# Gastrointestinal pathology in Good’s syndrome, thinking beyond common variable immunodeficiency: a clinicopathological observation

## TL;DR

Good’s syndrome, a rare immunodeficiency linked to thymoma, shows unique gastrointestinal pathology that can be mistaken for common variable immunodeficiency.

## Contribution

This study highlights distinct gastrointestinal features in Good’s syndrome, aiding in differentiation from CVID.

## Key findings

- GS cases showed reduced plasma cells in multiple gastrointestinal sites.
- Chronic norovirus infection and invasive adenocarcinoma were observed in GS patients.
- Accurate diagnosis of GS is critical due to its worse prognosis compared to CVID.

## Abstract

Good’s syndrome (GS) is a rare immunodeficiency associated with thymoma, characterized by increased susceptibility to bacterial, viral, and fungal infections, along with autoimmune manifestations. Gastrointestinal symptoms are common in GS, yet its clinical and histopathological features remain underrecognized. Due to significant overlap in clinical presentation and immunological profiles, GS is frequently misdiagnosed as common variable immunodeficiency (CVID). While gastrointestinal pathology in CVID has been well-documented, data on gastrointestinal manifestations in GS are limited. In this study, we analyzed two cases of GS, both demonstrating marked reduction of plasma cells across multiple gastrointestinal sites, with variable intraepithelial lymphocytosis and mild to moderate villous blunting in the duodenum and features secondary to chronic norovirus infection in one case, and an invasive adenocarcinoma with notable depletion of lamina propria plasma cells in the other. Accurate recognition of GS is essential for pathologists and clinicians, given its poorer prognosis compared to CVID.