Cushing disease is a genetic disease characterised by hypersecretion of adrenocorticotropic hormone (ACTH) by pituitary tumors that are resistant to glucocorticoid negative feedback. The pituitary tumors generate a range of clinical traits of chronic hypercortisolism such as, obesity, hypertension, hirsutism, cutaneous striae, diabetes mellitus, muscle loss, psychosis, menstrual irregularity, widened face with acne, and fatigue. ACTH is produced as a precursor from the POMC gene product. Microadenomas in Cushing's disease are identified through magnetic resonance imaging (MRI) and mandatory pre-operative localization of pituitary adenomas is performed through trans-sphenoid microsurgical method.
Pituitary Adenoma 4, ACTH-Secreting (Cushing Disease, Pituitary) is associated with mutations in USP8 gene.
Gupta et al. (1998) analyzed the sensitivity of computed tomography (CT) and magnetic resonance imaging (MRI) of the pituitary gland in identifying pituitary adenomas in 25 subjects aged 8-55 years and suffering from Cushing's disease. MRI revealed that 16 of the 25 subjects had adenomas, of those 12 were found to be microadenomas and 4 macroadenomas. The authors colcuded that the favored tool for identifying ACTH-secreting adenomas was contrast-enhanced MRI rather than CT scans due to the small size of the adenomas.
[Gupta R, Gambhir M, Ammini AC. Imaging of the pituitary gland in Cushing's disease. Med Principles Pract. 1998; 7:246-50.]