A seat comprising a back support portion (100) with adjustable surface profile, comprising an adjustable core column (101) arranged along the height direction of the back support portion (100) and comprising a plurality of holders (110, 210, 211, 310, 410) and a plurality of side members (120, 220, 221, 320, 420) fixed to the holders (110, 210, 211, 310, 410) and extending substantially in the width direction of the back support portion (100) such as to profile the surface of the back support portion (100). It further comprises profile locking means (130) coupled with a plurality of holders (110, 210, 211, 310, 410) and adjustable to an unlocked configuration, in which the holders (110, 210, 211, 310, 410) are individually rotatable around a plurality of axes and the profile of the surface of the back support portion (100) is adjustable and to a locked configuration, in which the holders (110, 210, 211, 310, 410) are fixed still with respect to each other and the profile of the surface of the back support portion (100) is locked.
