The Great Imitator

The Great Imitator (also The Great Masquerader) is a phrase used for medical conditions that feature nonspecific symptoms and may be confused with a number of other diseases. Most great imitators are systemic in nature. Diseases sometimes referred to with this name include:

• Various cancers
  • Intravascular large B-cell lymphoma
  • Mycosis Fungoides
• Beriberi
• Various rheumatic conditions, including:
  • Fibromyalgia
  • Psoriatic arthritis
  • Lupus erythematosus
    • Systemic lupus erythematosus
  • Sarcoidosis
• Multiple sclerosis
• Celiac disease
• Addison's disease
• Pulmonary embolism
• Various infectious diseases, including:
  • Syphilis
  • Lyme disease
  • Nocardiosis
  • Tuberculosis
  • Brucellosis
  • Infective endocarditis
  • Malaria
• Breathing-related sleep disorders (chiefly sleep apnea/hypopnea and upper-airway resistance syndrome)
• Hypoglycemia as an imitator of a stroke
• Amyloidosis
• Pheochromocytoma
• Various abdominal conditions:
  • Appendicitis
  • Pancreatitis