Large cell neuroendocrine carcinoma of the lung: radiologic and pathologic findings

The purpose of this work was to determine the radiologic and pathologic findings of large cell neuroendocrine carcinoma (LCNEC).

We retrospectively evaluated chest radiographs, CT scans, and pathologic findings of five patients with pathologically confirmed LCNEC. They were confirmed by percutaneous needle biopsy (n = 2) and by surgery (n = 3). The average age of patients was 60 (51-70) years, and all five were smokers (mean 30 pack-years) and men. Radiologic findings were reviewed for the pattern of lesion, location, and associated findings by two radiologists under consensus. Pathologic findings were reviewed by two pathologists.

In all five patients, tumors were represented as a peripherally located nodule or mass without associated secondary pneumonitis or distal atelectasis radiographically. On CT scan, masses were oval or round and well demarcated with lobulated margin in all cases, their sizes ranged from 2 to 5 cm, and they did not show internal calcification and necrosis. On contrast-enhanced CT, three cases showed moderate enhancement more than the chest wall muscle. Lymphadenopathy was observed in ipsilateral hilar and mediastinal areas in three cases. Distant metastasis to liver was noted in one case. One case of LCNEC was Stage IV, two were Stage IIIa, and two were Stage Ia at the time of diagnosis.

Although the epidemiology of LCNEC is more similar to that of small cell carcinoma than atypical carcinoids, in its strong association with smoking, rapid progression, and poor prognosis, our five cases of LCNEC show peripherally located pulmonary nodule or mass with or without regional lymphadenopathy, which are findings similar to those of atypical carcinoids rather than small cell carcinoma.