Intranuclear cytoplasmic pseudoinclusions in pituitary adenomas

Area of Science:

• Endocrinology
• Pathology
• Cell Biology

Background:

• Intranuclear pseudoinclusions are documented in various human tumors.
• Previous reports on intranuclear inclusions in human adenohypophyseal cells are limited.
• The prevalence and nature of these inclusions in pituitary adenomas require further investigation.

Purpose of the Study:

• To investigate the frequency of intranuclear cytoplasmic pseudoinclusions in pituitary adenomas.
• To differentiate these inclusions from those in normal pituitary tissue.
• To elucidate the origin and characteristics of intranuclear inclusions in pituitary adenomas.

Main Methods:

• Histopathological examination of 138 pituitary adenomas and 9 normal pituitary tissues.
• Electron microscopy for ultrastructural analysis of inclusions.
• Immunostaining to assess the composition and origin of inclusions.

Main Results:

• Intranuclear cytoplasmic pseudoinclusions were found in 70.3% of pituitary adenomas versus 11.1% in normal pituitary tissue.
• The frequency of these pseudoinclusions was similar in both functional and non-functional pituitary adenomas.
• Electron microscopy and immunostaining confirmed inclusions originate from cytoplasmic invagination, containing cytoplasmic organelles and exhibiting identical immunoreactivity.

Conclusions:

• Intranuclear cytoplasmic pseudoinclusions are a frequent finding in pituitary adenomas (70.3%).
• These inclusions are consistently formed through cytoplasmic invagination.
• The study proposes the term 'intranuclear cytoplasmic pseudoinclusions' for these specific pituitary findings.