Neuroendocrine structures in normal and diseased human lung.

Area of Science:

• Pulmonology
• Oncology
• Pathology

Background:

• Advancements in histological, immunohistochemical, and ultrastructural data necessitate a revised classification of neuroendocrine lung lesions.
• Current classifications may not fully encompass the spectrum of neuroendocrine lung carcinomas observed in surgical pathology.

Purpose of the Study:

• To provide further support for a recently proposed updated classification of neuroendocrine lung carcinomas.
• To analyze surgical lung specimens to refine the categorization of neuroendocrine lung neoplasms.

Main Methods:

• Histological examination of surgical lung specimens, including HE, Alcian PAS, and Grimelius silver impregnation.
• Analysis of 58 squamous cell carcinomas, 58 adenocarcinomas, 6 large cell carcinomas, 27 neuroendocrine carcinomas, and 30 non-tumorous cases.
• Illustration of neuroendocrine cells and neuroepithelial bodies, detailing pathological changes from hyperplasia to neoplasia.

Main Results:

• Demonstration of neuroendocrine cells and neuroepithelial bodies in various pathological states within lung tissues.
• Identification of distinct morphological features supporting a tiered classification of neuroendocrine lung carcinomas.
• Observation of pathological progressions including hyperplasia, dysplasia, and overt neoplasia.

Conclusions:

• A proposed classification for neuroendocrine carcinomas (NEC) is presented: typical carcinoids (NECNID), well-differentiated (NECWED), intermediate/poorly differentiated (NECINT), and small cell (NECMIC).
• This classification aims to better categorize neuroendocrine lung lesions found in surgical material.
• The findings support the need for revised diagnostic criteria for neuroendocrine lung neoplasms.