Occult Ectopic Adrenocorticotropic Hormone Secretion: Diagnostic Dilemma and Infective Consequence

A 42-year-old male presented with polyuria, polydipsia and weight loss. His initial physical exam showed a paucity of cushingoid features. Diagnostic work up was consistent with an ectopic adrenocorticotropic hormone (ACTH) secretion. Imaging studies showed a small anterior mediastinal lesion without additional metabolically active tumors. Fine needle aspiration was consistent with a thymic neuroendocrine tumor. Following radical thymectomy, plasma ACTH and cortisol levels remained elevated. Despite medical management, he died within 2 months of presentation of disseminated intracranial aspergillosis. This case underscores the diagnostic dilemma of occult ectopic ACTH-secreting tumors and the fatal consequence of opportunistic infections.