Metastasis to the breast from an adenocarcinoma of the lung with extensive micropapillary component: a case report and review of the literature

Abstract

Breast metastasis from extra-mammary malignancy is rare. Based on the literature an incidence of 0.4-1.3% is reported. The primary malignancies most commonly metastasizing to the breast are leukemia-lymphoma, and malignant melanoma. We present a case of metastasis to the breast from a pulmonary adenocarcinoma, with extensive micropapillary component, diagnosed concomitantly with the primary tumor. A 73-year-old female presented with dyspnea and dry cough of 4 weeks duration and a massive pleural effusion was found on a chest radiograph. Additionally, on physical examination a poorly defined mass was noted in the upper outer quadrant of the left breast. The patient underwent bronchoscopy, excisional breast biopsy and medical thoracoscopy. By cytology, histology and immunohistochemistry primary lung adenocarcinoma with metastasis to the breast and parietal pleura was diagnosed. Both the primary and metastatic anatomic sites demonstrated histologically extensive micropapillary component, which is recently recognized as an important prognostic factor. The patient received chemotherapy but passed away within 7 months. Accurate differentiation of metastatic from primary carcinoma is of crucial importance because the treatment and prognosis differ significantly.

Figure 1

Imaging techniques. a) Chest x-ray: Massive pleural effusion occupying most of the left hemithorax with evident displacement of the mediastinum to the right (blue arrow). b) Chest computed tomography: The left lung is atelectatic and compressed by massive pleural effusion (red arrow). The mediastinum and the trachea are severely displaced to the right. A few lymph nodes can be seen, deeply in the left axilla. Additionally, some paratracheal lymph nodes can be observed (yellow arrow). c) Chest computed tomography: A 3,5 × 4,5 cm peripheral lesion, on the left upper lobe, with relative abnormal contour and extension into the surrounding parenchyma. The tumor is in contact to the splanchnic pleura and approached the parietal pleura, possibly invading it (green arrow). d) Digital mammography: Diffuse asymmetrical density in the subalveolar region and the upper outer quadrant of the left breast.

Figure 2

Pleural effusion aspiration smears. a) Clusters of malignant cells with morphological features of adenocarcinoma (Papanicolaou stain, ×400). b) Clusters of malignant cells with morphological features of adenocarcinoma (Papanicolaou stain, ×600). c) Immunocytochemical positivity to TTF-1 (×350). d) Immunocytochemical positivity to TTF-1 (×280).

Figure 3

Bronchoscopy biopsy. Low differentiated adenocarcinoma with micropapillary component (arrow). (Hematoxylin-eosin, ×100).

Figure 4

Parietal pleural biopsy. a) Infiltration by adenocarcinoma with micropapillary pattern (single arrow). Multiple psammoma bodies are observed (double arrow). (Hematoxylin-eosin, ×100). b) Infiltration by adenocarcinoma with micropapillary pattern. (Hematoxylin-eosin, ×400). c) Immunohistochemical nuclear TTF-1 positivity of malignant cells. (×400). d) Immunohistochemical cytoplasmic SP-A positivity of malignant cells. (×400).

Figure 5

Breast biopsy. a) Nodular infiltration by solid (high grade) adenocarcinoma. (Hematoxylin-eosin, ×400). b) Lymphatic tumor emboli of micropapillary pattern adenocarcinoma (single arrow) and multiple psammoma bodies (double arrow). Ectatic duct is noted in the left side. (Hematoxylin-eosin, ×100). c) Immunohistochemical nuclear TTF-1 positivity of adenocarcinoma with solid and micropapillary component. (×100). d) Immunohistochemical nuclear TTF-1 positivity of micropapillary component. (×400).