Large cell neuroendocrine carcinoma of the lung

Large cell neuroendocrine carcinoma (LCNEC) of the lung is classified as a subtype of large cell carcinoma of the lung. It is also classified as a pulmonary neuroendocrine tumor.

Epidemiology

The incidence peaks around the 6^th decade ⁶. There is an increased male predilection ⁷. They are rare and may accounts for ∼3% of all lung cancers, although the proportion of lung cancers diagnosed as large cell neuroendocrine carcinoma may be increasing ¹².

Pathology

Large cell neuroendocrine carcinoma of the lung is poorly differentiated and high-grade neuroendocrine tumors ¹⁰. 

They have neuroendocrine morphology, neuroendocrine differentiation on immunohistochemistry, often high mitotic rates (>10 mitoses/mm²) and non-small cell cytological features ¹². 

As with other neuroendocrine cells of the lung, large cell neuroendocrine carcinoma arises from Kulchitsky cells of the bronchial mucosa ³.

Associations

There is a strong association with smoking ¹¹.

Radiographic features

CT

CT features are non-specific. Large cell neuroendocrine carcinomas, in general, tend to present as oval-to-round and well-demarcated masses with lobulated margins. Their size typically ranges from 2 to 5 cm. Internal calcification is uncommon (9-21%) ^2,4,7. A slight peripheral predilection may be present ⁵. There can be homogeneous or inhomogeneous enhancement following contrast ¹.

Treatment and prognosis

They tend to be aggressive high-grade tumors with a poor prognosis ⁶. The overall prognosis is thought to be between that of an atypical pulmonary carcinoid and small cell lung cancer ³.