Alveolar-filling growth pattern of sarcomatoid malignant pleural mesothelioma

Our plain-English summary of Alveolar-filling growth pattern of sarcomatoid malignant pleural mesothelioma, by T. Hayakawa, S. Tajima, Y. Takanashi, et al (Respirology Case Reports, 2016).

The study

• Authors: T. Hayakawa, S. Tajima, Y. Takanashi, T. Takahashi, H. Neyatani, K. Funai
• Journal: Respirology Case Reports
• Published: 2016;4(5):e00175
• Type of article: Case report
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

A case of sarcomatoid malignant pleural mesothelioma showing extremely rare growth pattern is described. A 63-year-old man presented to our hospital with left pleural effusion. A computed tomography (CT) scan of the chest showed diffusely thickened left visceral and parietal pleura associated with intermingled pulmonary infiltrative shadowing. Biopsy of the pleura under general anaesthesia confirmed the diagnosis of sarcomatoid malignant pleural mesothelioma. The patient underwent left extra-pleural pneumonectomy. Histopathologically, the sarcomatoid spindle tumour cells changed their morphology to polygonal cells in the pulmonary parenchyma and grew upwards, filling the alveolar space without the destruction of its septa, showing an alveolar-filling growth pattern. The current report indicates a case of sarcomatoid pleural mesothelioma that shows an alveolar-filling growth pattern, despite having not been thoroughly categorized in the World Health Organization (WHO) classification.

In plain English

This case report described a 63-year-old man who came to the authors' hospital with fluid around the left lung (left pleural effusion). A CT scan showed thickened left pleura with infiltrative shadowing in the lung, and a pleural biopsy confirmed sarcomatoid malignant pleural mesothelioma. Further scans found no distant spread, and the disease was diagnosed as stage III (c-T3N2M0). The patient underwent left extra-pleural pneumonectomy, but the tumour was non-resectable because of peritoneal spread beyond the diaphragm and invasion of the descending aorta. The patient had a cardiopulmonary arrest after surgery and died on postoperative day 39 from multiple organ failure. Under the microscope, spindle-shaped tumour cells along the pleura became polygonal cells inside the lung and filled the air sacs (alveoli) without destroying their walls. These polygonal cells stained positive for epithelial membrane antigen (EMA) and the spindle cells did not. Both cell types stained for CK5/6 and calretinin. The authors concluded that this rare alveolar-filling growth pattern exists, although it is not described in the current WHO classification. The article did not report any asbestos exposure history.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: case report (single patient)
• Who was studied: One 63-year-old man who presented with left pleural effusion at the authors' hospital. The first author is affiliated with Fujieda Municipal General Hospital, Shizuoka, Japan. No dates are given.
• Exposure: Not reported. The article does not mention asbestos or any other exposure history for the patient.
• Main results:
  • A pleural biopsy under general anaesthesia confirmed the diagnosis of sarcomatoid malignant pleural mesothelioma.
  • Positron emission tomography-computed tomography and magnetic resonance imaging found no distant metastatic lesions in other organs.
  • The patient was then diagnosed with stage III c-T3N2M0 sarcomatoid malignant pleural mesothelioma.
  • At left extra-pleural pneumonectomy, the tumour was non-resectable because of peritoneal dissemination beyond the diaphragm and direct invasion of the descending aorta.
  • The patient had a cardiopulmonary arrest due to lethal arrhythmia after surgery and died on postoperative day 39 of multiple organ failure.
  • Once the spindle tumour cells had entered the lung tissue, they changed to polygonal cells forming clusters that filled the alveolar spaces.
  • The alveolar-filling cells spread through the pores of Kohn into neighbouring alveoli without destroying the alveolar septa.
  • CK5/6 and calretinin were diffusely expressed in both the spindle and the polygonal tumour cells.
  • The spindle tumour cells were negative for epithelial membrane antigen (EMA), while the polygonal cells were positive for EMA.
  • The authors interpreted the infiltrative shadow on CT as reflecting the tumour cells that had invaded the lung and filled the alveolar space.
• The authors' conclusion: The authors concluded that this case shows a rare alveolar-filling growth pattern of sarcomatoid malignant pleural mesothelioma does exist, even though the pattern is not described in the current WHO classification.

Topics

Medical terms in this study, explained in our Lexicon: Sarcomatoid, Pleural Mesothelioma, Pleural Effusion, Parietal Pleura, Biopsy, Pleura, Pneumonectomy, Parenchyma.

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