Type I Familial Visceral Myopathy Presenting with CT Findings of Superior Mesenteric Artery Syndrome in an Adolescent
A 13-year-old female presented with a 9-month history of intermittent nausea and nonbilious vomiting. Physical examination and a comprehensive metabolic profile were normal. Upper endoscopy revealed a dilated duodenum. Abdominal computed tomography scan showed a markedly dilated stomach and distended duodenum that narrows as it crosses between the abdominal aorta and the superior mesenteric artery, consistent with superior mesenteric artery syndrome (Fig. 1A and B).
After failure of conservative treatment, the patient underwent a laparotomy, revealing marked dilation of the stomach and duodenum to the level of the ligament of Treitz. A duodenojejunostomy was performed. Full-thickness duodenal biopsy showed markedly abnormal muscularis propria with thin, atrophic smooth muscle fibers with significant muscle loss and replacement fibrosis (Fig. 2). These findings, in conjuction with a strong family history of similar findings, were consistent with type I familial visceral myopathy.
Familial visceral myopathy I, also known as hereditary megaduodenum and hollow visceral myopathy is characterized by autosomal dominant transmission with female predominance and a propensity for clinical presentation shortly after puberty. Classic findings include esophageal dilation, megaduodenum (often with radiographic findings that mimic superior mesenteric artery syndrome), a long, redundant, occasionally dilated colon, and occasional bladder muscle involvement (1). Treatment is usually surgical, with a duodenojejunostomy, because a trial of jejunal feedings often fails (2).
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© 2009 Lippincott Williams & Wilkins, Inc.
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