6 Patterns > Alveolar Filling

Alveolar Filling

You have selected the alveolar filling pattern!

Patients with alveolar filling pattern biopsies typically present acutely or sub-acutely with cough and SOB over months to years. The imaging studies show ground glass infiltrates or areas of consolidation (the radiologic correlate of alveolar filling). Airspaces should be filled from scanning magnification. The biopsy may be blue or pink, depending on what is in the air space. If you still think you have an alveolar filling pattern biopsy, click the link below.

Investigate Subcategories in the Alveolar Filling Pattern

If you're still unsure if you're dealing with an alveolar filling pattern, explore other histologic features below. All of the cases below have abnormal alveoli filling.

Edema

In early acute lung injury, edema with hyaline membranes is the dominant histology. These biopsies have a light pink appearance and may look normal at first glance.

Fibrin in Airspaces

Fibrin can be the dominant histology filling airspaces, even in the absence of hyaline membranes. This pattern of injury has been referred to as Acute and Fibrinous Organizing Pneumonia (AFPO).

Organizing Acute Lung Injury

As DAD organizes, the fibrin, hyaline membranes, and polyps of OP fill air spaces.

Polyps of Organizing Pneumonia

The classic airspace filling pathology.

Mixed Pattern: Cellular infiltrates with Air Space Filling

This case of CTD associated ILD shows an acute fibrinous pneumonia with a background cellular lymphoplasmacytic infiltrate.

If your biopsy has the above features, you are in the appropriate category of alveolar filling. But your job is not complete by recognizing alveolar filling.

Explore additional histologic features in the alveolar filling pattern to further clarify the diagnosis

Sample Signout

If no additional specific histologic features are identified, consider the following approach to signing the case out:

Extensive alveolar filling by _______ (see comment).

Comment: The biopsy shows extensive filing of the alveoli by ________. The differential diagnosis included _______ (from the next page). Correlation with imaging studies, serology, microbiology studies, and clinical history is suggested.