Category: Chronic inflammatory, non-neoplastic disease of the esophagus.
Essence: Immune/antigen-mediated Th2-type esophagitis characterized by intraepithelial eosinophil-rich inflammation.
Demographics: Affects both children and adults, often with atopic background (asthma, allergic rhinitis, eczema).
Clinical presentation: Dysphagia, food impaction, feeding intolerance, chest discomfort.
Distribution: Diffuse involvement, often more severe in the proximal esophagus.
Antigen exposure (food or aeroallergen) → activates Th2 lymphocytes → ↑ IL-5, IL-13, eotaxin-3 → recruitment of eosinophils to esophageal mucosa → degranulation and epithelial injury → basal cell hyperplasia + lamina propria fibrosis → chronic inflammation and “trachealization” of esophagus.
Key diagnostic feature: ≥15 intraepithelial eosinophils per high-power field (HPF).
Additional features:
Eosinophilic microabscesses (clusters of eosinophils).
Superficial layering of eosinophils with degranulation.
Basal cell hyperplasia (>20% of epithelial thickness).
Intercellular edema (spongiosis) and elongated papillae.
Lamina propria fibrosis in chronic disease.
Endoscopic clues: Concentric rings (“trachealization”), linear furrows, and white plaques (exudates).
Diagnosis: Primarily H&E-based; immunostains rarely required.
IHC: Eosinophils highlighted by major basic protein if needed for confirmation.
Molecular: No defining genetic alteration; Th2 cytokine overexpression (IL-13, eotaxin-3) supports allergic pathway.
Gastroesophageal reflux disease (GERD): Can show mild eosinophilia but usually limited to the distal esophagus with fewer than 15 eosinophils per HPF. Lamina propria fibrosis and superficial eosinophilic layering—hallmarks of EoE—are absent.
Pill-induced esophagitis: Produces ulceration with necrotic debris and often polarizable pill fragments or crystalline material. The inflammation is usually localized and not diffusely eosinophil-rich.
Infectious esophagitis (HSV or CMV): Shows viral cytopathic changes—multinucleation, nuclear inclusions (HSV), or cytomegalic cells (CMV). Neutrophils predominate rather than eosinophils.
Lymphocytic esophagitis: Features dense intraepithelial lymphocytes with minimal or absent eosinophils. The infiltrate forms a band-like pattern near the epithelial surface.
Esophagitis dissecans superficialis: Characterized by sloughing necrotic squamous epithelium that may peel off in sheets. The underlying mucosa shows little active inflammation, distinguishing it from EoE.
Esophagus, biopsy:
- Chronic eosinophil-rich esophagitis (>15 eosinophils per HPF), consistent with eosinophilic esophagitis (clinical correlation recommended).