Pancytopenia as the Initial Presentation of Celiac Disease.

Celiac disease is an immune-mediated enteropathy precipitated by gluten in genetically susceptible individuals. Although diarrhea, weight loss, and malabsorption are classical features, extraintestinal presentations are increasingly recognized. Pancytopenia as the initial manifestation of adult celiac disease is rare and often delays diagnosis. We report a 39-year-old woman from Assam, Northeast India, who presented with chronic diarrhea, weight loss, and progressive weakness, and was found to have severe pancytopenia (hemoglobin 3.9 g/dL, leukocytes 1,200/mm3, and platelets 23,000/mm3). Iron studies suggested iron deficiency. Despite a normal serum vitamin B12 level (874 pg/mL), markedly elevated methylmalonic acid (1,600 nmol/L) and homocysteine (56.8 μmol/L) confirmed functional B12 deficiency. Anti-tissue transglutaminase immunoglobulin A was equivocal, but duodenal biopsy demonstrated partial villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes (Marsh 3A). Peripheral blood flow cytometry was notable for lymphopenia with elevated T-cell receptor αβ+ double-negative T cells (2.59%), a finding of immunological interest. A gluten-free diet with iron, folate, and parenteral B12 supplementation produced rapid clinical and hematological recovery within 3 weeks. At 3-week follow-up, all 3 lineages had improved (hemoglobin 10.4 g/dL, total leukocyte count 3,800/mm3, and platelets 170,000/mm3 by manual count; the platelet count had normalized while hemoglobin and leukocytes were improving but not yet fully normalized). This case underscores celiac disease as a reversible cause of unexplained pancytopenia, highlights the limitations of serum B12 and serology in equivocal presentations, and adds to the limited literature on celiac disease from Northeast India-a region where the condition remains substantially underdiagnosed.