Adrenal Cushing syndrome with detectable ACTH from an unexpected source.

Area of Science:

• Endocrinology
• Oncology

Background:

• Mixed corticomedullary adrenal tumours (MCMT) are exceptionally rare endocrine neoplasms.
• Adrenal masses require thorough biochemical evaluation due to potential for hormone overproduction.

Observation:

• A 48-year-old male presented with hypertension and Cushing syndrome, initially suggesting adrenal or ectopic ACTH-dependent Cushing syndrome.
• Initial biochemical tests showed elevated cortisol and ACTH, with normal plasma metanephrines.
• During attempted laparoscopic adrenalectomy, the patient experienced resistant hypertension, prompting repeat testing that revealed elevated plasma metanephrines.

Findings:

• Pathological examination confirmed a mixed corticomedullary adrenal tumour (MCMT).
• The patient's clinical course indicated coexisting Cushing syndrome and pheochromocytoma.
• Successful management involved α-blockade prior to adrenalectomy.

Implications:

• This case highlights the diagnostic challenge posed by MCMT, which can secrete multiple hormones.
• Emphasizes the critical importance of comprehensive biochemical screening for adrenal masses, including metanephrines, even with initial normal results.
• Suggests a potential for MCMT to present with concurrent hormonal syndromes, necessitating careful pre-operative assessment and management.