PMC9482961_01
CT scan and 18F-FDG PET-CT. CT scans (A and B) and 18F-FDG PET-CT (C) at initial diagnosis. (A) The nodule in the right middle lobe indicated by an arrow was the primary lesion of the lung cancer. (B) Scattered nodules in the interlobar pleura indicated by arrows were disseminated lesions. Right pleural effusion was detected in both images. (C) FDG uptake at the nodule in the right middle lobe was high, the maximum standardized uptake value was 6.1.
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A chest X-ray during a medical checkup in June 2010 showed a 20-mm nodule in the right lung, and a chest computed tomography (CT) scan in July 2010 showed a 26 mm nodule in the medial segment of the middle lobe, a right pleural effusion, and scattered nodules in the interlobar pleura (Figure 1A and B). The maximum standardized uptake value (SUVmax) was 6.1 (Figure 1C).
Cytological examination of pleural effusion. The pleural effusion was positive for adenocarcinoma cells (scale bar: 100 mum).
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Biopsy of the lung nodule from the medial segment obtained by bronchoscopy and cytology of the pleural fluid obtained by thoracic puncture confirmed lung adenocarcinoma (Figure 2).
CT scan and 18F-FDG PET-CT after treatment with 4 cycles of cisplatin, pemetrexed, and bevacizumab. (A and B) The nodule in the right middle lobe indicated by an arrow (A) and the nodules in the interlobar pleura indicated by arrows (B) decreased in size, and the right pleural effusion resolved after treatment. (C) FDG uptake was negative at the reduced nodule after treatment.
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August 2010, the patient received cisplatin (75 mg/sq), pemetrexed (PEM, 500 mg/sq), and bevacizumab (BEV, 1000mg/body) as first-line chemotherapy. After 4 cycles of chemotherapy, the tumor size decreased to 1 cm in diameter, and pleural effusion had disappeared; the 61.5% reduction in tumor size indicated that partial response was achieved according to the Response Evaluation Criteria in Solid Tumors version 1.1 (Figures 3A and B). PET-CT revealed that FDG uptake was negative in the tumor (Figure 3C).
Time course of treatment and laboratory findings.
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The tumor marker CEA levels decreased to 2.4 ng/mL, which was within the normal range (Figure 4).
Histological examination of surgical specimens. (A) Gross findings of the resected right middle lobe revealed the residual tumor as a fibrotic nodule indicated by the white square (scale bar: 2 cm). (B) Histological findings at low power revealed alveolar collapse, fibrosis, and some tumor cell clusters with no exposure to the pleural surface indicated by the yellow ellipse (scale bar: 2 mm). (C) Histological examination of atypical cells with nuclear enlargement at high power consistently showed adenocarcinoma (scale bar: 100 mum). (D) Immunohistological staining revealed that tumor cells were positive for TTF-1 (scale bar: 100 mum). (E) Immunohistological staining revealed that 5% of the tumor cells were positive for MIB-1 (scale bar: 100 mum). (F) Lymph node metastasis in the #7 lymph node of the surgical specimen (scale bar: 100 mum).
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Macroscopic examination of the specimen from the right middle lobectomy revealed that the tumor nodule became a fibrotic lesion adjacent to the pleura (Figure 5A). Upon histological examination, solid tumor cell clusters were observed among lung tissue with collapsed alveoli and fibroelastosis (Figures 5B and C). Hence, the tumor cells were diagnosed as residual adenocarcinoma (Figures 5D and E). Additionally, low-volume metastasis in the #7 lymph node was confirmed by histological examination (Figure 5F).