Giant Phyllodes Tumor in Ectopic Breast Tissue

Breast masses are uncommon in children and adolescents. Ectopic breast tissue is further uncommon and may be present in locations such as the face, back, and thigh. A 12-year-old female child presented with a hard, nonmobile lump in the right breast. On exploration by submammary incision, the lump was found to be below the pectoralis major muscle and had no communication with the overlying orthotopic breast tissue. Histopathological examination revealed a well-encapsulated biphasic lesion, with features characteristic of a phyllodes tumor. We report a hitherto unreported case of aberrant breast tissue lying under the pectoralis muscle and containing phyllodes tumor.