Pituitary carcinoma: reclassification and implications in the NET schema

Area of Science:

• Endocrinology
• Oncology
• Pathology

Background:

• Pituitary carcinoma traditionally defined by metastasis, irrespective of histology.
• Existing classification challenges due to reliance on spread rather than local invasion.
• Need for revised classification reflecting tumor behavior and potential harm.

Purpose of the Study:

• To discuss the reclassification of pituitary tumors.
• To propose classifying pituitary tumors as neuroendocrine tumors.
• To align pituitary tumor classification with broader neuroendocrine neoplasm guidelines.

Main Methods:

• Review of traditional and proposed classification systems for pituitary tumors.
• Analysis of diagnostic criteria for malignancy in pituitary lesions.
• Comparison with World Health Organization/International Agency for Research on Cancer (WHO/IARC) classifications.

Main Results:

• Traditional definition of pituitary carcinoma based solely on metastasis is being challenged.
• Proposed classification as pituitary neuroendocrine tumors acknowledges variable behavior, including local invasion.
• WHO/IARC classification reserves 'neuroendocrine carcinoma' for high-grade, poorly differentiated tumors.

Conclusions:

• Reclassification to pituitary neuroendocrine tumors offers a more comprehensive approach.
• Distinction between adenoma and carcinoma may become obsolete under the new framework.
• Further research is needed to identify true pituitary neuroendocrine carcinomas.