Jejunal Metastasis from Malignant Pleural Mesothelioma during Long-Term Nivolumab Therapy: A Case Report and Literature Review

Our plain-English summary of Jejunal Metastasis from Malignant Pleural Mesothelioma during Long-Term Nivolumab Therapy: A Case Report and Literature Review, by H. Minagi, H. Aoki, M. Nosaka, et al (Surgical Case Reports, 2026).

The study

• Authors: H. Minagi, H. Aoki, M. Nosaka, T. Ogawa, M. Watanabe, T. Arata, K. Katsuda, K. Tanakaya
• Journal: Surgical Case Reports
• Published: 2026;12(1)
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

Introduction: Gastrointestinal metastasis from malignant pleural mesothelioma (MPM) is exceedingly rare and lacks a standardized diagnostic work-up.

Case Presentation: An 87-year-old man with asbestos exposure and a 5-year history of left-sided MPM, radiographically stable on long-term nivolumab therapy, presented with melena and anemia. Contrast-enhanced CT revealed a circumferential jejunal lesion near the duodenojejunal flexure with enlarged mesenteric nodes. Double-balloon enteroscopy confirmed a 40-mm obstructive tumor, but biopsies were non-diagnostic. Partial jejunectomy with targeted mesenteric lymph-node dissection was performed. Histology with a mesothelioma-oriented immunohistochemical panel-negative for CEA and BerEP4 and positive for broad-spectrum cytokeratins-supported a diagnosis of metastatic MPM; nodal metastases were present. Given his age, no further systemic therapy was administered; the patient died 20 months postoperatively from progression of MPM.

Conclusions: In MPM receiving immune-checkpoint inhibitor therapy, unexplained gastrointestinal bleeding should prompt comprehensive gastrointestinal evaluation, including small-bowel assessment. Surgery can secure symptom relief and a definitive diagnosis.

© 2026 The Author(s). Published by Japan Surgical Society.

In plain English

This article described one patient and briefly reviewed earlier published cases. The patient was an 87-year-old former seaman with occupational asbestos exposure who had been diagnosed with left-sided malignant pleural mesothelioma five years earlier. After several chemotherapy regimens, the patient received nivolumab, an immune-checkpoint inhibitor drug, for 40 cycles over 21 months. During that time the pleural disease stayed stable on scans. The patient then developed melena (dark stools from bleeding), abdominal discomfort and anemia. Scans and enteroscopy found a 40-mm, nearly obstructing tumor in the jejunum, part of the small bowel. Biopsies did not give a diagnosis. Surgeons removed part of the jejunum and nearby lymph nodes. Tissue stains favored mesothelioma that had spread to the jejunum and lymph nodes. Some markers were equivocal and certain confirmatory tests were not done, so the authors said some diagnostic uncertainty remained. The patient died 20 months after surgery from mesothelioma progression. A PubMed search found nine such cases, including this one. At 60 months after diagnosis, this case had the longest reported interval. The authors concluded that unexplained abdominal pain or gastrointestinal bleeding in such patients on immune-checkpoint therapy should prompt full gastrointestinal evaluation, including the small bowel.

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 one patient, with a literature review of published cases of small-bowel metastasis from malignant pleural mesothelioma
• Who was studied: One 87-year-old man, a former seaman, with left-sided malignant pleural mesothelioma diagnosed 5 years earlier. The literature review covered nine cases in total, including this one, found by an English-language PubMed search through December 31, 2024.
• Exposure: Occupational asbestos exposure as a former seaman. No fiber type was given. The patient's treatment included cisplatin–pemetrexed, carboplatin–pemetrexed and gemcitabine, followed by nivolumab for 40 cycles over 21 months.
• Main results:
  • During nivolumab therapy, the pleural mesothelioma remained stable on imaging. Nivolumab was given for 40 cycles over 21 months.
  • Double-balloon enteroscopy found a 40-mm, circumferential, near-obstructive jejunal lesion.
  • Endoscopic biopsies of the jejunal tumor did not give a diagnosis.
  • Serum hyaluronic acid was raised in this patient: 115 ng/mL, against a reference of less than 50 ng/mL.
  • In the resected tumor, staining was negative for the epithelial markers CEA and BerEP4 and negative for D2-40. Calretinin and WT-1 staining was only equivocal.
  • The overall findings favored jejunal metastasis from mesothelioma, with metastases in the mesenteric lymph nodes.
  • The immunophenotype of the jejunal lesion differed from that of the primary pleural tumor.
  • After surgery, the patient developed ileus on postoperative day 9, which resolved with conservative management.
  • The patient received no further systemic therapy and died 20 months after surgery from progression of mesothelioma.
  • Across the nine reported cases, the median interval from mesothelioma diagnosis to small-bowel metastasis was 9 months.
  • This case occurred at 60 months, the longest interval reported.
  • All patients in the nine reported cases were male.
  • Lymph-node metastases were documented in three of the nine reported cases, including this one.
• The authors' conclusion: The authors concluded that in mesothelioma patients receiving immune-checkpoint inhibitor therapy, unexplained abdominal pain or gastrointestinal bleeding should prompt comprehensive gastrointestinal evaluation, including the small bowel. They also concluded that resecting a resectable lesion provides symptom control and a definitive diagnosis.
• Limitations the authors state:
  • Calretinin and WT-1 staining was equivocal, which limits how certain the pathologic diagnosis is.
  • BAP1/MTAP immunostaining and p16 FISH were not performed because of limited availability at the institution, so a degree of diagnostic uncertainty remains.
  • The authors stated that it cannot be established whether immune-checkpoint inhibitor treatment caused the long interval before metastasis.

Topics

Medical terms in this study, explained in our Lexicon: Metastasis, Pleural Mesothelioma, Nivolumab (Opdivo), Asbestos Exposure, Histology, Mesothelioma, Broad-spectrum Cytokeratin, Systemic Therapy.

Related studies

• Small bowel metastasis from pancreatic cancer in a long-term survival patient with synchronous advanced malignant pleural mesothelioma: A case report and literature review — M. Fasano, C.M. Della Corte, et al. (2016)
• Response to Nivolumab followed by complete cytoreductive surgery with HIPEC resulted in long-term survival in a patient with sarcomatoid-predominant biphasic peritoneal mesothelioma. A case report — P.H. Sugarbaker (2023)
• Long-Term Disease Control With Second-Line Nivolumab Monotherapy in Malignant Pleural Mesothelioma: A Case Report — S. Otsuka, K. Hiraoka, et al. (2026)
• Sarcomatoid diffuse pleural mesothelioma in an 80-year-Old woman with long-term response to nivolumab plus ipilimumab: A case report — Y. Yoshida, H. Mizugaki, et al. (2025)
• Tract metastasis in patients with long-term pleural catheter-computed tomography diagnosis and longitudinal assessment — F. Hamad, C. Souza, et al. (2021)
• Jejunal Perforation by Metastasis of Malignant Pleural Mesothelioma — M.I. Navarro García, A. Sánchez Pérez, et al. (2015)

Browse more research in Surgical Case Reports, or return to medical research.