Mesothelioma - subtle nodular thickening of the interlobar fissures

Case contributed by Dr Bruno Di Muzio

Presentation

Shortness of breath. Recurrent pleural effusion on the right.

Patient Data

Age: 70 years
Gender: Female

Small right pleural effusion associated with faint airspace opacities within the base of the right lung. The left lung and pleural spaces appear clear, cardiomediastinal contours are normal. 

There is a small right-sided pleural effusion. The right hemidiaphragm shows an uneven surface due to some small soft tissue nodules. The horizontal and right oblique fissures are slightly thicker and have a nodular appearance when compared to the contralateral oblique fissure. Apart from mild centrilobular emphysematous changes in both upper lobes, the lungs are unremarkable. Right hilum prominent lymph node measuring up to 9 mm in its short axis. The remainder of the chest is unremarkable. 

Blue arrows showing the nodularity covering the right hemidiaphragm. Yellow arrows pointing the subtle fissural thickening due to nodularity. 

Macroscopy:  "Right pleura biopsy".  A fragment of soft, tan tissue bearing 1 soft, nodular surface, the other surface is shiny with attached ragged fatty tissue 30 x 22 mm, 8 mm thick. Fatty surface inked blue. 

Microscopy: The sections show fragments of skeletal muscle and fibroadipose connective tissue lined by mesothelium. The mesothelium is thrown into exuberant folds and pseudo-papillary structures about underlying myxoid and chronically inflamed stroma. The cells have enlarged nuclei with irregular nuclear membranes, vacuolated chromatin and prominent round nucleoli. Scattered mitoses are identified. The cells, arranged in variably sized glandular and cribriform structures and solid nests, appear to infiltrate the underlying connective tissues, including fat. 

Immunohistochemistry: The atypical cell population immunoreacts with antibodies against CK5/6, podoplanin, HBME1, calretinin and WT1 and is negative with CK7, CK20, TTF1 and TAG-72.

Conclusion:  Malignant mesothelioma.

Case Discussion

This case illustrates early CT findings of mesothelioma involving the right hemithorax and characterized by micronodules covering the hemidiaphragm and slightly thickening the fissures. Given the pleural effusion was recurrent, the patient underwent a pleural tab after the radiograph and cytology showed some malignant cells, a further pleural biopsy confirmed mesothelioma. Note that there are no calcified pleural plaques. 

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Case information

rID: 60153
Published: 9th May 2018
Last edited: 9th May 2018
System: Chest
Inclusion in quiz mode: Included

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