Ectopic ACTH Production Caused by Metastatic Parotid Gland Acinic Cell Carcinoma

Abstract

Objective: To present a case of adrenocorticotropic hormone (ACTH) hypersecretion caused by a metastatic acinic cell carcinoma (AcCC) of the parotid. Only 6 cases have been reported prior to October 2019. We believe that this condition is under-reported and hope that improved recognition will improve its reporting. Methods: Diagnosis in this case was done using surgical pathology of the primary tumor, involving lymph nodes, and a metastatic lesion. Following an initial misdiagnosis, a final diagnosis of AcCC was made using immunohistochemical staining. ACTH hypersecretion was diagnosed by testing for random ACTH, cortisol, and 24-hour urine aldosterone and cortisol levels. Results: A 57-year-old man presented with hypokalemia, lower-extremity edema, and left-side rib pain 7 months following excision of a 4-cm left-parotid tumor. Immunostaining positive for DOG-1, CK7, pancytokeratin (including CAM5.2), and SOX10 led to the diagnosis of AcCC. ACTH hypersecretion was diagnosed based on a random ACTH level of 307 pg/mL (normal morning value, 7.2-63 pg/mL), a cortisol level of 33 mg/dL (normal morning value, 4.3-19.8 mg/dL; normal PM value, 3.1-15.0 mg/dL), a 24-hour urine aldosterone level of <0.7 U (normal, 2.0-20 U), and a 24-hour urine cortisol level of 4564 U (normal, 3.5-45 U). The patient's ACTH hypersecretion and hypokalemia were treated with potassium replacement, amiloride, and ketoconazole. His metastatic recurrence was treated with radiotherapy, chemotherapy, and immunotherapy. The patient died after being diagnosed with sepsis secondary to multifocal postobstructive pneumonia 4 months after the diagnosis of his metastatic recurrence. Conclusion: Ectopic ACTH production caused by metastatic AcCC is a rare phenomenon but has been increasingly described over the last 15 years. We believe that this condition likely has a greater prevalence than what is reported and that improved recognition will lead to improved outcomes.

ACTH-secreting parotid acinic cell carcinoma unusually reported as a paraneoplastic syndrome

“…There is only one case of a primary acinic cell carcinoma secreting ACTH (Castro Oliveira et al 2019). In cases where long-term follow-up has been performed, patients suffered from disease complications and died despite being treated with chemotherapy and/or radiation therapy (Shenoy et al 2011;Dacruz et al 2016;Castro Oliveira et al 2019;Wade et al 2020;Burch et al 2021).…”