PMC9287469_01
Preoperative imaging findings. (A) Computed tomography scan showing a 1.8 cm solitary solid pulmonary nodule in the left upper lobe of the lung. (B) Positron emission tomography-computed tomography. A high fluorodeoxyglucose uptake with a maximum standardized uptake value of 11.5 was revealed.
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However, during her follow-up two years after mastectomy, the CT scan at our hospital revealed a solitary 1.8 cm solid pulmonary nodule in the upper left lobe (Fig. 1A). Positron emission tomography-CT showed increased fluorodeoxyglucose uptake with a maximum standardized uptake value of 11.5 (Fig. 1B).
Pathological findings. (A) The low-power view of the pulmonary nodule shows that the tumor comprised a necrotic center (hematoxylin-eosin staining). (B) The high-power view of the pulmonary nodule. Sheets of small round cells had prominent nuclear chromatin with molding and palisading formation (hematoxylin-eosin staining). (C) The low-power view of the initial breast cancer. Prominent central necrosis adjacent to the periphery of viable tumor, resembling a pulmonary nodule (hematoxylin-eosin staining). (D) The high-power view of the initial breast cancer. Sheets of small round cells were present with chondromyxoid matrix in the central necrotic area (E), indicating MPC of the breast (hematoxylin-eosin staining). (F) The high-power view of the pulmonary nodule. Focal chondromyxoid-like matrix is seen, indicating metastasis from MPC (hematoxylin-eosin staining).. MPC: matrix-producing carcinoma.
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These findings suggested poorly differentiated carcinoma (Fig. 2A and B). SCLC (Fig. 2A and B). Surgical specimen of the primary breast carcinoma was collected and reviewed. Microscopically, the breast cancer consisted of sheets of small round cells with a high nuclear/cytoplasmic ratio and a focal chondromyxoid matrix in the central necrotic area, indicating MPC (Fig. 2C-E). Hence, we arrived at the diagnosis of pulmonary metastasis of MPC (Fig. 2F).