Case: A 54-year-old man underwent a partial resection for a thymic carcinoid in 2008 followed by radiotherapy. He was subsequently found to carry the MEN1 gene mutation. His other manifestations of MEN 1 included primary hyperparathyroidism, a growth hormone-secreting pituitary adenoma, neuroendocrine tumours of the pancreas and liver and a gastrinoma. Due to ongoing tumour progression, he was treated with capecitabine and temozolamide in 2019. In 2020, he presented with worsening dysphagia and superior vena cava obstruction due to local tumour compression. He was admitted to hospital and treated with dexamethasone and palliative radiotherapy to the mediastinum. He experienced hypoglycaemia associated with high C-peptide, insulin and proinsulin levels, raising the suspicion of a proinsulin-secreting insulinoma. This was initially treated with cornstarch and diazoxide, but the diazoxide was switched to octreotide due to oedema. In line with his wishes for second-line palliative chemotherapy, he was commenced on carboplatin and etoposide. Although he tolerated his second cycle of chemotherapy poorly, necessitating an admission to the palliative care unit for presumed end-of-life care, he made a remarkable recovery, and repeat imaging has demonstrated stable disease nine months later.
Discussion: We present the case of a complex patient with thymic carcinoid occurring in the context of many concurrent manifestations of MEN 1. This case illustrates the difficulties of treating thymic carcinoid given its aggressive nature. There is a limited evidence base to guide therapeutic options, which include surgical resection, radiotherapy and adjuvant chemotherapy. More investigational treatments include somatostatin analogues, peptide receptor radionuclide therapy and everolimus. However, despite this and multiple other manifestations of MEN 1, this patient has demonstrated meaningful progression-free survival.