Presentation
Cough.
Patient Data
Large bilobulated mass lesion within the right hemithorax midzone is difficult to certain if parenchymal or pleural based, the later favored given the sharp margins. Lungs and pleural spaces are clear. Mediastinal contours are normal.
Further assessment with a CT chest is recommended.
There is a large mass in the right upper hemithorax peripherally. This is closely related to the superior aspect of the right oblique fissure, and is felt most likely pleural in origin. It has a smooth, gently lobulated margin, and is centrally heterogeneous with internal hypodense areas. No internal calcification. There is no erosion or destruction of the overlying ribs and no obvious invasion of the extrapleural fat.
Two smaller pleural nodules are seen above the mass, measuring 6 mm and 5 mm in size respectively. No pleural fluid collection. There is some subtle nodularity of the left-sided pleura anteriorly. The lungs are clear. No pneumothorax.
Left and right coronary artery calcification. Borderline enlarged aortopulmonary window lymph node measuring 10 mm in short axis. Elsewhere there are no enlarged hilar or mediastinal lymph nodes.
Multiple hypodense liver lesions compatible with cysts.
Conclusion:
The large mass in the right upper thorax favored pleural. A pleural neoplasm is most likely, with differentials including fibrous tumor and metastasis. Mesothelioma is felt less likely. A primary lung lesion extending into the pleural is also less likely, though
is not excluded.
Respiratory referral and discussion at the multidisciplinary meeting are advised, as is a further assessment with PET and consideration of biopsy.
Macroscopy: Labeled "Right pleural/lung biopsy". Multiple pale tan needle core biopsies 2-11 mm.
Microscopy: The biopsy cores show malignant tumor within sclerotic fibrous tissue. The tumor is composed of a haphazard arrangement of spindle cells with large, hyperchromatic pleomorphic nuclei and prominent nucleoli. Mitotic figures are fairly frequent, including atypical forms. There is partial tumor necrosis. No keratinization or glandular formations are seen. No alveolated lung tissue is present.
Immunoperoxidase stains have been performed and the tumor cells show strong diffuse staining for CD99. There is no tumor cell staining for cytokeratin mix, CK 5/6, TTF-1, CD34, HBME1, calretinin, WT1 or p40. Additional immunostains are in progress.
Conclusion: Right pleural/lung, core biopsy: Sarcomatoid malignancy.
Additional immunostains have been performed and the tumor cells show strong positive staining for vimentin, with no staining for broad-spectrum cytokeratin (AE 1/3), EMA, BCL2, STAT6, S100 or desmin.
Based on this limited sample, the favored diagnosis is of synovial sarcoma. Sarcomatoid carcinoma and mesothelioma have been considered, however, there is no tumor cell staining for cytokeratin or mesothelial markers to support these diagnoses.
This case was sent to another tertiary center pathologist for review, who concurs with the diagnosis of sarcomatoid malignancy.
Case Discussion
A case illustrating a rare sarcomatoid pleural malignancy in an elderly patient. Further staging with CT abdomen/pelvis and FDG PET-CT did not show metastatic disease (images not shown). Management was taken for neoadjuvant treatment with radiotherapy and further surgical resection with curative intent.
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