# A Case of Autoimmune Pulmonary Alveolar Proteinosis With Predominantly Peripheral Opacities Diagnosed by Transbronchial Lung Biopsy

## TL;DR

A rare case of autoimmune pulmonary alveolar proteinosis with unusual peripheral lung shadows was diagnosed using a biopsy and antibody testing.

## Contribution

This case highlights the importance of considering PAP in subpleural lung shadows and using TBLB and anti-GM-CSF antibody testing for accurate diagnosis.

## Key findings

- Autoimmune PAP can present with subpleural ground-glass shadows in the upper lobes.
- Transbronchial lung biopsy confirmed the diagnosis in this atypical case.
- Anti-GM-CSF antibody positivity supported the autoimmune nature of the disease.

## Abstract

Although pulmonary alveolar proteinosis (PAP) showed various shadows, its shadows are usually distributed predominantly in the central lung area. We report a case of autoimmune PAP with localized subpleural ground-glass shadows in the bilateral upper lobes, which was diagnosed based on transbronchial lung biopsy (TBLB) specimen findings and anti-granulocyte macrophage colony PAP stimulating factor antibody positivity. PAP should be listed as a differential diagnosis for subpleural shadows. If subpleural shadows are observed, TBLB should be performed aggressively, and anti-granulocyte macrophage colony-stimulating factor (anti-GM-CSF) antibodies should be submitted.