girl had three weeks of on-and-off upper belly pain, felt full after eating very little, and had lost 4.5 kilograms, nearly 10 pounds. An MRI and a specialized X-ray study both pointed her doctors toward a rare condition in which part of the small intestine is squeezed near a major artery. The real culprit was a hairball nearly 4 inches long.
The case, published Feb. 26 in Frontiers in Pediatrics by physicians at The Valley Hospital and Valley Medical Group in Paramus, New Jersey, shows how a gastric trichobezoar, a mass of swallowed hair in the stomach, closely mimicked superior mesenteric artery (SMA) syndrome across multiple imaging tests.
The previously healthy girl was eating poorly, although she was drinking enough fluids. She had no vomiting or diarrhea.
Imaging Pointed Toward SMA Syndrome
Her blood work showed a mildly elevated platelet count, slightly elevated lipase, a digestive enzyme, and iron deficiency, with iron saturation of just 5%. She had no fever and normal vital signs, but her abdomen was tender throughout. An abdominal X-ray and an ultrasound were normal.
Because of her persistent symptoms and weight loss, doctors ordered an MRI, which avoids the radiation of a CT scan. The MRI showed significant stretching of the stomach and the duodenum, the first part of the small intestine, with apparent narrowing where the superior mesenteric artery crosses the duodenum. The findings were interpreted as suggestive of SMA syndrome.
SMA syndrome is a rare cause of blockage in which the duodenum is compressed, often after loss of the fat pad that normally cushions it. According to the report, it primarily affects young females and shares several symptoms with trichobezoars, including nausea, vomiting, upper abdominal pain, and early fullness.
An upper gastrointestinal X-ray series added to the confusion. It showed delayed stomach emptying and a dilated duodenum that improved with position changes, findings that reinforced the working diagnosis.
A Camera Found What the Scans Missed
One clue did not fit. A persistent filling defect in the stomach on the X-ray study raised concern that something was inside it. Because the imaging findings did not match the severity of her symptoms, doctors performed an upper endoscopy, passing a camera into her stomach.
They found a large trichobezoar with ulceration around it in the main body of the stomach. The ulceration explained her iron deficiency, the authors wrote.
Because of the mass’s size and density, doctors did not attempt to remove it through the scope. Pediatric surgeons instead used a laparoscopic-assisted procedure to open the stomach and pulled out the hairball in one piece. It measured 10.0 by 3.2 by 3.0 centimeters.
Her recovery was uncomplicated. She went home eating by mouth and taking an acid-reducing medication for the ulcer. At a one-week follow-up, she was eating well, had regained 2.3 kilograms, about 5 pounds, and had no further abdominal symptoms.
A Hidden Habit Came to Light After Diagnosis
Trichobezoars are strongly associated with trichotillomania, a compulsive urge to pull out hair, and trichophagia, the compulsive eating of hair. In this case, neither behavior was obvious at first.
Only after the diagnosis did her parents report that she had a habit of sucking on and swallowing her hair during periods of anxiety. The authors note that neither the girl nor her parents mentioned it at first, and that the absence of visible hair loss or a known psychiatric history delayed suspicion.
She was referred for outpatient behavioral health care, and her parents were counseled on ways to monitor the habit and lower the risk of recurrence. No further hair-eating was reported at the one-week follow-up.
The authors stress that long-term outcomes depend on addressing the underlying behavior, which calls for teamwork among pediatric surgery, gastroenterology, and behavioral health specialists.
Why Hairballs Can Slip Past Imaging
According to the report, trichobezoars occur in less than 1% of children, mostly girls, and imaging often struggles to identify them. Plain X-rays detect only 10% to 18% of bezoars, and trapped air and food can limit ultrasound.
Contrast-enhanced CT is the preferred test, with reported sensitivity of up to 90%, according to a review of bezoar diagnosis and treatment that the authors cite. In this case, CT was deferred because of radiation concerns in a young child. MRI avoids radiation, but evidence for its accuracy in detecting bezoars is limited, and large hairballs can appear as dark areas that are mistaken for air in the stomach. In this girl, the MRI showed no distinct mass inside the stomach.
In retrospect, the authors wrote, the team anchored on SMA syndrome based on symptoms and imaging features rather than definitive proof that the artery was compressing the bowel. The key difference is mechanical: SMA syndrome involves pressure from outside the bowel, while a trichobezoar blocks it from within. Endoscopy remains the gold standard for diagnosing trichobezoars.
Left undetected, hairballs can extend past the stomach into the small intestine, a form known as Rapunzel syndrome. The report notes that this variant raises the risk of ulceration, bleeding, bowel damage, and perforation. A case report and literature review in the same journal describes Rapunzel syndrome as an extremely rare cause of digestive symptoms in children.
The new report describes one child, so it cannot show how often trichobezoars are mistaken for SMA syndrome. Parents who notice a child chewing or swallowing hair, especially alongside stomach pain, early fullness, or weight loss, should raise it with a pediatrician.
Key Questions Answered
What is a trichobezoar?
It is a mass of swallowed hair that builds up in the stomach because hair resists digestion and the stomach’s normal muscular movements.
Why did doctors first suspect SMA syndrome?
An MRI and an upper gastrointestinal X-ray series showed a stretched stomach and duodenum with apparent narrowing near the superior mesenteric artery, which fit that diagnosis.
How was the hairball found and removed?
An upper endoscopy revealed the hairball, and surgeons removed it in one piece through a laparoscopic-assisted opening in the stomach.
What warning signs should parents know?
Hair chewing or swallowing combined with stomach pain, early fullness, poor appetite, or unexplained weight loss should prompt a visit to a pediatrician.
Can hairballs come back?
The risk remains if the underlying habit continues, which is why the girl was referred for behavioral health care after surgery.
