Endocrine Abstracts

A proportion of prolactinomas exhibit aggressive features (including invasiveness, relevant growth despite adequate dopamine agonist treatment, and recurrence potential) and few may exhibit metastasizing potential (carcinomas). We present an uncommon case of intra-orbital spread from a large infiltrative prolactinoma, with excellent response to temozolomide and a systematic review of the literature. A 55y.o male patient presented with generalized weakness and hyponatraemia. Further investigations revealed hypopituitarism (cortisol: 24nmol/l, TSH: 1.01mIU/l, fT4 9.0nmol/l, testo 0.4nmol/l) and markedly elevated prolactin (PRL: 23937mU/l). A contrast enhanced MRI pituitary demonstrated a 27x16x16mm neoplasm, extending into the right Meckel’s cave encroaching the internal carotid artery. The neoplasm was slightly compressing the optic chiasm. Initial management included Cabergoline 0.25mg BW, hydrocortisone 10mg BD and thyroxine 50mg OD. After 2 months the patient developed pituitary apoplexy which required transphenoidal surgery (TSS). Histology showed Pit-1 positive pituitary adenoma with extensive haemorrhagic necrosis and few positive PRL cells. Ki67 was 8-9%. Postoperatively PRL reduced to 1577mU/l, but despite high cabergoline doses (1mg OD), PRL continued to rise to 30707mU/l. Progression of the residual soft tissue and extension into the right orbit via the right superior and inferior orbital fissures was confirmed on MRI imaging. Treatment with temozolomide (TMZ) 390 mg OD for 5 days every 28 days for 12 cycles was trialed after discussion in the pituitary MDM without significant side-effects. Cabergoline was decreased to 0.5mg BW and after 10 cycles of TMZ biochemical remission (PRL: 411mU/l) was achieved with remarkable radiological improvement. Prolactinomas are the most common functioning pituitary neoplasms with the majority being responsive to medical treatment. However, up to 15% of cases are resistant and locally invasive and depict an aggressive behavior. This case demonstrates the efficacy and safety of TMZ post-TSS for aggressive PRLoma management and need for multidisciplinary approach to managing complex PRLoma cases.