Metastasis of Sarcomatoid Malignant Mesothelioma With p16/CDKN2A Deletion Manifested as a Subcutaneous Mass in the Back: A Case Report and Review of Literature

Our plain-English summary of Metastasis of Sarcomatoid Malignant Mesothelioma With p16/CDKN2A Deletion Manifested as a Subcutaneous Mass in the Back: A Case Report and Review of Literature, by K.B. Chen, Y.J. Huang, Y. Huang, et al (International Journal of Surgical Pathology, 2021).

The study

• Authors: K.B. Chen, Y.J. Huang, Y. Huang, Z.W. Wu, X.L. Jin, H. Zhang, X.P. Xiang, L. Chen, L. Chen
• Journal: International Journal of Surgical Pathology
• Published: 2021;29(8):856-863
• Type of article: Case report, Review
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Sarcomatoid malignant mesothelioma (MM) is a rare and aggressive disease, and its diagnosis is challenging. A 60-year-old man presented with a recurrent subcutaneous mass in his right back after the initial resection. A chest computed tomography (CT) scan found right pleural thickening, nodular pleural thickening, pleural effusion, mediastinal, and right infraclavicular lymph nodes enlargement, which indicated a right pleura MM. Immunohistochemical stains of the resected mass showed sarcomatous atypical spindle cells, which were positive for pan-CKs (clone Anti-cytokeratin cocktail AE1/AE3), cytokeratin 5/6 (CK5/6), Wilm's tumor 1, podoplanin, vimentin and programmed death-ligand 1 (PD-L1), and negative for Napsin A, thyroid transcription factor 1, CDX 2, calretinin and desmin, and fluorescent in situ hybridization detected homozygous p16/cyclin-dependent kinase inhibitor 2A (p16/CDKN2A) deletion. The association of the chest CT features and the pathological assessment confirmed metastatic MM in the subcutaneous layer of the back. Moreover, positron emission tomography-CT showed multiple metastases in his brain. He developed massive right pleural effusion and chest tightness soon, and the mass kept growing despite local and systemic treatments. The patient die of pulmonary failure in 3 months.

In plain English

This article reports one patient, a 60-year-old man, described by doctors at a hospital in Hangzhou, China, and reviews earlier published case reports. It does not say whether he had been exposed to asbestos. He had a growing lump under the skin of his right back. It was removed but came back within 2 weeks. Scans showed thickening and fluid in the lining of the right lung (the pleura) and enlarged lymph nodes. Stains of the back lump, plus a genetic test on cell samples showing loss of the p16/CDKN2A gene, supported a diagnosis of sarcomatoid malignant mesothelioma of the right pleura that had spread under the skin. A PET-CT scan also showed several areas of spread in the brain. He received chemotherapy, radiation, focused ultrasound, immunotherapy and fluid drainage, but the back tumor kept growing. He died of pulmonary failure within 3 months of diagnosis. The authors found 18 earlier reports of skin or under-skin spread from mesothelioma, only 3 of them sarcomatoid. The authors concluded that the diagnosis could be made from the metastatic lump rather than limited lung biopsy tissue.

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 of a single patient with a review of previously published case reports
• Who was studied: one 60-year-old man with a growing subcutaneous mass in the right back; authors based at the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China; dates not given
• Exposure: Not reported: the article does not describe any asbestos or occupational exposure for this patient
• Main results:
  • Ultrasound showed a large tumor with bleeding in the muscle layer of the back, measuring 13.8 × 4.7 cm
  • After surgical removal, the mass came back within 2 weeks
  • Chest CT showed right pleural thickening, nodular pleural thickening, pleural effusion, and enlarged mediastinal and right infraclavicular lymph nodes
  • The tumor cells stained positive for mesothelial and other markers (pan-CKs, CK5/6, WT1, podoplanin, vimentin, PD-L1); calretinin was not expressed
  • Ki-67 index was 80% and PD-L1 tumor proportion score was 90%
  • FISH on cytology specimens showed homozygous p16/CDKN2A deletion
  • PET-CT showed multiple brain metastases; the right lung nodule had an SUVmax of 19.0
  • About 2000 mL of bloody pleural fluid was drained from the chest
  • After treatment, the mediastinal and right infraclavicular lymph nodes shrank, but the tumor in the back grew significantly
  • The patient died within 3 months of initial diagnosis
  • Literature review: the authors found 18 earlier case reports of cutaneous or subcutaneous metastases from mesothelioma, only 3 of the sarcomatoid type
  • Among those 18 reports, the masses were the first sign or were seen at initial diagnosis in 10 cases, and appeared after diagnosis of pleural mesothelioma in 6 cases; the 1-year survival rate was 20%
• The authors' conclusion: The authors concluded that they reported an extremely rare case of subcutaneous metastasis from right pleural sarcomatoid mesothelioma. They made the diagnosis by histological and molecular analysis of the subcutaneous lesion rather than limited lung biopsy tissue, and found PET-CT useful for identifying metastases outside the chest.
• Limitations the authors state:
  • The effectiveness of intrapleural cisplatin could not be judged because follow-up was too short

Topics

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

Medical terms in this study, explained in our Lexicon: Metastasis, Sarcomatoid, Malignant Mesothelioma, CDKN2A, Pleural Thickening, Pleural Effusion, Pleura, Spindle Cell.

Related studies

• Fluorescence in situ hybridization (FISH) provides estimates of minute and interstitial BAP1, CDKN2A, and NF2 gene deletions in peritoneal mesothelioma — S. Brich, F. Bozzi, et al. (2020)
• p16 Deletion in sarcomatoid tumors of the lung and pleura — N. Tochigi, R. Attanoos, et al. (2013)
• Sarcomatoid Mesothelioma: A CDKN2A molecular analysis of 53 cases with immunohistochemical correlation with BAP1 — M. Zaleski, N. Kalhor, et al. (2020)
• CDKN2A and BAP1 germline mutations predispose to melanoma and mesothelioma — M. Betti, A. Aspesi, et al. (2016)
• Malignant mesothelioma in situ diagnosed by methylthioadenosine phosphorylase loss and homozygous deletion of CDKN2A: a case report — K. Minami, N. Jimbo, et al. (2020)
• Subcutaneous seeding after ultrasound-guided placement of intrapleural catheter. An unusual complication of the intracavitary palliative treatment of pleural mesothelioma — S. Sartori, I. Nielsen, et al. (1999)

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