PCOS remains a diagnosis of exclusion: a concise review of key endocrinopathies to exclude.

Polycystic ovarian syndrome (PCOS) is a heterogenous disorder associated with clinical, endocrine and ultrasonographic features that can also be encountered in a number of other diseases. It has traditionally been suggested that prolactin excess, enzymatic steroidogenic abnormalities and thyroid disorders need to be excluded before a diagnosis of PCOS is made. However, there is paucity of data regarding the prevalence of PCOS phenotype in some of these disorders, whereas other endocrine diseases that exhibit PCOS-like features may elude diagnosis and proper management if not considered. This article reviews the data of currently included entities that exhibit a PCOS phenotype and those that potentially need to be looked for, and attempts to identify specific features that distinguish them from idiopathic PCOS.