This is a sign of premature balding that's frequently seen in men. What's this kind of hair distribution called (it's a German word)? It can also be seen in women. What could then be the underlying cause? I'll post the correct answer in a few days!
Correct answer: This typical type of hair distribution is called 'Geheimratsecken'. When seen in women, it can be a sign of virilisation (e.g. due to hormone therapies or adrenal malfunction).