Ectopic ACTH syndrome in lung carcinoids – a case series

S. Ribeiro*^a (Dr), T. Moreno^a (Dr), A. Varela^a (Dr), P. Freitas^a (Prof), D. Carvalho^a (Prof)

^a Faculty of Medicine, Centro Hospitalar Universitário São João, Porto, PORTUGAL

* saravmribeiro@gmail.com

Ectopic ACTH secretion accounts for 10-20% of endogenous Cushing’s syndrome (CS). More often its source is located to the lung, associated with highly malignant tumours or with less aggressive variants of neuroendocrine tumours, carcinoid tumours. Here we present a case series of 6 ectopic Cushing in the context of lung carcinoids.

The 6 patients ranged in age from 38 to 75 years (median 45,5y) and included 2 men and 4 women. All but one (case 6) had cushingoid features; lower leg edema was present in 5/6 of the cases. Hypokalemia was present in 3/6 cases, whereas de novo diabetes and hypertension were a feature in 5/6 and 4/6, respectively. ACTH levels ranged from 105.7 - 698 ng/L favoring ACTH-dependent CS. Results of bilateral inferior petrosal sinus sampling confirming ectopic origin of ACTH was performed in 4/6 cases. High dose dexamethasone suppression test suggested EAS for patient 5 and 6.

Duration of symptom onset to diagnosis of CS ranged from 3 to 36 months (median 5 mo), whereas lag time between CS diagnosis and tumor localization ranged from 6 to 60 months (median 9 mo). Tumor size ranged from 8 to 33 mm. Case 6 had a diagnosis of DIPNECH. Four out of 6 cases were histologically classified as typical carcinoid; one (case 1) as atypical carcinoid. In the remaining case (case 6), distinction was not possible because surgery was not performed. One of patients (case 3) required bilateral adrenalectomy for uncontrolled CS with refractory hypokalemia and respiratory infections. All but one of the patients (case 6) had no evidence of metastasis at time of diagnosis and were subjected to surgery. Case 6 had imagiological evidence of disseminated metastasis and was started on octreotide, which she maintains at 12 months of follow-up. A second patient (case 4) had evidence of metastasis 9 months following surgery. He did 25 months of lanreotide therapy before switching to everolimus due to evidence of disease progression. The remaining patients are disease free (follow up range 24-168 months).

In this work we will review clinical features at presentation, strains in tumour location and response to therapy.

The author has declared no conflict of interest.