PMC5925950_01
Computed tomography (CT) scan of the left lung. (a) CT on admission, showing a 20-mm lung tumor in the left lower lobe. (b) The lung tumor had shrunk remarkably after 4 weeks of afatinib treatment. (c) CT scan showed the re-growing lung tumor in the left upper lobe when disease progression was confirmed after afatinib treatment. (d) The lung tumor had shrunk remarkably after 4 cycles of cisplatin and irinotecan treatment.
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Chest computed tomography (CT) revealed a 20-mm solitary tumor in the left upper lobe (Fig. 1a) and single left hilar lymph node enlargement and small bilateral pulmonary nodules. One month later, CT and MRI showed partial remission of pulmonary tumors (Fig. 1b) and disappearance of brain metastases. However, after starting afatinib treatment for 7 months, CT and MRI demonstrated recurrence of the primary tumor in the left upper lobe (Fig. 1c) and multiple brain metastases. After 4 cycles of chemotherapy, the patient showed shrinkage of the lung tumor (Fig. 1d) and tumor markers (NSE and ProGRP) became normal.
Histopathological findings of the lung specimens. (a) Hematoxylin and eosin staining of the lung tissue obtained by bronchoscopic biopsy, showing histopathology of adenocarcinoma. (b) Immunohistochemical staining of thyroid transcription factor 1, demonstrating strong nuclear expression in tumor cells. (c) Post-afatinib, hematoxylin and eosin staining of lung tissue showed small cell lung cancer transformation. (d) Post-afatinib, immunohistochemical staining of lung tissue showed strong staining for CD56.
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Bronchoscopic biopsy was performed targeting the mass in the left upper lobe, and he was histologically diagnosed with lung adenocarcinoma (cT1bN1M1a, stage IV) (Fig. 2a and b). Histological assessment indicated SCLC (Fig. 2c and d).