Salient Observations from Clinical Profile and Long-Term Outcome of a Cohort of Patients with Ectopic Cushing's Syndrome.

INTRODUCTION

Ectopic adrenocorticotropic hormone (ACTH)/corticotropin-releasing hormone production by tumours causes 5-10% of Cushing's syndrome cases. We present a 21-patient case series with ectopic Cushing's syndrome (ECS) from a tertiary care institute in India.

METHODS

Data were collected retrospectively for patients from 1984 to 2004 and prospectively thereafter till 2019. This included clinical signs, diagnostic tests, comorbidities, imaging, management, outcomes, and follow-up data.

RESULTS

In this study of 21 patients (14 males, mean age 32.4 ± 14 years) diagnosed with ECS, the mean lag period between the symptom onset and diagnosis was 15.9 ± 11.9 months. Predominant symptoms were proximal muscle weakness (85.7%), menstrual irregularity (85.7% of females), hyperpigmentation (76.2%), weight gain (61.9%), and infections (23.8%). Key signs included cuticular atrophy (100%), easy bruising (95.2%), and striae (71.4%). Despite 33.3% losing weight, 61.3% gained. 71.4% of the patients experienced diabetes, and 90.5% had hypertension as their metabolic complications. All patients exhibited disrupted cortisol circadian rhythms. The mean cortisol level at 0800 h was 1220 ± 556.2 nmol/L, while at 2300 h, it was 1108.3 ± 491.7 nmol/L. The median 0800-hour ACTH was 139 pg/ml. 22.2% displayed a paradoxical increase in morning cortisol post-high-dose dexamethasone suppression test. Thymic carcinoid is as prevalent as bronchial carcinoid in ECS causation.

CONCLUSION

ECS is rare, but it is crucial to distinguish it from Cushing's disease, as tumour removal is the preferred treatment. In Cushing's syndrome evaluations, ECS should always be considered since no single test is definitive for its diagnosis.