A 52-year-old man with a 30-year history of smoking presented with an abnormal nodule measuring 0.8 × 1.5 cm in the left upper lung lobe imaged through chest computed tomography (CT) scanning in March 2012 in a community hospital.
He had previously been well without any additional relevant or abnormal symptoms.
Physical examination suggested no significant abnormalities.
Laboratory findings were within normal range, except for a carcinoembryonic antigen (CEA) level of 30.25 ng/mL (normal range, 0–5 ng/mL) found in the serum.
Subsequently, a positron emission tomography (PET)/CT scan showed a lung lesion with a standardized uptake value of 7.94, which was highly suspected to be a malignant tumor (Fig.1).
Subsequently, he underwent left upper lung lobectomy and lymph node dissection.
Postoperative pathological examination revealed an adenocarcinoma (ADC) (Fig.2A).
Immunohistochemistry (IHC) staining results were positive for CK7, TTF-1, p63, and NapsinA and negative for CK 5/6, Syn, cgA, and Ki-67 (20%–30%).
The clinical stage was classified as IA2 (pT1bN0M0).
Because the tumor was still in an early stage, the patient did not receive adjuvant treatment but continued to be monitored through regular hospital visits every 3 months.
The patient's condition had been stable until the onset of left chest pain in April 2015.
The patient was transferred to our hospital (a tertiary care hospital) for further treatment.
Physical examination suggested a significant tender point in the left chest wall.
Laboratory findings showed only a single parameter outside the normal range: the cytokeratin19 fragment antigen 21–1 (CYFRA21–1) level was 17.45 ng/mL in the serum (normal range = 0–3.3 ng/mL).
CT and PET/CT scans highlighted the serious involvement of left pleura, showing bilateral lung lesions (Fig.3A and E).
At that point, the clinical stage was upgraded to IVB.
After the CT-guided left pleura puncture, pathological IHC analysis showed positive staining for p63, p40, CK 7, and CK 5/6, while TTF-1 and NapsinA staining were absent, supporting a diagnosis of squamous cell carcinoma (SCC) (Fig.2B).
Meanwhile, molecular evaluation confirmed an L858R mutation in exon 21 and a T790M mutation in exon 20 (Fig.4B and C).
Considering the pathology of the SCC was quite distinct compared with that of the originally resected NSCLC specimen, we retrospectively reassessed the surgery specimen to verify our primary diagnosis.
The morphologic and IHC results were in complete agreement with the initial diagnoses, but an L858R mutation was identified using the newly added molecular evaluation (Fig.4A).
To relieve the acute pain in the left pleura as quickly as possible, palliative three-dimensional conformal radiotherapy (3D-CRT) for the chest lesion was delivered at a total dose of 42 Gy/14 fractions (f), once daily and 5f/week (Fig.5).
The volume over radiation dose 5 Gy (V5) values of the left, right, and total lungs were 20%, 0%, and 7.8%, respectively; the volume over radiation dose 20 Gy (V20) values were 10%, 0%, and 5%, respectively; the mean lung dose (MLD) was 5 Gy.
Meanwhile, considering the MST pathology was that of SCC, the patient received GP chemotherapy (cisplatin 75 mg/m2 d1, gemcitabine 1250 mg/m2 d1, d8, for 21 days as a cycle) for 4 cycles, and the patient achieved partial remission (PR) after 2 cycles, followed by stable disease (SD) after 4 cycles (Fig.3[B3[B and F] and [C and G]) according to response evaluation criteria in solid tumors (RECIST) 1.1.
Then, gefitinib (150 mg qd) was used as maintenance treatment from November 2015 onward.
During the treatment, Ibandronate sodium was given monthly for skeletal-related events.
The patient is currently under surveillance with SD (Fig.3D and H) and with PS scores of 0.