A 30 year old female is diagnosed with clinical MEN-2a based on bilateral pheochromocytoma and metastatic medullary thyroid cancer (MTC). She presented with a two-year history of panic attacks, associated with headache, vomiting, hand paraesthesia and a sensation of neck constriction. Fourteen months prior, she had an uneventful pregnancy and normal vaginal delivery. The panic attacks progressively worsened post-partum, and now occurred on a daily basis. She was previously diagnosed with post-partum thyroiditis on thyroxine replacement; there was no family history of malignancy. Clinical examination revealed a normotensive woman without marfanoid features or mucosal neuromas. She had a non-tender goitre and a right neck lump.
Plasma metanephrines were significantly elevated (normetanephrines >9999pmol/L (normal <900), metanephrines 2375pmol/L (normal <500)); chromogranin A was 167pg/L (normal <85); calcitonin was 173pmol/L (normal <61pmol/L). Calcium and parathyroid levels were normal.
Whole body CT showed a 4.5 × 3.5cm right adrenal mass (40 Hounsfield units), multiple hepatic and osseous lesions, an enlarged goitre and marked cervical lymphadenopathy, the largest being 2.4 × 1.6cm with central necrosis. Fine-needle aspirate revealed abnormal cells with positive staining for calcitonin and chromogranin, suggestive of MTC. Imaging with MIBG scan revealed uptake in the large right adrenal mass and also a 1cm left adrenal mass consistent with bilateral phaeochromocytomas. In contrast, the hepatic, osseous and cervical nodal lesions were FDG-PET and Ga-68 DOTANOC PET avid, but not MIBG-avid, consistent with metastatic MTC.
The patient was commenced on phenoxybenzamine and underwent an uncomplicated laparoscopic right adrenalectomy and total thyroidectomy. Histology confirmed MTC and phaeochromocytoma. The small left adrenal pheochromocytoma remains insitu.
Options for systemic therapy with tyrosine kinase inhibitors are currently being explored as the optimal management for metastatic MTC is unknown. Genetic testing for RET proto-oncogene, SDHB and SDHD mutations have been undertaken. RET proto-oncogene mutation has not been detected and this needs to be further explored.