Quote from "Pediatric Surgery (Springer Surgery Atlas)" by Prem Puri, Michael E. Höllwarth -
"The breast tissue present in gynecomastia is most often tender, firm, and subareolar. One third of boys will present with unilateral gynecomastia. A mass in the breast that is not subareolar and is asymmetric should raise concern for other conditions. A testicular exam is a key component of the physical exam to rule out hypogonadism, suggestive of Klinefelter’s syndrome, a varicocele, or possible estrogen-secreting tumors of the testes, such as germ cell tumors, Sertoli cell tumors, or Leydig cell tumors."
"The breast tissue present in gynecomastia is most often tender, firm, and subareolar. One third of boys will present with unilateral gynecomastia. A mass in the breast that is not subareolar and is asymmetric should raise concern for other conditions. A testicular exam is a key component of the physical exam to rule out hypogonadism, suggestive of Klinefelter’s syndrome, a varicocele, or possible estrogen-secreting tumors of the testes, such as germ cell tumors, Sertoli cell tumors, or Leydig cell tumors."