Definitions and Explanatory Notes

Abstract

Adenohypophyseal tumours, almost all of which are adenomas, have been variously classified on the basis of their clinical presentation, biochemical findings, histology (growth pattern and tinctorial characteristics), proliferation activity, immunocytochemical profile, and ultrastructural features. Herein, we propose a five-tier classification, clinicopathological in nature, which focuses not only upon histology, immunocytochemistry (Table 3, p. 20), ultrastructure (Table 4, p. 22), but endocrine activity (Table 5, p. 26) and imaging, as well as operative findings (Table 6, p. 28). In the case of pituitary tumours, integration of these five complementary approaches to what is fundamentally a pathological classification is practical. It provides valuable information to clinical endocrinologists, neurosurgeons, and oncologists involved in the assessment of a tumour’s biological behaviour, growth potential, therapeutic responsiveness, and prognosis. Due to financial constraints, lack of facilities, and unavailability of well-trained personnel, it is recognised that the five approaches cannot be fully implemented worldwide. Nonetheless, in addition to basic histological parameters, clinical and biochemical data as well as imaging and operative findings are generally readily available. Collectively, they are indispensable in establishing a correct diagnosis and in directing patient management.