[274] Characteristics of Breast Cancer in Patients with PTEN Hamartoma Tumour Syndrome

Andrew P Sciallis, Aziza Nassar, Lisa A Boardman, Vishal S Chandan, Sejal S Shah. Mayo Clinic, Rochester, MN

Background: Phosphatase and tensin homologue (PTEN) is a tumor suppressor protein important to the (PI3K)-AKT pathway of tumor cell growth and survival. Germline mutations of PTEN causing haploinsufficiency are central to the PTEN hamartoma tumour syndrome, of which Cowden and Bannayan-Riley-Ruvalcaba (BRR) syndromes are members. Cowden syndrome (CS) is also a hereditary breast cancer syndrome, and it is well-known that affected patients have an increased lifetime risk of developing breast cancer. However, analysis of specific tumor characteristics, including type, grade, hormone receptor status, and stage at presentation, has been subject to only a few published studies. Our institution has a well-characterized database of patients affected with a PTEN hamartoma tumor syndrome. We wish to present our experience with these patients focusing on breast cancer characteristics.
Design: After obtaining IRB approval, we accessed a departmental database of patients with either Cowden or Bannayan-Riley-Ruvalcaba syndromes. Syndrome diagnosis was reached through established clinical criteria with occasional supplementation through PTEN gene mutation analysis. Patient characteristics were then reviewed.
Results: The study population consisted of 20 patients (10 M, 10 F; average age 53.6 years), 17 with CS and 3 with BRR. Breast cancer was present in 6 CS patients (all female; 60% of women; average age at presentation 44.8 years). Benign breast disease, typically manifested as proliferative fibrocystic changes, affected 3 additional women, 2 of whom required bilateral mastectomy due to symptom severity. In breast cancer patients, 3 tumors were invasive vs 3 in situ, 3 patients had bilateral disease, and all were ductal phenotype of various grade. Patients with invasive disease presented with a breast mass (average size 2.1 cm, range 1.2-3.5) and had either Stage IIA (2) or Stage IIIA (1) disease. In 2 patients (1 bilateral invasive tumors; 1 DCIS) immunohistochemistry was performed and all were ER/PR positive but did not overexpress HER2 if invasive.
Conclusions: Our analysis demonstrates the high rate of breast cancer occurring in women with CS. Breast cancer was manifested as either invasive or in situ disease; all tumors were ductal and expressed ER and PR when performed. Our study highlights the phenotypic tumor similarities between CS patients and the general population, and especially given the absence of breast cancer in affected males, may suggest a potential interaction between tumor development in CS patients and hormone status.
Category: Breast

Monday, March 4, 2013 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 37, Monday Morning


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