Malignant Peritoneal Mesothelioma in an Adolescent Male With BAP1 Deletion

Our plain-English summary of Malignant Peritoneal Mesothelioma in an Adolescent Male With BAP1 Deletion, by S. Taylor, D. Carpentieri, J. Williams, et al (Journal of Pediatric Hematology/oncology, 2015).

The study

• Authors: S. Taylor, D. Carpentieri, J. Williams, J. Acosta, R. Southard
• Journal: Journal of Pediatric Hematology/oncology
• Published: 2015;37(5):e323-7
• Type of article: Case report
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Diffuse malignant peritoneal mesotheliomas in children are uncommon, aggressive tumors with a grave prognosis. We herein report the clinical, radiologic, and pathologic findings of a 16-year-old male. The adolescent presented with a history of abdominal pain, nausea and daily, nonbilious, nonbloody emesis for 3 weeks. Radiographic imaging suggested small bowel obstruction. The diagnostic work-up and differential diagnoses are discussed. Histologically, the tumor was composed of epithelioid cells with a papillary and glandular architectural pattern. A few glands appeared to produce mucinous material. Histochemistry revealed PAS diastase resistant mucin, an inconspicuous finding in diffuse malignant peritoneal mesothelioma. An extensive immunohistochemistry panel (calretinin, WT-1, D2-40, CK 7, CAM 5.2, CK 5/6, CEA, B72.3, CK 20, CD10, CD30, CD15, CD117, PLAP, S100, TFE3, and EMA) confirmed the diagnosis. Of special interest, BAP1 staining was cytoplasmic and consistent with 3p deletion detected by conventional cytogenetics. The ultrastructural analysis demonstrated long microvilli, desmosomes, and intercellular junctions which further supported the diagnosis.

In plain English

This case report described a 16-year-old Hispanic male at Phoenix Children's Hospital who had diffuse malignant peritoneal mesothelioma, a cancer of the abdominal lining. He came in with three weeks of abdominal pain, nausea and vomiting, and scans showed a small bowel obstruction. No known direct or indirect exposure to asbestos was found, and his family history was limited because of social factors. Surgery found enlarged nodules in the mesentery, and a 12 cm section of small bowel was removed. Tissue tests and electron microscopy supported the epithelial subtype. The tumor produced mucin, which the authors described as, to their knowledge, only the third reported case of this kind. Staining showed no BAP1 protein in the cell nuclei, matching a deletion on chromosome 3p. No inherited BAP1 mutation was found in his blood, indicating a change only in the tumor cells. The authors called this the first reported BAP1 deletion in a child with this disease. He received six cycles of cisplatin and pemetrexed and was free of disease 27 months after diagnosis. The authors concluded the deletion may be implicated in this tumor's disease process.

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 16-year-old Hispanic male with diffuse malignant peritoneal mesothelioma, Phoenix Children's Hospital, Phoenix, AZ
• Exposure: No known direct or indirect asbestos exposure was found in this patient. The study focused on a BAP1 gene abnormality (chromosome 3p deletion) in the tumor.
• Main results:
  • Electron microscopy findings supported a diagnosis of diffuse malignant peritoneal mesothelioma, epithelial subtype, in this patient
  • The patient's tumor contained mucin that stained positive with PAS with and without diastase. The authors described it as, to their knowledge, only the third reported case of this kind.
  • BAP1 staining of the patient's tumor showed no nuclear expression, with only weak or focal staining in the cytoplasm
  • Cytogenetic analysis of the tumor showed a deletion of chromosome 3p, consistent with the BAP1 staining
  • No BAP1 germline mutation was found in the patient's blood, indicating the change was confined to the tumor cells (somatic)
  • The tumor was near tetraploid, with 82 to 87 chromosomes, and had structural abnormalities in chromosomes 1q, 3p, 6, 9q and 22
  • The authors stated this was, to their knowledge, the first reported case of a BAP1 deletion in a pediatric patient with diffuse malignant peritoneal mesothelioma
  • The patient received cisplatin and pemetrexed every 3 weeks for 6 cycles
  • The patient was free of disease 27 months after initial diagnosis
• The authors' conclusion: The authors concluded that the 3p deletion involving the BAP1 gene in this patient's tumor may be implicated in the tumor's pathophysiology
• Limitations the authors state:
  • The patient's family medical history information was limited due to social factors

Topics

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

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, BAP1, Prognosis, Epithelioid, Immunohistochemistry, Calretinin, Wilms Tumor 1 (WT-1), Podoplanin (D2-40).

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)
• The value of BRCA-1-associated protein 1 expression and cyclin-dependent kinase inhibitor 2A deletion to distinguish peritoneal malignant mesothelioma from peritoneal location of carcinoma in effusion cytology specimens — W. Althakfi, S. Gazzo, et al. (2020)
• BAP1 Is Altered by Copy Number Loss, Mutation, and/or Loss of Protein Expression in More Than 70% of Malignant Peritoneal Mesotheliomas — N. Leblay, F. Leprêtre, et al. (2017)
• Loss of BAP1 expression is very rare in peritoneal and gynecologic serous adenocarcinomas and can be useful in the differential diagnosis with abdominal mesothelioma — J. Andrici, J. Jung, et al. (2016)
• A Tumor-Specific Neo-Antigen Caused by a Frameshift Mutation in BAP1 Is a Potential Personalized Biomarker in Malignant Peritoneal Mesothelioma — J. Lai, Z. Zhou, et al. (2016)
• Morphological difference between pleural mesothelioma cells in effusion smears with either BAP1 loss or 9p21 homozygous deletion and reactive mesothelial cells without the gene alterations — S. Matsumoto, M. Hamasaki, et al. (2019)

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