Microscopic description and IHC:
In addition to the increased eosinophils in the squamous mucosa, a focal submucosal nodule composed of epithelioid cells admixed with eosinophils is present. The epithelioid cells show nuclear groves under high power and stain positive for S100, CD1a, and Langerin.
Discussion:
Langerhans cell histocytosis is a rare disease with variable clinical presentation. The prognosis depends on the extent and severity of the disease. The pathogenesis of the disease is debatable and recent evidence suggest the neoplastic proliferation is derived from a myeloid-lineage precursor.
Literature reports of Langerhans cell histocytosis involving the GI tract is extremely rare.