Endocrine Abstracts

Pituitary adenohypophyseal tumors are considered benign and termed “adenomas” but can also be invasive, “aggressive” and malignant with metastases (carcinoma). Taking into account this variability in behavior and the oncological definition, pathologists have proposed changing the term adenoma to tumor. Indeed, “tumor designates a neoplasm which is benign or malignant”. The invasion of the surrounding tissues is a criterion of malignancy. For this reason, the terms “invasive adenoma or aggressive adenoma” are inappropriate pathologically. Recently, a Workshop of Endocrinologists (PANOMEN) recommended that the term adenoma be retained, arguing that “tumor may have a sinister tone and may adversely affect patients”. What is your opinion? These tumors are classified into seven morphofunctional types and three lineages identified by transcription factors: lactotroph, somatotroph and thyrotroph (PIT1 lineage), corticotroph (TPIT lineage) or gonadotroph (SF1 lineage), null cell or immunonegative tumors and plurihormonal tumors. The WHO 2017 classification suggested that subtypes, such as male lactotroph, silent and “Crooke cell” corticotroph, sparsely granulated somatotroph, and silent plurihormonal PIT1 tumors, should be considered as “high risk” tumors. However, the prognostic impact of these subtypes remains controversial. In contrast, the French five-tiered classification, taking into account invasion (MRI), the immuno-histochemical type, and proliferative markers (Ki-67 index, mitotic count, p53 positivity), has prognostic value for recurrence/progression, that has been independently validated by statistical analysis on around 2000 patients. In the European Society of Endocrinology (ESE) cohort of “aggressive” tumors (125 APC) and carcinomas with metastases (40 PC), the clinical and pathological features were similar. This cohort (APT+PC) differed greatly from a reference surgical cohort, especially in the percentage of tumors with Ki67 ≥ 10%. We suggest that these clinically aggressive, invasive and highly proliferative tumors represent tumors with malignant potential. Pathological diagnosis may help clinicians to adapt post-operative management, including appropriate follow-up and early recognition and treatment of potentially malignant tumors.