Endocrine Abstracts

Background: Acinic cell carcinoma of the parotid gland is a rare cancer, and metastatic (M1) disease is uncommon, occurring in around 10% of cases, with ectopic paraneoplastic Cushing being described in only few cases.

Clinical case: A 58-year-old woman, with a history of dedifferentiated parotid acinar cell carcinoma, underwent surgery and adjuvant radiotherapy in 2005. In February 2019 the disease recurred with pulmonary, bone and lymph node metastases. Despite further 4 lines-oriented chemotherapies disease showed liver progression. April 2022, facial edema, asthenia, muscle weakness, skin fragility and hyperpigmentation and worsening of blood pressure control with abdominal obesity and hypokalemia established. Clinical suspicion of ACTH dependent Cushing’s syndrome was confirmed by the biochemical studies: ACTH 1174pg/ml, plasma cortisol 59 mg/dl, urinary free cortisol (UFC) 2046 mg/24h (1633 mg/24h by mass spectrometry), 8 mg dexamethasone test: cortisol: 27 mg/dl. Pituitary MRI was negative for adenoma and 68Ga-DOTATE- PET scan was positive for all M1, suggesting positive somatostatin receptors. PET-FDG showed similar distribution of the radiotracer. Biopsy of the new liver M1 shows a high-grade carcinoma, Ki80%, and a positive ACTH in 10%, as well as positive expression of somatostatin receptors 2 and 5. Treatment of the hypercortisolism with the steroid inhibitor Osilodrostat was started in rapidly ascending doses to 10mg c/12h, with rapid and stable decrease of cortisol at basal values of 26 mg/dl with a UFC of 416 mg/24 h after 4 weeks of treatment with control of hypertension and of the Cushing phenotype. K and oedema were controlled by adding mineralocorticoid antagonists. Two doses of PRRT with Lu177-DOTATATE were administrated at external center with significant reduction of the liver M1. Intercurrence of urinary sepsis with hypotension in context of self-overdosing of analgesic treatment required parenteral glucocorticoid administration, and finally block and replace treatment was selected (UFC at hospital discharge was of 268 mg/24 h with cortisol of 7 mg/dl y under concomitant dexamethasone 2 mg/day). Unfortunately, despite biochemical stability during 3 months of Osildrostat and partial response to the PRRT the clinical condition acutely worsted due to spinal cord compression and palliative treatment was initiated.

Conclusion: Hereby we show the clinical case and therapeutic approach of a salivary carcinoma with metastatic late recurrency after more than one decade with ectopic ACTH secretion.