Neonatal disorders
-Influx of maternal hormones through the placenta
-Mastitis neonatorum (infection)
Breast abscesses.
Benign premature thelarche (isolated breast development in females aged 6 months to 9 years)
Precocious puberty
Intraductal papillomas,
Phyllodes tumors,
Primary breast cancer (rare)
Metastatic lesions (rare)
Further Reading
Semin Plast Surg. 2013 Feb; 27(1): 19–22. Management of Pediatric and Adolescent Breast Masses. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3706046/