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

Abstract

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.

Keywords: Breast cancer; thymoma.

Figure 1

A medium sized tumor was found in the left mammary gland. After the confirmation of lobular breast carcinoma, a modified radical left mastectomy and a sentinel lymph node biopsy was scheduled. (A,B) Mammography of the left breast revealed a nodular tumor, in the upper outer quadrant of the left breast, 1.5 cm in greater diameter; (C) a modified radical left mastectomy and a sentinel lymph node biopsy was scheduled.

Figure 2

CT scan of the anterior mediastinum revealed a large tumor penetrating the pericardium, a smaller tumor in left parietal pleura and numerous small sized nodules in left lung. (A) In the anterior mediastinum, there is a lobular, partially mineralized tumor 15 cm × 9 cm × 4.5 cm, in contact with the aortic arch, the stem and the branch of the left pulmonary artery and the heart’s left ventricle, penetrating the pericardium; (B) a similar maze 1.8 cm × 1.1 cm is found in the left side of parietal pleura and the left lung has numerous small sized nodules.

Figure 3

Tissue sections of the mediastinal tumor (hematoxylin/eosin stain) present a thymoma consisted of lymphocytes and thymocytes. (A) The mediastinal tumor was a B3 thymoma presented as an organoid nodular lesion, with cystic formations and mineralization, surrounded by thick bundles of collagen (hematoxylin/eosin stain, magnification 25×); (B) the tumor cells are large, with lymphoepithelial morphology and few immature lymphocytes among them. There is mild to moderate cellular atypia and vesicular nuclei with prominent nucleoli and few mitoses. There was no evidence of keratinization (hematoxylin/eosin stain, magnification = scale bar).

Figure 4

Immunohistochemical analysis confirmed the diagnosis of B3 thymoma. (A) CK19 positive in neoplastic lymphoepithelial cells; (B) CK5/6 also positive in tumor cells; (C) CD5 positive intraepithelial lymphocytes; (D) NK lymphocytes among tumor cells stain positive for CD57.

Figure 5

Lobular breast cancer (hematoxylin/eosin stain) is negative for e-cadherin but strongly positive for estrogen and progesterone receptors. (A) The breast tumor was a classic lobular carcinoma, consisted of monotonous small to medium sized neoplastic epithelial cells, arranged in cords or small aggregates of intermediate malignancy, grade II (hematoxylin/eosin stain); (B) e-cadherin immunostain (a marker for ductal breast carcinoma) was negative in our case; (C) the tumor cells were positive for estrogen receptor (Allred score: 8); (D) for progesterone receptor (Allred score: 7).

Figure 6

The patient underwent a median sternotomy, followed by a left intrapericardial pneumonectomy, without extracorporeal circulation. (A) Left lung pneumonectomy via medium sternotomy, including pericardial excision; (B) reconstruction of the pericardium’s left part with synthetic mesh.