Spontaneous histological transformation of lung squamous-cell carcinoma to large cell neuroendocrine carcinoma and small cell lung cancer

Abstract

Background: Histopathological transformation between different types of lung cancer cells has been reported following a variety of anti-tumor treatments. Examples include transformation from lung adenocarcinoma to squamous-cell carcinoma (SCC) and transformation from non-small cell lung cancer (NSCLC) to small cell lung cancer (SCLC).

Case report: A patient with intermittent hemoptysis for 2 days underwent a computed tomography (CT) scan that revealed interstitial pneumonia in addition to two enlarged paratracheal lymph nodes: one on the right (4R) and one on the left (4L) measuring 10 and 7 mm in diameter, respectively (Fig. 1). There was no evidence of a lung or bronchial mass. Bronchoscopy identified an endoluminal primary mass in a superior segmental bronchus of the left lower lobe and pathological examination following surgery confirmed it to be SCC. At 15 months post operation, a CT scan detected that the 4R lymph node had increased in size from 10 to 16 mm in diameter. At the next follow-up 7 months later, a CT scan showed that the R4 lymph node had further increased in size from 16 to 40 mm in the short axis, making it difficult for a surgeon to resect it "en bloc" immediately. The maximum standardized uptake value was 7.5 on PET-CT images. One month following completion of one cycle of neoadjuvant chemotherapy with gemcitabine and nedaplatin, a further CT scan indicated that the lymph node had decreased in size from 40 to 30 mm in the short axis. A complete mediastinal lymphadenectomy via open thoracotomy was performed and the lymph node was resected. Histological examination identified a main large cell neuroendocrine carcinoma (LCNEC) component with a small fraction of small cell carcinoma, confirmed by immunohistochemical analysis and genetic evidence.

Conclusion: Histopathological transformation from SCC to LCNEC with a small fraction of SCLC may have occurred spontaneously without any treatment.

Keywords: Exome sequencing; Histopathological transformation; Immunohistochemical examination; Lung cancer.