Introduction: Breast tumors such as cystosarcoma phylloides and fibroadenoma may show rapid growth and occur early in thelarche. In adolescents, tumor growth often remains unnoticed due to a lack of breast awareness or a sense of shame in these young girls. The necessity for surgical intervention may interfere with the normal development of the breast, however in certain cases has to be performed due to the threat of deformation of the growing breast or the malignant potential of some tumors like cystosarcoma phylloides. However, visible scars have to be avoided at any price in these young girls, as they are still in their pre-marital and psychologically vulnerable phase. The presumed size of the breast after completion of all Tanner stages of breast development has to be taken into consideration while planning the immediate or deferred reconstruction. Methods: We report on three young girls, 13, 14 and 16 years of age, who presented with a giant cystosarcoma phylloides of 9,6 cm (190 grams), a giant fibroadenoma of 14 cm (287 grams) and a giant PASH-tumor of 16,3 cm (957 grams). All patients were in their thelarche. The extension of the tumor was almost to the whole circumference of the breast with close borders to the skin envelope, resulting in a marked anisomastia due to the giant tumor size. We are proposing here scar-sparing procedures adapted to the form of the breast and the BMI of the patients. For access to the tumor, in two cases, we chose the anterior axillary line to avoid visible scars on the surface of the breast - one with autologous and one with heterologous, implant-based reconstruction. In the third case, the patient had a marked anisomastia with a massively ptotic breast with a huge broadening of the nipple-areolar-complex due to the growth of the tumor. Here we selected a tumor-size adapted, inferior-pedicled reduction mammaplasty according to Ribeiro in the modification of Rezai with a skin reduction and shortening of the diameter of the areola. Patient reported-outcome has been measured by validated Breast-Q-questionnaires. Results: We present three different types of access for the removal of giant tumors and three options for the reconstruction of patients in their thelarche. Two tumors were removed through axillary access to the breast to avoid scars in the developing breast. We achieved free margins at first surgical intervention in all three cases. One reconstruction was performed by autologous tissue through lateral thoracic wall advancement mammaplasty. Another patient had an implant-based reconstruction. The third patient – who presented with a macromastia with marked enlargement of the nipple-areola-complex was treated with a tumor-adapted reduction mammaplasty. All three young patients have reported a high degree of satisfaction in validated Breast QoL questionnaires with the outcome of the procedures.