Neurofibromatosis-associated Malabsorption

Abstract

We report on a case of a young woman who presented with anemia secondary to malabsorption in the setting of neurofibromatosis with intestinal involvement. A 25-year-old woman presented with symptomatic iron deficiency anemia. There was no history of menorrhagia or pregnancy and she was eating a regular diet. For the prior 18 months, she suffered from diarrhea and weight loss. Her family history was significant for both her mother and brother having neurofibromatosis type 1. She, herself, had been previously diagnosed with neurofibromatosis based on café au lait spots. Her exam was significant for several café au lait spots, a 2.5cm neurofibroma on the chest, a firm yet non-tender abdomen, and a body mass index of 17.3. Labs revealed a microcytic anemia of 6.4g/dL with an associated ferritin of 2.7ng/mL. Further laboratory testing revealed a low serum copper of 29μg/dL, hypoalbuminemia of 2.0g/dL, and a low 25-OH vitamin D at 6.1ng/mL. Thiamine, vitamin E, vitamin B12, folate and IgA tissue transglutaminase were normal. A CT scan showed multiple segments of severely thickened jejunal and ileal loops. Some areas contained polypoid luminal masses. A conglomeration of low-density masses was noted throughout the small bowel mesentery (Figure 1). The terminal ileum and proximal duodenum were not involved. A subsequent diagnostic push enteroscopy revealed markedly dilated lacteals in the jejunum (Figure 2). Jejunal biopsies confirmed diffuse mucosal involvement by neurofibroma with associated dilated lacteals (Figure 3). This led to a diagnosis of small bowel neurofibromatosis-associated malabsorption. Neurofibromatosis type 1 is an autosomal dominant condition associated with gastrointestinal tumors in up to 25% of cases.1 Neurofibromatosis causing lymphatic obstruction of the extremities with resultant lymphedema is well reported. Neurofibromatosis involving the small bowel may present with occult bleeding, intussusception, or constipation.3-5 In the case described here, infiltration of the mesentery as well as the small bowel with neurofibromatosis resulted in dilated lacteals, associated hypoalbuminemia, as well as multiple vitamin deficiencies. The patient's anemia and copper improved with parenteral iron and copper supplementation, but her hypoalbuminemia and diarrhea persisted. Because of extensive small bowel involvement, surgical resection was deferred and she was referred to a nutritionist for dietary manipulation.Figure: CT demonstrating segments of thickened jejunal and ileal loops, polypoid luminal masses. and a conglomeration of low-density masses throughout the small bowel mesentery.Figure: Push enteroscopy revealing markedly dilated lacteals in the jejunum.Figure: Jejunal biopsies showing diffuse neurofibroma with dilated lacteals.