Esophageal lymphocytosis: exploring the knowns and unknowns of this pattern of esophageal injury.

Lymphocyte-rich inflammation of the esophageal mucosa has gained increased awareness among pathologists and clinicians recently. Patients usually present with symptoms of esophageal dysfunction, including dysphagia and food bolus impaction. Endoscopy may show changes similar to eosinophilic esophagitis but may also be entirely normal ('microscopic esophagitis'). Three morphological subtypes or variant forms have been described which include lymphocytic, lichenoid and lymphocyte-predominant esophagitis. These need to be discriminated against other distinct causes of esophageal lymphocytosis, such as gastro-esophageal reflux disease and Candida infection. This review provides an overview of diagnostic criteria and clinical associations of the disorder and presents an algorithmic approach to diagnosis. A comprehensive literature review was conducted using PubMed, Medline and Google Scholar databases to identify articles related to lymphocyte-rich esophageal inflammation, published up to March 2024. Lymphocyte-rich inflammation needs to be included in the differential diagnosis and clinical work-up of patients with esophageal dysfunction. There is currently considerable morphological overlap among published subtypes or variant forms. Follow-up studies of affected individuals are needed to formalize diagnostic parameters and identify the clinical course of disease in order to optimize treatment modalities.