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pulmonary neuroendocrine tumors

Monday 14 October 2013

Pulmonary neuroendocrine (NE) proliferations; neuroendocrine tumors of the lung

WP

Definition: Pulmonary neuroendocrine tumors are neuroendocrine tumors localized to the lung: bronchus or pulmonary parenchyma.

Pulmonary neuroendocrine tumors include a spectrum of tumors from the low-grade typical pulmonary carcinoid tumor and intermediate-grade atypical pulmonary carcinoid tumor to the high-grade pulmonary large cell neuroendocrine carcinoma (LCNEC) and pulmonary small cell carcinoma (SCLC), with significant clinical, epidemiologic and genetic differences.

Pulmonary neuroendocrine (NE) proliferations are a diverse group of disorders which share distinct cytological, architectural and biosynthetic features.

Classification

Pulmonary neuroendocrine tumor are classified according to tumoral grade:

- Low grade pulmonary neuroendocrine tumor

  • Typical pulmonary carcinoid tumour (TC; low-grade)
  • Low-grade nodular neuroendocrine proliferations ≥ 0.5 cm are classified as carcinoid tumors and smaller ones are called pulmonary tumorlets.

- Intermediate-grade pulmonary neuroendocrine tumor

  • Atypical pulmonary carcinoid tumour (AC; intermediate-grade)

- High-grade pulmonary neuroendocrine tumor

  • Small cell lung cancer (SCLC)
  • Large cell neuroendocrine carcinoma (LCNEC of the lung)

When neuroendocrine cell hyperplasia and tumorlets are extensive, they represent the rare preinvasive lesion for carcinoids known as "diffuse idiopathic pulmonary neuroendocrine cell hyperplasia".

Both LCNEC and SCLC can demonstrate histologic heterogeneity with other major histologic types of lung carcinoma, such as pulmonary adenocarcinoma or pulmonary squamous cell carcinoma, but is not characteristic of TC or AC.

References

- Neuroendocrine tumours—challenges in the diagnosis and classification of pulmonary neuroendocrine tumours. MA den Bakker1, FBJM Thunnissen. J Clin Pathol doi : 10 1136/jclinpath-2012-201310