MRI of the Hypothalamus and Pituitary Gland in Patients with Hyperprolactinaemia Following Radiotherapy for Nasopharyngeal Carcinoma

KY Lau, WT Fung, PO Chan, WM Sze, AWM Lee, TK Yau
Correspondence: Dr K Y Lau, drkylau@yahoo.com

ABSTRACT
Purpose Neuroendocrine dysfunction is a known complication of cranial radiation. While growth hormone deficiency is the most common laboratory finding, hyperprolactinaemia is one of the most common symptomatic dysfunction in adult female patients with nasopharyngeal carcinoma (NPC) following radiotherapy. This analysis aims to study the magnetic resonance imaging (MRI) features of the hypothalamus and the pituitary gland in affected patients.
Methods MRI was performed in 24 patients NPC with hyperprolactinaemia detected 10-52 months following one course of radical radiotherapy. The region of study included the nasopharynx, the hypothalamus and the pituitary gland in 20 patients, while in the remaining four patients, this was limited to the pituitary gland. The estimated radiation dose to the hypothalamus and the pituitary gland was 66 Gy, and six patients also had adjuvant chemotherapy. There was no clinical evidence of tumour recurrence in all 24 patients when hyperprolactinaemia was detected.
Results None of the 24 patients showed any MRI evidence of structural abnormality in the hypothalamic-pituitary region.
Conclusion MRI did not reveal any structural abnormality in the hypothalamic-pituitary region of patients who developed hyperprolactinaemia following radiotherapy for NPC.

Keywords: Magnetic resonance imaging, Nasopharyngeal carcinoma, Hyperprolactinaemia, Radiation-induced complication
Singapore Med J 2001; 42(9): 406-409