Sarcomatoid pleural mesothelioma with osteosarcomatous, chondrosarcomatous and rhabdomyoblastic elements: an extremely rare autopsy case

Our plain-English summary of Sarcomatoid pleural mesothelioma with osteosarcomatous, chondrosarcomatous and rhabdomyoblastic elements: an extremely rare autopsy case, by Y. Tsukamoto, H. Hao, N. Kajimoto, et al (Pathology International, 2015).

The study

• Authors: Y. Tsukamoto, H. Hao, N. Kajimoto, A. Katayama, C. Suzuki, T. Terada, T. Nakano, K. Hanaoka, S. Hirota
• Journal: Pathology International
• Published: 2015;65(1):51-3
• Type of article: Case report, Letter
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This letter to the editor was a case report about one patient: a 70-year-old Japanese man with a smoking history and past asbestos exposure as a machinist for 12 years. The patient had shortness of breath on exertion and right chest pain. Scans showed fluid around the right lung and a heavily calcified mass encasing the right parietal pleura. A first pleural biopsy was diagnosed as extraskeletal osteosarcoma, a bone-forming sarcoma. Blood alkaline phosphatase was raised, peaking at 739 U/L. Chemotherapy with carboplatin and pemetrexed was stopped after two cycles, and the patient died 5 months after symptoms began. At autopsy of the chest organs, the tumor spread along the right pleura without epithelioid cells. Its spindle cells showed focal keratin staining, and 87% had homozygous deletion (loss of both copies) of p16/CDKN2A, which the authors said indicated malignancy. The tumor contained bone-forming, cartilage-forming and rhabdomyoblastic (muscle-like) elements, and had spread to the left lung and left pleura. The authors diagnosed sarcomatoid pleural mesothelioma with heterologous elements. They described it, to their knowledge, as only the second reported case with all three elements.

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 autopsy case, published as a letter to the editor)
• Who was studied: One 70-year-old Japanese man with a smoking history, treated at Hyogo College of Medicine, Japan
• Exposure: Past asbestos exposure as a machinist for 12 years; fiber type not reported
• Main results:
  • Chest X-ray and CT showed right pleural effusion and a right thoracic mass encasing the total right parietal pleura with massive calcification
  • The initial biopsy of the right parietal pleura was diagnosed as extraskeletal osteosarcoma
  • Serum alkaline phosphatase was 542 U/L on admission (normal range 115 to 359 U/L), with a later peak of 739 U/L
  • Cytology of the right pleural effusion showed no malignant cells
  • The patient died 5 months after symptom onset, after two cycles of carboplatin and pemetrexed were stopped
  • At autopsy, no epithelioid cells were found in the tumor
  • The sarcomatous cells along the right parietal pleura showed focal expression of pankeratin
  • Homozygous deletion of p16/CDKN2A was found in 87% of the tumor's spindle cells, which the authors said indicated the cells were malignant
  • Rhabdomyoblastic cells in a restricted area of the tumor were positive for desmin. Osteosarcomatous and chondrosarcomatous differentiation was also present
  • A nodule of malignant spindle cells in the left lung was consistent with metastatic sarcomatoid mesothelioma, and nodules on the left parietal pleura were consistent with contralateral pleural dissemination
• The authors' conclusion: The authors diagnosed sarcomatoid pleural mesothelioma with heterologous elements. They considered it, to their knowledge, only the second reported case with osteosarcomatous, chondrosarcomatous and rhabdomyosarcomatous elements

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Sarcomatoid, Pleural Mesothelioma, Autopsy.

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