Endocrine Abstracts

Introduction: Giant pituitary adenomas are defined as tumors with a largest diameter of ≥40 mm. They are characterized by high invasiveness, causing compression of adjacent structures and hormonal dysfunction. The aim of this case report is to highlight the diagnostic, therapeutic, and prognostic challenges associated with this rare entity.

Case report: A 35-year-old male, diagnosed with diabetes under insulin therapy, along with Hashimoto’s thyroiditis managed with levothyroxine, presented urgently with a sudden onset of headache, vomiting, and a decline in bilateral visual acuity. Magnetic Resonance Imaging (MRI) of the head revealed a substantial 60x34 mm lesion in the sellar and suprasellar regions, causing compression of the optic pathways and V3, accompanied by active hydrocephalus. Laboratory investigations indicated gonadotropin deficiency, a slightly elevated prolactin level of 39.9 ng/mL, and cortisol at 15 µg/dl. Visual field examination revealed a complete loss of vision in both eyes. The patient underwent surgical removal of the cerebral lesion via a trans-sphenoidal approach. Histopathological examination identified a pituitary adenoma (PA) expressing growth hormone (GH), prolactin, and thyroid-stimulating hormone (TSH). Postoperatively, the patient developed diabetes insipidus and corticotrope deficiency. The patient is under hormonal medical treatment, including hydrocortisone (15 µg/day), levothyroxine (100 mg/day), desmopressin (60 µg, 2 tablets/day), and androtardyl. At the three-month follow-up, imaging revealed a sellar and suprasellar lesion involving both cavernous sinuses, measuring 44.3×36×36.4 mm. Repeat surgery was indicated, with treatment plans incorporating dostinex and somatuline 120 mg LP. Unfortunately, the patient died immediately post-operatively.

Discussion: Giant pituitary adenomas are uncommon tumors, with a prevalence estimated at 6-10% of all pituitary adenomas. They present a therapeutic challenge due to their size, invasiveness, and frequent extrasellar extensions. The initial presentation is determined by the lesion’s mass effect and hormonal dysfunction. Surgery remains the treatment of choice, although achieving complete tumor excision in such large tumors is challenging. Histopathological study with immunostaining is crucial to confirm the diagnosis and define medical therapy. The literature reports high mortality rates following excision of giant pituitary adenomas.

Conclusion: Giant pituitary adenomas represent a challenge in clinical endocrinology, requiring multidisciplinary management in diagnosis, therapeutic management, and long-term follow-up.