Abstract: SA-PO1007

Double Trouble with Small Cell Lung Cancer: A Case of Simultaneous Production of Two Ectopic Hormones from a Common Lung Primary

Session Information

Category: Nephrology Education

  • 1302 Fellows and Residents Case Reports

Author

  • Agarwal, Krishna A., UMMS-Baystate, Chicopee, Massachusetts, United States
Background

The association of small cell lung cancers (SCLC) with syndrome of inappropriate antidiuretic hormone secretion (SIADH) is well known. Upto 15% cases with SCLC exhibit SIADH but only 1% of patients with SCLC have ectopic ACTH production.

Methods

A 55-year-old cachectic woman with recurrent hospitalizations for weakness, nausea and vomiting was seen in the nephrology office for hyponatremia. SIADH was diagnosed on bloodwork and CT scan of her chest revealed a new hilar mass. Bronchoscopic biopsy and metastatic workup confirmed a small cell type lung cancer with metastasis to her liver, right femur and ribs. Her hyponatremia was treated with water restriction and salt tablets. Two weeks later, she was admitted with right lung collapse and found to have persistent hypertension, metabolic alkalosis, hyponatremia and hypokalemia alongwith elevated ACTH and cortisol. A high-dose overnight dexamethasone suppression test revealed an ectopic non-suppressible source of ACTH and imaging studies ruled out a pituitary or adrenal source of hypercortisolemia. Repeat chest CT showed extensive local infiltration of the lung cancer and widespread hepatic metastasis. Palliative chemotherapy and ketoconazole were trialed in the hopes of reducing tumor burden and improving hypercortisolemia but her clinical status continued to deteriorate and she passed away peacefully.

Results

Case studies have shown that upto 15% of SCLC patients have SIADH and management of hyponatremia improves mortality and therefore palliative chemotherapy is recommended even for extensive disease. Our patient had a unique presentation with both hyponatremia and hypercortisolemia. The median survival time of patients with extensive SCLC is 6-12 months, but it decreases to 7.1 months with concomitant hyponatremia and to 5.5-6.2 months with ectopic ACTH production.

Conclusion

There have only been rare case reports of multiple ectopic hormones being produced from a single primary SCLC. Due to the poor prognosis associated with extensive lung cancer disease and significant worsening with paraneoplastic phenomena like SIADH and ACTH, it is important to diagnose these conditions early and initiate aggressive treatment. Especially, chemotherapy and treatment of hyponatremia because these have been shown to improve performance status and mortality.