# Vanishing Lung Syndrome in a Dog: Giant Pneumatocele or Giant Pulmonary Bulla Mimicking Tension Pneumothorax—First Report

## TL;DR

A 6-month-old dog showed symptoms similar to vanishing lung syndrome, with a large air cavity in the chest that resolved without surgery.

## Contribution

First reported case of vanishing lung syndrome in a dog, mimicking tension pneumothorax.

## Key findings

- Thoracic radiographs showed a large air-filled cavity mimicking tension pneumothorax.
- Conservative treatment led to complete resolution of the lesion without surgery.
- The case was retrospectively diagnosed as a giant pneumatocele rather than a pulmonary bulla.

## Abstract

This article presents the case of a 6-month-old Belgian Malinois dog admitted for severe respiratory distress evolving over 24 h. Thoracic radiographs revealed a large intrathoracic air-filled cavity, initially interpreted as a giant pulmonary bulla which appeared responsible for compressive pulmonary collapse in the absence of spontaneous pneumothorax. This presentation closely resembles the vanishing lung syndrome described in human medicine. Emergency thoracocentesis followed by thoracostomy tube placement led to rapid clinical improvement, without the need for surgical intervention. The complete resolution of the lesions under conservative treatment led to a retrospective reassessment, considering the possibility that it was not a giant bulla but perhaps a giant pneumatocele.

A 6-month-old neutered male Belgian Malinois dog living in a kennel was presented to a veterinary emergency service for the management of severe respiratory distress that had developed within the past 24 h. Thoracic radiographs performed by a referring veterinarian showed abnormalities identified as a pneumothorax. Upon admission to the emergency service, the striking anomalies turned out to be a large intrathoracic air-filled cavity and countless smaller ones causing mechanical compression of the adjacent pulmonary parenchyma and mimicking tension pneumothorax. Emergency management included thoracocentesis followed by placement of a thoracostomy tube. The dog exhibited rapid clinical improvement and recovered completely within a few days, without requiring surgical intervention. Serial follow-up radiographs showed progressive and complete resolution of all lesions. Based on the complete resolution without resection, the main lesion—initially interpreted as a giant pulmonary bulla—was ultimately considered consistent with an acquired pneumatocele. To the authors’ knowledge, this is the first report in veterinary medicine of a vanishing lung syndrome presentation in a dog.