Malignant STK11 adnexal tumor harboring a somatic mutation in a woman previously diagnosed with mesothelioma, a case report

Our plain-English summary of Malignant STK11 adnexal tumor harboring a somatic mutation in a woman previously diagnosed with mesothelioma, a case report, by C.R. Rutherford, T.A. Rives, D.W. Piecoro, et al (Gynecologic Oncology Reports, 2024).

The study

• Authors: C.R. Rutherford, T.A. Rives, D.W. Piecoro, C.S. Dietrich
• Journal: Gynecologic Oncology Reports
• Published: 2024;56:101521
• Type of article: Case report
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

STK11 germline pathogenic variants are typically associated with Peutz-Jeghers syndrome, an autosomal dominant disease characterized by hamartomatous polyps in the gastrointestinal tract, hyperpigmented patches, and increased risk of stomach, colorectal, small bowel, and breast cancers (Beggs et al., 2010). Mutations in this gene have also been identified in skin, pancreatic, testicular, and stromal ovarian cancer (Fagerberg et al., 2014). To date, there have been less than 30 cases of ovarian cancer reported associated with mutated STK11 (Bennett et al., 2021). In this report, we discuss a rare case of a STK11 adnexal tumor in a 39-year-old woman previously diagnosed with malignant mesothelioma. After 33 months with no evidence of disease following cytoreductive surgery with HIPEC and adjuvant chemotherapy, a new retroperitoneal lesion was noted on imaging. After resection, molecular testing indicated an STK11 mutation, and histology was consistent with an STK11 adnexal tumor. A high index of suspicion is required to make the diagnosis of STK11 adnexal tumor due to its non-distinct pathology and IHC staining. Due to the rarity of this neoplasm, analysis of current and future cases of the STK11 adnexal tumor is necessary to understand its pathogenesis, genetic mutational analysis, clinical course, and best treatment options.

© 2024 The Author(s).

In plain English

This case report, by authors at the University of Kentucky, described one woman, aged 39, whose tumor was first diagnosed as malignant peritoneal mesothelioma. The article does not mention asbestos exposure. Expert review of an omental nodule supported mesothelioma. She was treated with cytoreductive surgery plus heated chemotherapy inside the abdomen (HIPEC) using mitomycin C, followed by 3 cycles of cisplatin and pemetrexed. Tumor testing found mutations in ARID1A, EP300 and STK11. She had no evidence of disease for 33 months. Then a new retroperitoneal nodule was found, and a mass was removed. Its pathology did not favor mesothelioma. Experts favored a rare STK11 adnexal tumor, and the authors judged that the original tumor was likely misclassified. Testing for inherited mutations found no pathogenic germline mutations. After this surgery, a scan showed a liver lesion that MRI suggested could be a metastatic implant. She then received 6 cycles of carboplatin and paclitaxel and had no evidence of disease 4 months after treatment. The authors concluded that, because these tumors resemble mesothelioma, a high level of suspicion is needed for accurate diagnosis, and that platinum-based chemotherapy may be effective.

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 39-year-old woman, reported by authors at the University of Kentucky. Specimens dated 2018 (original tumor) and 2023 (recurrence).
• Main results:
  • The original omental nodule was sent for expert consultation, which supported a diagnosis of malignant peritoneal mesothelioma (MPM).
  • She was treated with cytoreductive surgery with HIPEC using mitomycin C.
  • After surgery she received adjuvant chemotherapy: 3 cycles of cisplatin and pemetrexed.
  • Her gynecologic organs showed no abnormality on final pathology.
  • Sequencing of the original tumor found mutations in ARID1A, EP300 and STK11.
  • She had no evidence of disease for 33 months before a 1.1 cm retroperitoneal nodule was seen on imaging.
  • Sequencing of the recurrent tumor found the same STK11 mutation and an ARID1A deletion, but not the EP300 mutation.
  • A genomic score gave a 96% likelihood of ovarian origin for the recurrent tumor.
  • The recurrence was diagnosed as an STK11 adnexal tumor rather than recurrent MPM, with possible misclassification of the original tumor.
  • Germline (inherited) genetic testing found no pathogenic mutations.
  • After the second surgery, a PET/CT scan showed a liver subcapsular lesion, and follow-up MRI was concerning for a metastatic implant.
  • She then received 6 cycles of carboplatin and paclitaxel.
  • She had no evidence of disease 4 months after her final treatment dose.
• The authors' conclusion: The authors concluded that, because the STK11 adnexal tumor is histologically and immunohistochemically similar to malignant mesothelioma, a high level of suspicion is required for accurate diagnosis, and that platinum-based chemotherapy may be effective.
• Limitations the authors state:
  • Different companies sequenced the original and recurrent tumors, so the two sets of results may not be directly comparable.

Topics

Medical terms in this study, explained in our Lexicon: Somatic Mutation, Mesothelioma, Ovarian Cancer, Cytoreductive Surgery, HIPEC, Chemotherapy, Molecular Profiling, Histology.

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