Primary Peritoneal Low-grade Serous Carcinoma in a Patient With Lynch Syndrome: A Case Report.

Abstract

Lynch syndrome (LS) is an autosomal dominant disease caused by a germline mutation in DNA mismatch repair genes which increases the risk of several cancers such as endometrial and colorectal cancers. However, there are only a few reports of peritoneal malignancies in patients with LS. Herein, we report the first case of a primary peritoneal low-grade serous carcinoma in a woman with LS and provide a literature review of peritoneal malignancies in patients with LS. The patient was a 72-yr-old gravid 2 para 2 Japanese woman with a germline mutation in MLH1. She had a history of colon cancer and endometrial cancer and was treated with total hysterectomy and bilateral salpingo-oophorectomy 14 yr ago. During the follow-up, peritoneal nodules were detected by abdominal computed tomography which were surgically resected. Pathologic examination revealed a low-grade serous carcinoma with cells positive for BerEP4, MOC31, CEA, and WT-1 and negative for BAP1, PAX8, MLH1, and PMS2, by immunohistochemistry. This case report and literature review show that peritoneal low-grade serous carcinoma can occur in patients with LS and that LS-related cancers usually precede primary peritoneal malignancies. The differential diagnosis for peritoneal nodules in patients with LS should, therefore, include peritoneal serous carcinoma and malignant mesothelioma besides metastasis of LS-related cancers. Considering the ambiguous immunophenotypes, a combination of immunohistologic markers would be useful for an accurate diagnosis of such cases.

• Authors: Satomi Makiuchi, Hiroshi Yoshida, Mitsuya Ishikawa, Naoki Kojima, Yae Kanai, Tomoyasu Kato
• Journal: International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists (Int J Gynecol Pathol) Vol. 39 Issue 4 Pg. 327-332 (Jul 2020) ISSN: 1538-7151 [Electronic] United States
• PMID: 31274699 (Publication Type: Case Reports, Journal Article, Review)

Chemical References

• MLH1 protein, human
• MutL Protein Homolog 1

Topics

• Aged
• Carcinoma (complications, diagnosis, genetics, pathology)
• Colonic Neoplasms (surgery)
• Colorectal Neoplasms, Hereditary Nonpolyposis (complications, pathology)
• Diagnosis, Differential
• Endometrial Neoplasms (surgery)
• Female
• Germ-Line Mutation
• Humans
• Hysterectomy
• Immunohistochemistry
• Immunophenotyping
• MutL Protein Homolog 1 (genetics)
• Neoplasms
• Peritoneal Neoplasms (complications, diagnosis, genetics, pathology)
• Salpingo-oophorectomy