A tuberous breast, also known as tubular breast, is one specific variety of breast hypoplasia, in which insufficient breast tissue develops in certain areas of the breast. Typically, the lower half is underdeveloped compared with the upper half. The breast base, which is the measurement of the width of the breast at the chest wall, is small and the nipple areolar complex (the nipple and the darker colored skin around the nipple) is widened and looks unnatural compared with the overall shape and size of the breast.
The fold under the breast tends to be at a higher position, and the breasts tend to be widely spaced apart. The breast grows forwards and droops downwards, with a lack of fullness to the breast. The cause for this is unknown and it can affect only one of the two breasts, with the other developing normally. Correction of tuberous breasts involves both increasing the overall size of the breast, and correcting the construction in the lower half to allow the breast to widen and develop a full and natural shape.