Breast Cancer with a Newly Diagnosed Variant in the Gene: A Case Report.

Introduction: The phosphatase and tensin homolog hamartoma tumor syndrome (PHTS) refers to a spectrum of disorders caused by variants of the phosphatase and tensin homolog () gene, including Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome, adult Lhermitte-Duclos disease, and autism spectrum disorders associated with macrocephaly. PHTS is characterized by hamartomas in multiple organs and is associated with an increased risk of developing malignant tumors including, breast, thyroid, endometrial, colorectal, and kidney tumors. Breast cancer is the most common malignancy associated with PHTS.

Case Presentation: We describe the case of a 44-year-old female patient with invasive ductal carcinoma of the right breast. Cobblestone papillomatosis was present in the gingiva. She had a medical history of bilateral adenomatous goiters for 10 years. Her mother had been diagnosed with breast cancer, thyroid and tongue tumors, gastric polyps, hepatic hemangioma, and collagen disease. Additionally, the patient's maternal grandmother had a history of colon cancer. Based on the patient's family history and physical findings, CS was suspected, and direct DNA sequencing analysis revealed a haplotype c.634del mutation in exon 7 of the gene. Although there is no clear evidence supporting risk-reducing surgery for PHTS, a right nipple-sparing mastectomy, sentinel lymph node biopsy, and tissue expander reconstruction were performed.

Conclusions: We report a case of breast cancer with a newly diagnosed c.634del mutation in the gene. We also reviewed the current literature on genetic variants and breast cancer subtypes.