Microvillus Inclusion Disease

Definition

Severe intractable diarrhea presents in first week of life
- Rarely as late as 60 days
Severe villous atrophy
- No crypt hyperplasia
- No inflammation
PAS/d, polyclonal anti-CEA, CD10 stains highlight microvillus abnormalities in small intestine
- Loss of brush border
- Apical cytoplasmic positivity
  - May be recognizable as microlumina
Electron microscopy reveals loss of brush border and presence of apical cytoplasmic microlumina lined by microvilli
Autosomal recessive
Rare

Presentation at birth, lack of inflammation and presence of intracytoplasmic microlumina exclude other causes of villous atrophy and diarrhea

Tufting Enteropathy	Microvillus Inclusion Disease
Surface epithelial tufts	Apical cytoplasmic inclusions

Both may have scant inflammation with villous atrophy

Enteroendocrine Cell Dysgenesis	Microvillus Inclusion Disease
Normal villi	Severe villus atrophy
Intestinal endocrine cells markedly decreased or absent	Normal intestinal endocrine cells
Normal enterocyte cytoplasm	PASd positive apical cytoplasmic inclusions (microlumena)
Normal brush border	Loss of brush border
Markedly decreased or absent endocrine cells	Endocrine cells present

Both present with neonatal diarrhea and lack significant inflammation

Microvillus Inclusion Disease	Abetalipoproteinemia
Apical cytoplasmic microlumena	Foamy cytoplasm filled with fat vacuoles
Severe villus atrophy	Normal villus length

Both present with neonatal diarrhea and lack significant inflammation

Groisman GM, Amar M, Livne E. CD10: a valuable tool for the light microscopic diagnosis of microvillous inclusion disease (familial microvillous atrophy). Am J Surg Pathol. 2002 Jul;26(7):902-7.
Phillips AD, Schmitz J. Familial microvillous atrophy: a clinicopathological survey of 23 cases. J Pediatr Gastroenterol Nutr. 1992 May;14(4):380-96.
Shillingford NM, Calicchio ML, Teot LA, Boyd T, Kurek KC, Goldsmith JD, Bousvaros A, Perez-Atayde AR, Kozakewich HP. Villin immunohistochemistry is a reliable method for diagnosing microvillus inclusion disease. Am J Surg Pathol. 2015 Feb;39(2):245-50. doi: 10.1097. PubMed PMID: 25517957.
Martin BA, Kerner JA, Hazard FK, Longacre TA. Evaluation of intestinal biopsies for pediatric enteropathy: a proposed immunohistochemical panel approach. Am J Surg Pathol. 2014 Oct;38(10):1387-95. doi: 10.1097. PubMed PMID: 25188866.

Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342