Endocrine Abstracts

Pasireotide is a a synthetic polypeptide second-generation somatostatin analogue that can be used in the treatment of GH- and ACTH- secreting pituitary neuroendocrine tumors (PitNETs), however, there are single reports of pasireotide treatment in other subtype of PitNETs. We present a case series of aggressive, giant PitNETs treated with pasireotide alone or as multimodal therapy.

Case 1: A 33-year-old male reported to the Clinic due to severe headaches and vomiting. In MRI pituitary mass 33×39×55 mm and a cerebral oedema were revealed. TSS with external ventricular drainage were performed. Histopathology results showed densely granulated silent corticotroph adenoma subtype 1, Ki67<1%. After 3 months, MRI showed tumour progression to 39×40×30 mm. Two emergency TSS followed by stereotactic radiotherapy were performed. Combined therapy with cabergoline and temozolomide was introduced. Due to sever headaches pasireotide was introduced. After 18 months, stabilization of the disease was observed with complete remission of headaches.

Case 2: A 59-year-old male underwent transsphenoidal surgery (TSS) ten years ago due to severe headaches and visual deficits. Histopathology results showed partially acidophilic adenoma (FSH- LH- GH- ACTH- PRL-). Control MRI showed tumour regrowth - 56×56×89 mm mass invading local structures. The patient was qualified for radiotherapy, to which he did not consent. Due to the progression of symptoms, temozolomide and pasireotide were introduced. After 5 months, significant improvement in headaches and vision was observed. In MRI stable pituitary mass was noted.

Case 3: A 59-year-old male presented with severe headaches and life-threatening tumour mass effect. In MRI a 48x48x33mm mass was observed. The patient underwent two non-radical TSS, 4 cycles of pasireotide, and cyberknife treatment. Histopathology showed gonadotroph PitNET, Ki<67%. MRI showed tumour shrinkage to 45×46×29 mm, with persistent severe headaches. The patient was re-qualified for pasireotide treatment.

Case 4: A 17-year-old male with dopamine resistant giant prolactinoma underwent after recent two non-radical surgeries presented in the clinic due to daily severe headaches and peripheral vision loss. In control MRIs progressing mass 38×34×33 mm invading local structures was observed. Due to worsening of the symptoms, pasireotide was introduced resulting in a decrease of headaches and improvement in vision. The tumour size remained stationary.

Conclusion: Our study demonstrates the clinical potential and the efficacy of pasireotide treatment in aggressive, giant PitNETs. The therapy alone, or in combination has a potential role to reduce the tumour size, decrease the headaches, and allows the stabilization of the disease.