Although very variable, the phenotypic features of PCOS can be schematically divided into three components, i.e., hyperandrogenic, anovulatory and dysmetabolic. These three components are not necessarily or fully associated.

Hyperandrogenism
Usually, symptoms are moderate and consist of increased male-pattern hair growth, acne, seborrhea or alopecia, which reflect mild androgenic stimulation of the pilosebaceous unit. Hyperandrogenism symptoms frequently commence at the time of puberty. In some cases, hyperandrogenism is expressed before puberty as ‘precocious adrenarche’ in patients who subsequently develop PCOS, indicating an early adrenal involvement.

Anovulation
This component of PCOS accounts for oligomenorrhea (i.e. menstrual cycle length >3 months) and secondary amenorrhea, which are the most typical features of the anovulatory PCOS. They very often date back to menarche. Primary amenorrhea is uncommon, but PCOS is still found in about 20% of girls referred for this symptom. These patients have no pubertal delay and are frequently overweight. The amenorrhea is quite reversible under short sequences of progestin treatment, without having to add estrogens. This qualifies this amenorrhea as ‘normoestrogenic’ or ‘type 2 anovulation’ in the World Health Organization (WHO) classification. About 20% of adolescent and adult patients with PCOS report normal menses. However, this does not mean necessarily that they ovulate each cycle. In a recent study, 20% of them were in fact anovulatory.

Metabolic Syndrome
Obesity (i.e., BMI >25 kg/m²) is observed in 30 - 50% of adolescent and adult women with PCOS.

Most women with PCOS become overweight just before or during puberty and several lines of evidence suggest that the onset of obesity in this period of life could represent a specific risk factor for the subsequent development of PCOS. Obesity of women with PCOS is frequently characterized by a distribution of fat that favors the upper body segment (increased WHR). This type of fat distribution is detected even in adolescent girls with normal BMI and is associated with greater insulin resistance than if fat is located predominantly in the lower body segment. Papular hypertrophic pigmented skin on the nape of the neck, the axillae, chest and vulva is detected in 5 - 50% of women with PCOS. This dermal manifestation, acanthosis nigricans, is now recognized as a non-specific marker of moderate to severe insulin resistance.