Malignant phaeochromocytoma – a challenge in diagnosis and therapy

Phaeochromocytoma is an endocrine tumour that originates in catecholamine producing chromaffin cells of the adrenal medulla. Approximately 10% are malignant but there are no precise histological or biochemical markers to distinguish these from benign ones. The presence of metastases at distant sites is the most reliable clue but histologic features utilized in several scoring systems aid in predicting malignancy. Malignant phaeohromocytoma predominantly secrete noradrenaline and there may be high dopamine levels. Increased levels of chromogranin A, negative staining for inhibin/activin beta subunit and presence of SDHB mutation are the other factors associated with malignant potential. Multi modality evaluation with combination of CT, MRI, SPECT and radionuclide scintygraphy augments the diagnostic yield. Recent advance in molecular diagnostic markers further improved the knowledge in predicting malignant potential. Currently available therapeutic options are surgical debulking, pharmacological therapy for excess catecholamines, radionuclide therapy, antineoplastic therapy and external radiotherapy. These modalities provide symptomatic relief and biochemical control, but with no significant survival benefit. The development in the field of molecular pathway responsible for the malignant potential of phaeochromocytoma gives a hope to future therapy.DOI: http://dx.doi.org/10.4038/sjdem.v4i1.7253Sri Lanka Journal of Diabetes, Endocrinology and Metabolism 2014; 4: 40-42