Endocrine Abstracts

Introduction: Pituitary adenomas stand as the most prevalent form of tumorous pathology impacting the pituitary gland in adults. Their discovery might arise from either hypersecretion in functional adenomas or the manifestation of compression symptoms on neighboring structures. Detection of a pituitary adenoma can occur incidentally during various imaging modalities, encompassing both structural and functional assessments. This study documents a case involving the incidental detection of a pituitary macroadenoma during a PET-CT scan.

Observation: We report the case of a 61-year-old patient with a history of large B-cell gastric lymphoma evolving over four years, managed with chemotherapy. A post-chemotherapy evaluation was conducted through an 18FDG PET-CT scan. The scan revealed a significantly increased metabolic activity in the sellar region associated with tissue infiltration. A hypothalamic lymphomatous localization was deemed unlikely as there was no pathological metabolic activity observed in lymph nodes or in the gastric region. Clinical examination and laboratory tests showed no signs of hormonal overproduction or pituitary deficiency. An MRI of the pituitary gland confirmed the presence of an expansive intra-sellar process, demonstrating heterogeneous enhancement after gadolinium injection, measuring 17×15×14 mm, exerting a mass effect on the optic chiasm. Visual field examination revealed no abnormalities. The diagnosis of a non-secreting pituitary macroadenoma with suprasellar extension was established. The patient was referred to neurosurgery for further management.

Discussion et conclusion: The discovery of an incidental pituitary adenoma through an 18FDG PET scan is exceedingly rare. This rarity in discovery and the lack of definitive correlation between FDG uptake and functional status raise questions about the metabolic behavior of these tumors. Understanding the mechanism of uptake in non-secreting adenomas could potentially unveil novel insights into their biology and pathogenesis. This aspect of our research highlights the complexity of pituitary adenomas and emphasizes the need for further investigations into their metabolic characteristics to elucidate their clinical significance and management.