Endocrine Abstracts

Background: Pituitary adenomas (PA) are slow-growing, benign intracranial tumors. Rarely, they can be histologically and clinically aggressive.

Aim: To present a case of corticotroph PA with aggressive behavior following a long indolent interval after the initial surgery.

Case presentation: A 47 years old female presented in Nov 2007 with right temporal hemianopsia and left eye blindness, associating type 2 DM and severe mixed dyslipidemia. MRI demonstrated a 22 × 20 × 25 mm sellar tumor with suprasellar extension. Vision improved significantly following transsphenoidal resection. The patient was lost to follow-up for 12 years, during which she was symptom-free, despite persistence of a significant tumor remnant (21 × 19 × 16 mm, MRI in 2011). In Mar 2019, the 59 years old patient returned to our unit, with bitemporal hemianopsia and decreased visual acuity, insulin-requiring DM and dyslipidemia, central obesity, without other signs of Cushing’s syndrome. 0800 h cortisolemia (21.13 mg/dl) was unsuppressed by 1 mg o/n DEX (5.85 mg/dl) and LDDST (3.39 mg/dl) and 0800 h ACTH was 26 pg/ml. The patient had thyrotroph, gonadotrop and likely somatotroph insufficiency. A partial transsphenoidal resection of a fibrous, difficult-to-resect tumour, led to biochemical remission of Cushing’s disease (CD) (0800 h cortisolemia = 5.2 mg/dl and 0.66 mg/dl after 1 mg o/n DEX) but no visual improvement. Post-operative MRI revealed a 25 × 18 × 30 mm tumor with bilateral cavernous sinus invasion and chiasmal compression. A third transsphenoidal resection improved visual fields and acuity significantly and the patient developed corticotroph insufficiency (8AM cortisolemia = 1.46 mg/dl, ACTH = 6.6 pg/ml). Histopathological examination revealed a PA with frequent mitoses, IHC positivity for ACTH only, Ki-67 index 15% and p53 nuclear labeling in 30% of cells. SSTR2 and SSTR5 tumor immunoreactivity was positive, but pasireotide could not be administered for regulatory reasons. Visual fields and acuity declined progressively over 3 months and MRI in Jan 2020 revealed rapid tumor growth (27/30/33 mm). MDT recommendations were for repeat surgery (pending) followed by radiotherapy +/– temozolomide and close follow-up.

Conclusion: We report a case of aggressive functioning corticotroph adenoma occurring after a twelve years indolent interval. Immunohistochemical markers of proliferation predict an unfavourable clinic course and need of multimodal aggressive management. Combined temozolomide and radiotherapy (Stupp protocol) is a possibility.