ESPE Abstracts

A 4.9-year-old girl presented with a 6-month history of excessive body odour and suspected breast development. Family history was significant for presence of Lynch syndrome in both her father and paternal grandmother. At presentation, she was pre-pubertal but tall for her age. Her height was 124 cm (SDS 3.5), and weight was 27.1 kg (SDS 2.69). Her height velocity was accelerated at 15 cm/year and bone age was advanced at 7 years. Investigations revealed an elevated IGF-1 (500 mg/L NR 35 – 232), IGFBP3 (7.1 mg/dl NR 1.9 – 5.2) and GH secretion failed to suppress on oral glucose tolerance test (OGTT). LHRH test revealed a prepubertal response. Prolactin, thyroid and cortisol levels were within normal limits. Contrast MRI revealed a pituitary micro-adenoma measuring approximately 3∗7∗8 cm confirming the diagnosis of Pituitary gigantism. At 5.66 years of age, she underwent an intra -operative MRI-guided trans-sphenoidal excision of her microadenoma. Histology confirmed a neuroendocrine tumour with widespread expression of growth hormone and little expression of prolactin. Two months post-surgery, her height velocity and IGF-1 level declined to 9 cm/year and 390 ng/L respectively. She did not develop any other pituitary hormone deficiencies. However, five months post-surgery, IGF-1 started to increase again, suggesting incomplete resection/recurrence. Growth hormone secretion failed to suppress on a repeat OGTT. Contrast MRI scan revealed a 4 mm area of hypo-enhancement in the anterior pituitary gland. A 11C-Methionine PET scan co-registered with volumetric MRI brain scan confirmed presence of a small residual adenoma in the pituitary gland. She has been started on Pegvisomant and her IGF-1 is showing a downward trend. She is planned to have a repeat MRI scan at 6 months after starting Pegvisomant to re-assess tumour growth and need for repeat surgery. Her R217 gene panel has been reported to be normal. The results of X-linked acro-gigantism genetic test are awaited. At present, her parents are reluctant for her to undergo genetic testing for Lynch syndrome. Corticotroph and prolactin secreting adenomas have been reported in adults with Lynch syndrome, hence the discussions regarding the importance of having this genetic test are ongoing with the family. The family have to choose between long-term Pegvisomant therapy (provided her tumour remains under control) or have a repeat surgery with a high-risk of developing pituitary hormone deficiencies subsequently. This case highlights challenges as well as recent developments in management of paediatric Somatotropinomas.