Epithelioid mesothelioma

Case contributed by Dr Bruno Di Muzio

Presentation

Chest pain and shortness of breath.

Patient Data

Age: 70 years
Gender: Male
X-ray

Chest

There is diffuse left hemithorax nodular pleural thickening encasing the lung and with, perhaps, some left hemithorax volume loss. A component of pleural effusion cannot be excluded. Three small coils projected within the left hemithorax infer previous surgical intervention. The right lung and pleural space are clear. Enlarged left paratracheal stripe either represents lymphadenopathy or pleural mass component. 

Chasing for previous imaging or further CT recommended. 

CT

CTPA

Right lower lobe superior segment and left lower lobe lateral basal segment non-occlusive emboli. Heart size normal. No CT features of right heart strain.

Nodular gross pleural thickening that encases the left lung is certainly malignant and appears to invade pericardium. No invasion of the left atrium or ventricle apparent. Multiple nodules and soft tissues masses at the left lung base will be a combination of pleural and parenchymal disease. Peribronchovascular thickening extending to the left hilum. New mediastinal and left hilar lymphadenopathy.

Multinodular goiter.

Conclusion:

  • Bilateral non-occlusive segmental pulmonary emboli. No CT features of right heart strain.
  • Left hemithorax features almost certainly represent mesothelioma. Mediastinal lymphadenopathy and features suspicious of pericardial invasion.

Case Discussion

This patient was known to have confirmed pleural malignancy followed up in another service. 

He has previous left VATS: Macroscopy: Labeled "Left pleural rind biopsy".  2 fragments of fatty tissue bearing an incomplete smooth pale grey lining 8 x 5 x 3 mm and 14 x 9 x 5 mm.  Inked, serially sliced.

Microscopy: The biopsy fragments show fibroadipose connective tissue with surface fibrinous exudate. Within the submesothelial stroma, there is a proliferation of atypical epithelioid mesothelial cells forming small nests, trabeculae, and tight acinar arrangements. These cells have moderately pleomorphic nuclei with prominent nucleoli and there are scattered mitotic figures. A sclerotic stromal reaction is present. The surrounding pleural tissue shows features of fibrous pleuritis with mild chronic inflammation. No alveolated lung tissue is included. Atypical cells do not extend into the adipose.
Immunoperoxidase stains have been performed on the mesothelial cells show positive staining for calretinin and CK 5/6, with no staining for EMA.
The findings are suspicious for malignant mesothelioma, however, the presence of adjacent fibrous pleurisy and the absence of invasion into the adipose tissue precludes a definite diagnosis.

Conclusion: Left pleural rind biopsy: Atypical mesothelial proliferation, suspicious for but not diagnostic of mesothelioma.

A second opinion from a different pathologist: features are in keeping with malignant mesothelioma, epithelioid subtype. 

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Case information

rID: 75229
Published: 30th Apr 2020
Last edited: 2nd Aug 2021
System: Chest
Inclusion in quiz mode: Included

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