Endogenous causes (with release of androgenic steroids)
(1) Cushing's syndrome (adrenocortical adenoma or carcinoma)
(2) pheochromocytoma
(3) masculinizing/virilizing ovarian tumor or androgen-secreting testicular tumor
(4) primary aldosteronism
Exogenous causes:
(1) androgen therapy
(2) androgen abuse by athletes
Diagnostic features:
(1) presence of an endocrine disorder or androgen therapy (usually with increased androgens in serum and/or urine)
(2) erythrocytosis that decreases on removal of the cause
(3) confidence in the diagnosis is further increased if there are no other causes for the erythrocytosis (secondary to hypoxemia, myeloproliferative disorder, erythropoietin therapy, erythropoietin secreting tumor)
Limitations:
• Diagnosis may be difficult in a patient with multiple possible causes (an athlete taking both androgens and erythropoietin, male with COPD and androgen therapy)
