Metastatic Malignant Peritoneal Mesothelioma Mimicking an Autoinflammatory Syndrome in a 12-Year-Old Boy

Our plain-English summary of Metastatic Malignant Peritoneal Mesothelioma Mimicking an Autoinflammatory Syndrome in a 12-Year-Old Boy, by G. Olmedilla, C. Undaondo, W. Vasquez, et al (Pediatric and Developmental Pathology, 2021).

The study

• Authors: G. Olmedilla, C. Undaondo, W. Vasquez, N. Rodriguez
• Journal: Pediatric and Developmental Pathology
• Published: 2021;24(5):478-483
• Type of article: Case report
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A case of a malignant peritoneal mesothelioma mimicking an autoinflammatory syndrome in a 12-year-old boy is reported. The patient initially presented with lymphadenopathy and weight loss but without abdominal pain. Three things confounded the initial diagnosis: a positive test result for a gene related to cryopyrin-associated periodic syndrome, a positive response to the autoinflammatory syndrome treatment, and a lymph node biopsy which showed "hyperplastic mesothelial cells in the lymph sinuses." His symptoms relapsed several years later, and a peritoneal biopsy confirmed the final diagnosis. Complete morphological, immunohistochemical, and molecular diagnoses are described. A translocation in the TERT gene involving the truncation of the promoter was found in the mesothelioma. The translocation has never been described in mesotheliomas and is of an unknown significance.

In plain English

This case report described a 12-year-old boy with malignant peritoneal mesothelioma (a cancer of the abdominal lining) that first looked like an autoinflammatory syndrome. He had fevers, tiredness, weight loss and an enlarged lymph node above the left collarbone, but no abdominal pain. A lymph node biopsy was read as overgrown but non-cancerous mesothelial cells. A genetic test found an NLRP3 gene mutation compatible with cryopyrin-associated periodic syndrome (CAPS). He improved on corticosteroids and later on tocilizumab, and stayed symptom-free for 5 years. When symptoms returned, a biopsy of the omentum (fatty abdominal tissue) showed tumor invading fat. The final diagnosis was epithelioid malignant peritoneal mesothelioma that had spread to lymph nodes. Asbestos exposure was not documented in the boy or his direct relatives. Tumor testing found a TERT gene rearrangement, which the authors said had never been described in mesothelioma and was of unknown significance. He had surgery and chemotherapy; 36 months after surgery he was still receiving maintenance pemetrexed, and the lymph node tumor had stabilized. The authors concluded the mesothelioma mimicked an autoinflammatory syndrome from the start.

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
• Who was studied: One 12-year-old boy, followed over about 8 years. The authors are from hospitals in Madrid, Spain. His cytoreductive surgery was done at another institution.
• Exposure: No asbestos exposure was documented in the patient or his direct relatives.
• Main results:
  • The first lymph node biopsy showed mesothelial-appearing cells in the lymph node sinuses. Doctors interpreted this as an inflammatory reaction rather than cancer.
  • Genetic testing found a heterozygous V-198-M mutation in the NLRP3 gene, which was compatible with cryopyrin-associated periodic syndrome (CAPS).
  • Anakinra gave no improvement. Intravenous tocilizumab gave a complete response, and the patient stayed free of symptoms for 5 years.
  • After relapse, a biopsy of the omentum showed tumor infiltrating fat tissue. The final diagnosis was peritoneal malignant epithelioid-type mesothelioma with lymph node metastasis.
  • Tumor cells retained BAP-1 expression, and no fusions affecting the EWSR1 or FUS genes were found.
  • A rearrangement involving the TERT gene, translocation t(4;5)(p13;p15.33), was found in both the peritoneal tumor and the second lymph node biopsy. It was present only in the tumor tissue (somatic).
  • He was treated with cytoreductive surgery plus heated intraoperative chemotherapy (cisplatin and adriamycin), followed by 8 cycles of cisplatin-pemetrexed with partial response. At 36 months after surgery he was still on pemetrexed maintenance treatment, and the tumor had stabilized in lymph nodes above and below the diaphragm.
• The authors' conclusion: The authors believed this was a malignant metastatic peritoneal mesothelioma that mimicked an autoinflammatory syndrome from the beginning of the disease. They stated that the TERT translocation had never been described in mesotheliomas and was of unknown significance.
• Limitations the authors state:
  • The TERT translocation could not be confirmed in the first lymph node biopsy because the DNA in that tissue had degraded.

Topics

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

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Lymphadenopathy, Biopsy, Mesothelial Cells, Translocation, Mesothelioma.

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