Pituitary neuroendocrine tumours (PitNETs) commonly present with symptoms related to mass effect or hormonal dysfunction, including headache, visual disturbances, and endocrine abnormalities. However, atypical presentations without neurological or hormonal "red flag" symptoms may delay diagnosis, particularly in primary care settings where benign upper respiratory conditions are more frequently encountered. We report the case of a 56-year-old postmenopausal woman who presented with a five-month history of persistent postnasal drip, chronic non-productive cough and a sensation of nasal congestion characterised by fullness in the nasal and retro-orbital region. Despite conservative medical management, persistent symptoms prompted a computed tomography (CT) of the brain and paranasal sinuses, which unexpectedly revealed a sellar mass extending into the left sphenoid sinus. Subsequent magnetic resonance imaging (MRI) confirmed a 3.4cm pituitary macroadenoma with left cavernous and sphenoid sinus invasion, left internal carotid artery encasement, optic nerve involvement, and imaging features of pituitary apoplexy. Hormonal evaluation showed hyperprolactinaemia, and histopathology following endoscopic endonasal resection confirmed a lactotroph PitNET. This case highlights the importance of diagnostic reassessment in patients with persistent symptoms and demonstrates that clinically significant PitNETs can masquerade behind common benign upper respiratory conditions.

BACKGROUND Carotid-cavernous fistulas (CCFs) are abnormal arteriovenous communications between the carotid artery and cavernous sinus. They may be direct or indirect and commonly present with both ocular and neurovascular symptoms. Endovascular embolization is the main treatment, with high rates of fistula obliteration and clinical improvement. Although generally safe, complications can occur, including cranial nerve dysfunction and vascular injury. Endocrine complications following carotid-cavernous fistula embolization are exceedingly rare. To our knowledge, only 1 case of syndrome of inappropriate antidiuresis (SIAD) after Onyx embolization has been reported in the literature. CASE REPORT A 72-year-old woman developed severe symptomatic SIAD 9 days after transarterial Onyx embolization of an indirect CCF. The procedure was successful but associated with worsening of preexisting left abducens nerve paresis. She subsequently re-presented with dizziness, truncal ataxia, and confusion, which resulted in a fall involving wrist fracture but no head strike. Investigations demonstrated profound hypotonic euvolemic hyponatremia with elevated urine osmolality and urine sodium, suggestive of SIAD. The absence of hypovolemia, polyuria, and a negative fluid balance argued against cerebral salt wasting. Adrenal insufficiency, hypothyroidism, and other causes were excluded. Treatment with hypertonic saline and fluid restriction resulted in gradual sodium correction and complete neurological recovery. CONCLUSIONS Transient hypothalamic-pituitary dysfunction related to Onyx-associated local mass effect and hemodynamic changes may represent a plausible mechanism. This case highlights delayed-onset SIAD as a rare but clinically significant complication temporally associated with CCF embolization. The findings support consideration of both early and delayed electrolyte monitoring, particularly within the first 1 to 2 weeks after the procedure.

Peptide receptor radionuclide therapy (PRRT) is an emerging and promising targeted treatment for aggressive pituitary neuroendocrine tumours (PitNETs) and pituitary carcinomas refractory to conventional therapies. Its use is supported by the frequent expression of somatostatin receptors (SSTR), predominantly SSTR2, in pituitary tumour cells, enabling selective delivery of β-emitting radionuclides such as 177Lu-DOTATATE and 90Y-DOTATOC, resulting in targeted antitumour and antisecretory effect. This narrative review summarizes current scanty evidence on PRRT efficacy and safety in aggressive pituitary tumours. Successful outcomes were reported in some cases, in terms of tumour growth and/or hormonal reduction, or relief of mass-effect-related symptoms. PRRT related adverse events are mostly mild and transient, predominantly hematologic, with clinically significant renal toxicity uncommon when amino-acid nephroprotection is used. Preserved pituitary function and no clinically significant PRRT-induced hypopituitarism have been reported. Overall, PRRT represents a biologically rational and potentially effective option for selected patients with SSTR-positive aggressive PitNETs after failure of previous therapies.