Lung adenocarcinoma - occult in collapsed lung

Case contributed by Dr Bruno Di Muzio

Patient Data

Age: 50 years
Gender: Male

Chest radiographs

Left hemithorax complete whiteout with mediastinal deviation to the right. The right lung and pleural spaces are clear. 

There is a large left pleural effusion causing a total collapse of the left lung and mild rightward deviation of the mediastinal structures. The collapsed lung shows an ill-defined hypovascular area in the medial aspect of the left lower lobe, suspicious for a lung tumor. 

Nuclear medicine


Marked uptake consistent with a primary left lower lobe lung tumor with multiple pleural metastatic implants and bone metastases. 

Macroscopy: Pleural fluid - 1ml of blood-stained fluid. Cell block prepared.

Microscopy: The smears show scattered clusters of atypical epithelioid cells arranged in micropapillary and glandular formations.  The cells have enlarged, hyperchromatic nuclei with irregular nuclear membranes, prominent round nucleoli and vacuolated cytoplasm.  Macrophage, acute and chronic inflammatory cells and blood are present within the background.  An occasional group of mesothelial appearance are also seen.  Immunohistochemistry has been performed on cell block.  The atypical epithelial cell population immunoreacts with antibodies against CK 7, TTF-1 and BerEP4 and is negative with antibodies against calretinin, HBME-1, CK5/6, D2-40 and WT1.  The features are consistent with metastatic adenocarcinoma of primary pulmonary origin.

Conclusion: Pleural fluid:  Malignant.  Features consistent with metastatic adenocarcinoma of primary pulmonary origin.

Case Discussion

This case highlights how lung cancer can be identified within a collapsed normally enhancing parenchyma. But is important to emphasize that the ideal approach for cases like this one would be to perform a pleural tap based on the radiograph findings alone, with the CT scan performed after the drainage of the effusion, which increased the sensitivity of the scan in depicting possible underlying malignancies. 

The case was confirmed as a stage IVb NSCLC (TNM equivalent: any T, any N with M1c). 

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Case information

rID: 62886
Published: 13th Oct 2018
Last edited: 14th Aug 2019
System: Chest
Inclusion in quiz mode: Included

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