Poster Presentation ESA-SRB 2023 in conjunction with ENSA

Mr KC, a 14-year-old Year 9 student, presented to the Emergency department with a six-day history of new onset headaches and transient visual blurring. He had a past medical history of renal stones (with normal genitourinary tract anatomy on imaging) and anxiety.       .

An MRI scan showed a 2.1cm pituitary lesion with local mass effect and minimal compression of the optic chiasm. The pre-operative pituitary panel showed elevated gonadotrophin levels, FSH 29.8 IU/L (1.2 – 5.2 IU/L) and LH 8.8 IU/L (2.0 – 8.0 IU/L), with a testosterone level of 10.9 nmol/L (0.7 – 17.6 nmol/L). Remainder of anterior pituitary function was normal.

On examination, he was tanner stage P4 G4, testicular volumes 5-6ml (right) and 6-8ml (left) with expected volumes of 15-20ml at this Tanner stage¹. There was no history of cryptorchidism. Height was 175cm (75th centile) and weight 60.1kg (63rd centile). He started undergoing puberty at the age of 12.

He underwent transsphenoidal resection (TSS) of the pituitary lesion. Intraoperatively, appearances were suggestive of a craniopharyngioma adherent to the pituitary stalk, necessitating transection of stalk to achieve complete resection. Post-operatively, the patient developed AVP-deficiency, hypocortisolism and secondary hypothyroidism requiring replacement with desmopressin, hydrocortisone and levothyroxine. The histopathology of the lesion was suggestive of a Rathke’s cleft cyst. 

Karyotype testing confirmed a 47 XXY genotype, consistent with Klinefelter syndrome. Repeat assessment of gonadotrophin levels revealed low FSH and LH levels with an undetectable testosterone level, consistent with post-TSS hypogonadotrophic hypogonadism superimposed on a background of primary hypogonadism.  He was commenced on testosterone replacement therapy. Our patient’s case highlights the importance of careful history taking and physical examination, particularly a thorough assessment of pubertal development and testicular examination. The presence of small testes in conjunction with evidence of hypergonadotrophic hypogonadism on hormonal assessment, should trigger further assessment with karyotype².