Primary adenocarcinoma of the lung with a synchronous carcinoid tumour of the small intestine
A 55-year-old man with known chronic obstructive pulmonary disease, hypertension and a 40-pack-a-year smoking history, presented to the cardiology clinic with exertional dyspnoea. Examination revealed a raised jugular venous pressure, systolic murmur and peripheral oedema. Severe tricuspid regurgitation was confirmed on echocardiogram. Spirometry showed an FEV1 of 41%.\nFive years later he was referred to the colorectal surgeons with a two-year history of intermittent diarrhoea 6–7 times per day, two stone weight loss and a 5 cm craggy liver edge. He denied flushing or night sweats.\nA computed tomography (CT) scan of the thorax/abdomen was performed showing widespread adenopathy above and below the diaphragm. A new 2 cm mass in the anterior segment of left upper lung lobe was identified (Figure a). These images were considered consistent with a diagnosis of primary lung cancer or lymphoma; however, the abdominal pattern on the CT scan was not typical of lung carcinoma. Separate retro-peritoneal lymph node and transthoracic lung biopsies were therefore performed under CT guidance.\nThe retroperitoneal lymph node biopsy showed a metastatic carcinoid, positive for synaptophysin and chromogranin but negative for CK7, TTF1 and CK20 and CD 56 (Figures a and b). The left upper lobe lesion biopsy showed a completely different pathology: an invasive non-small-cell lung adenocarcinoma, positive for CK7 and TTF1, consistent with a lung primary (Figures c and d). It also demonstrated positivity for synaptophysin, showing a degree of neuroendocrine differentiation but was negative for CD56. These findings suggested two separate malignancies.\nThe lung adenocarcinoma was staged with a positron emission tomography scan showing high-grade metabolic activity in the lung lesion and intermediate metabolic activity in the retroperitoneal nodes.\nThe synchronous presence of a carcinoid tumour was further demonstrated by significantly raised levels of 5-hydroxyindoleacetic acid (over 13 times the upper limit of normal). An octreotide scan, used to differentiate the carcinoid tumour from other tissues, showed positive enhancement in a large mesenteric mass (Figure d) not seen on the CT scan (Figure c) and, was somatostatin receptor negative in the lung lesion (Figure b). This provided further evidence of two separate pathologies.\nThe lung adenocarcinoma was staged at T1N0M0. It was not appropriate for surgical resection due to the patient's severe tricuspid regurgitation, not the stage of the adenocarcinoma. Radical radiotherapy, 55 Gy in 20 fractions to the lung, was performed.\nAs the carcinoid tumour was considered metastatic, most likely originating from the small bowel, octreotide was given to provide relief for diarrhoea. The patient was referred to a Carcinoid Centre where long acting octreotide was commenced.