Endocrine Abstracts

Section 1: Case history: A sixty-three-year-old Caucasian male presented with a six-week history of lethargy, emotional lability, polydipsia, polyuria, increased appetite and weight gain. He also reported changes in his facial features and widening of the gaps between his teeth. He has a background of hypertension, obstructive sleep apnoea and benign prostatic hyperplasia. On examination, the patient appeared plethoric, had coarsened facial features, mild prognathism and evidence of easy bruising.

Section 2: Investigations: Initial investigations revealed hypokalaemia of 2.4 mmol/l, HbA1c of 54 mmol/mol and a chest X-ray which showed a rounded lesion near the right heart border. Baseline morning cortisol was 664 nmol/l and an overnight 1 mg dexamethasone suppression test failed to suppress cortisol at 625 mmol/l. ACTH was 49 ng/l. IGF-1 was 287 mcg/l. Growth hormone day curve measured as follows: 1.8 mcg/l (08:30), 2.15 mcg/l (11:00), 2.85 mcg/l (13:00), 2.19 mcg/l (17:00), 1.34 mcg/l (19:00). Growth hormone releasing hormone levels of 248 ng/l (0–59 ng/l). CT thorax showed a 54 mm solid, highly vascular lesion at the right cardiophrenic angle with several right lower lobe nodules and a solitary 11 mm middle mediastinal node. The large 54 mm lesion was also FDG and Galinium-68 DOTATATE avid, indicating somatostatin receptor positivity. CT adrenals revealed bilateral adrenal hyperplasia and MRI pituitary was unremarkable.

Section 3: Results and treatment: Clinical presentation and investigations suggested ectopic ACTH/GHRH production likely from the right lung nodule. He was initially managed with an etomidate infusion followed by metyrapone. A trial of octreotide did not show any improvement in his cortisol day curve. He was discharged with metyrapone 500 mg, 750 mg and 750 mg. The patient proceeded to surgical management and underwent a right middle lobe and right lower lobe wedge resection with mediastinal lymph node dissection. Post operatively, cortisol level was 305 nmol/l and ACTH was 10 ng/l, and he was started empirically on hydrocortisone 10 mg, 5 mg, 5 mg. Pathology from surgical resection revealed a 55 mm typical carcinoid tumour with a Ki-67 of 1–2% and a 9 mm typical carcinoid tumour with a Ki-67 of 30%. The lymph nodes were negative for metastases. Immunohistochemistry for ACTH was negative in both tumours. There were multiple foci of neuroendocrine hyperplasia in the background lung which raises the possibility of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH).

Section 4: Conclusions and points for discussion: Diagnosis is GHRH & ACTH secreting pulmonary neuroendocrine tumour and DIPNECH.

Points for discussion

– Management of DIPNECH

– Negative staining for ACTH on histology

– Follow up management