IgG4-related disease (IgG4-RD) is a recognized systemic fibro-inflammatory condition characterized by a dense lymphoplasmacytic infiltrate rich in IgG4-positive cells and storiform fibrosis. Although initially described in pancreatic affections in 2001 and 2003, it is now known to affect virtually every organ, including the biliary tract, salivary glands, pancreas, kidneys, lungs for example, and  rarely, the esophagus.

Diagnosis relies on a constellation of criteria: elevated serum IgG4 levels , characteristic histopathology (lymphocytic infiltration, obliterative phlebitis, and storiform fibrosis with organ-specific diagnostic criteria), and location.

We report the case of a 47-year-old female patient with a medical history including three episodes of acute pancreatitis, two episodes of pyelonephritis, and insulin-requiring type 2 diabetes. She presented for evaluation of dysphagia that had been evolving over two years. Endoscopy revealed a benign appearing stricture impassable by an adult endoscope. An upper gastrointestinal series and an abdominal CT scan confirmed the presence of marked esophageal wall thickening and a regular stricture in the middle third of the esophagus. A subsequent PET-CT scan showed an isolated hypermetabolism of the esophageal walls, suggestive of an oncological or an inflammatory process.

Endoscopic ultrasound  (EUS) was performed due to parietal mucosal thickening, followed by submucosal wall tissues acquisition with fine needle biopsy (FNB). Histological results from the FNB demonstrated a lymphoplasmacytic infiltrate with an IgG4 quantification of 22 cells per 40x high-power field (HPF), highly suggestive for the diagnosis of IgG4-RD. Screening for other organ involvement revealed suspected renal and myocardial affection. Treatment with corticosteroids (dose?) was significantly delayded due to the presence of latent tuberculosis infection and poorly controlled diabetes, which was further dyregulated by the use of corticosteroids. A concomitant corticosteroid-sparing regimen with azathioprine was attempted in view the adverse effects associated with corticosteroid treatment but did not lead to clinical improvement. Ultimately, treatment with Rituximab was initiated after 9 months, resulting in the beginning of symptomatic improvement.

This case highlights, a rare cause of dysphagia (esophageal IgG4-RD) and, the significant difficulty in managing this condition due to the patient's complex comorbidities (diabetes, latent tuberculosis). The certainty of the diagnosis and the follow-up of the treatment in this case necessitate a multidisciplinary approach and close cooperation.