Endocrine Abstracts

Phaeochromocytomas are rare neuroendocrine tumours. Prediction of aggressive tumour behaviour remains a major challenge. We report a 68-year-old female who was found to have a locally arising colonic adenocarcinoma on biopsies. Staging also identified a 10.7 cm right adrenal lesion and work-up revealed markedly raised urinary metanephrines and positive MIBG imaging. The MDT decision was to first remove the colonic cancer with appropriate alpha blockade. It was felt that a combined laparoscopic approach would not be appropriate given the size of the adrenal lesion, which might require an open procedure. Histology confirmed a stage III Duke’s C tumour and adjuvant chemotherapy was commenced. Although adrenal surgery had been planned once she completed chemotherapy, she did not tolerate chemotherapy and it had to be discontinued. An open adrenalectomy was finally undertaken. Histology was consistent with a phaeochromocytoma with a PASS score of eight. Two months after adrenal surgery, she reported intermittent tingling and numbness in the left arm with intermittent thoracic back pain. An MRI confirmed a soft tissue mass at T2 extending into the spinal cord. Urinary metanephrines confirmed persistently elevated normetadrenaline levels. She underwent bilateral laminectomy followed by spinal radiotherapy. Histology confirmed a metastatic phaeochromocytoma. Post-operative Ga⁶⁸-DOTATATE PET-CT has since revealed DOTATATE avid lung and mediastinal lymph node metastases. Further systemic treatment of this metastatic phaeochromocytoma has been delayed as a frontal brain lesion has now been identified, which is not DOTATATE avid, and likely represents a low-grade glioma; a craniotomy is planned. Treatment with ¹⁷⁷Lu-DOTATATE is being considered following surgery. The management of malignant phaeochromocytomas remains challenging. Radical resection of the primary and metastatic tumours is the treatment of choice. High-dose iodine (131)-MIBG therapy can be used to treat unresectable metastatic disease when MIBG-positive lesions are present. Chemotherapy has been associated with symptomatic improvement and external beam radiation is being used to provide local tumour control or to treat symptoms of local invasion. Peptide receptor radioligand therapy with ¹⁷⁷Lu-DOTATATE and/or ⁹⁰Y-DOTA-TOC has shown encouraging results in small case series and offers an exciting new method in the management of inoperative or metastatic phaeochromocytomas.