Bronchopulmonary carcinoid with a single lymph node metastasis causing ectopic Cushing's syndrome

Area of Science:

• Endocrinology
• Oncology
• Pulmonology

Background:

• Bronchial carcinoid tumors (BCTs) are neuroendocrine tumors of the lung.
• They can secrete neuropeptides, including ACTH, leading to Cushing's syndrome (CS).
• Typical BCTs rarely metastasize, and only a small percentage of CS cases are caused by BCTs.

Observation:

• A patient presented with ectopic CS.
• The cause was identified as a typical BCT that had metastasized to a lymph node.
• This is an uncommon presentation, as typical BCTs rarely metastasize.

Findings:

• Ectopic ACTH secretion from a typical BCT can occur.
• Metastasis from a typical BCT, though rare, is possible.
• ACTH secretion may indicate a more aggressive tumor subtype.

Implications:

• Diagnostic workups for CS should be comprehensive.
• Ectopic ACTH-secreting BCTs should be considered in the differential diagnosis of CS.
• The findings suggest a correlation between ACTH secretion and tumor aggressiveness in typical BCTs.