# Pulmonary Nodular Lymphoid Hyperplasia Presenting With a Reversed Halo Sign

## TL;DR

A rare lung condition called pulmonary nodular lymphoid hyperplasia was found to present with a reversed halo sign, a feature previously not associated with this disease.

## Contribution

This is the first reported case linking pulmonary nodular lymphoid hyperplasia with the reversed halo sign on chest CT.

## Key findings

- A case of pulmonary nodular lymphoid hyperplasia presented with a reversed halo sign on imaging.
- Histological analysis confirmed a polyclonal reactive lymphoid proliferation without IgG4-positive cell increase.
- The case suggests that PNLH should be considered in the differential diagnosis of the reversed halo sign.

## Abstract

The reversed halo sign is observed in a broad spectrum of lung diseases, most commonly organising pneumonia, but it has not been reported in pulmonary nodular lymphoid hyperplasia. Herein, we describe the first case of pulmonary nodular lymphoid hyperplasia presenting with a reversed halo sign.

We report a case of pulmonary nodular lymphoid hyperplasia (PNLH) presenting with a reversed halo sign on chest computed tomography. Video‐assisted thoracoscopic wedge resection confirmed a polyclonal reactive lymphoid proliferation without an increase in IgG4‐positive cells. This case highlights that PNLH should be considered in the differential diagnosis of the reversed halo sign and that histologic confirmation is essential.