ABSTRACT
Ectopic pituitary adenomas are a rare clinical entity and are frequently mistaken for other base of skull lesions on imaging. We report the clinical presentation and management of a woman presenting with an ectopic prolactinoma located in the clivus. A 66-year-old female presented with a 6-month history of headaches and light-headedness. Anatomical imaging demonstrated a clival lesion most suspicious for chordoma. Endocrinological assessment revealed modestly increased prolactin level with lower-than-expected gonadotrophins levels for her age. Surgical resection confirmed an ectopic prolactinoma. A skull base lesion in a patient with hormonal derangement should lend to a high clinical suspicion of an EPA as they may be treated with medications before surgery. Guidelines could assist clinicians investigating skull-based lesions to identify the rare, but important diagnosis of ectopic pituitary adenomas.
ABSTRACT
Phaeochromocytomas and paragangliomas (PPGLs) are rare tumours that arise from the adrenal medulla or extra-adrenal sympathetic or parasympathetic paraganglia. Recent advances in genetics have greatly enhanced understanding of the pathogenesis and molecular physiology of PPGL. Concomitantly, advances in molecular imaging mean four techniques are now available for use in PPGLs: [123 I]-MIBG coupled with SPECT/CT; [18 F]- FDG, [68 Ga]-DOTATATE and [18 F]-FDOPA coupled with PET/CT. Each modality relies on unique cellular uptake mechanisms that are contingent upon the tumour's molecular behaviour-which, in turn, is determined by the tumour's genetic profile. This genotype-phenotype correlation means the appropriate choice of radiotracer may depend on the known (or suspected) underlying genetic mutation, in addition to the clinical indication for the scan-whether confirming diagnosis, staging disease, surveillance or determining eligibility for radionuclide therapy. Given these rapid recent changes in genetic understanding and molecular imaging options, many clinicians find it challenging to choose the most appropriate scan for an individual with PPGL. To this end, recent guidelines published by the European Association of Nuclear Medicine and the Society of Nuclear Medicine and Molecular Imaging (EANM/SNMMI) have detailed the preferred radiotracer choices for individuals with PPGL based on their genotype and/or clinical presentation, providing timely clarity in this rapidly moving field. The current review summarizes the implications of the genotype-phenotype relationship of PPGL, specifically relating this to the performance of molecular imaging modalities, to inform and enable practising endocrinologists to provide tailored, personalized care for individuals with PPGL.
