Does familial breast cancer and thymoma suggest a cancer syndrome? A family perspective

Metastatic Thymoma Harboring a Deleterious BRCA2 Mutation Derives Durable Clinical Benefit from Olaparib

Thymomas comprise a group of rare epithelial neoplasms of the anterior mediastinum. Whereas localized disease carries a favorable prognosis, the majority of patients with metastatic thymomas experience progression or recurrence over a 10-year period. Although targeted therapies have become standard of care in many malignancies, no clinically actionable mutations have consistently been identified in metastatic thymomas. Here, we describe a patient with an aggressive thymoma complicated by extensive pleural metastases. Over a 16-year period, she progressed on multiple treatment regimens. To identify additional treatment options, tissue from a pleural metastasis was sent for next-generation sequencing, revealing mutations in BRCA2, tyrosine kinase 2, and SET domain containing 2. Based on supporting evidence for poly (ADP-ribose) polymerase (PARP) inhibition in other BRCA-mutated tumors, the patient was started on the PARP inhibitor olaparib. She derived significant clinical benefit from treatment, with imaging showing overall stabilization of her disease. Here, we review the genotyping results of her tumor and discuss the functional and clinical significance of the mutations in her cancer as well as implications for managing patients with advanced BRCA-mutant thymomas. KEY POINTS: Targeted therapy has yet to enter the standard clinical management of metastatic thymomas. Patients with BRCA2-mutant thymomas may benefit from poly (ADP-ribose) polymerase inhibition.

Coincidence of thymoma and breast cancer and in a 56-year-old female patient

We present a case of a 56-year-old female, with a familial history of breast, lung and brain cancer, which revealed a breast tumor, located in the upper outer quadrant of the left breast. During the routinely staging examinations, a 15 cm intrathoracic tumor was found in the upper left mediastinum, penetrating the pericardium and a smaller tumor, in the left side of parietal pleura. Core biopsies from both lesions, revealed a lobular carcinoma of the breast classic type, grade II (e-cadherin-, ER+, PR+, Her-2-, Ki-67 10%) and a B3 thymoma (CK19+, CD5+) penetrating the pericardium and the left lung. A synchronous removal of both tumors was scheduled, including median sternotomy and left intrapericardial pneumonectomy, followed by a modified radical left mastectomy and a sentinel lymph node biopsy. The postoperative course was uneventful. This case advocates that thymoma patients appear to have a predisposition towards developing additional neoplasms, as breast carcinoma. Clinicians should be aware of the increased incidence of extrathymic cancers, occurring in thymoma patients.