Rationale:Lymphangiomas develop in the head, neck, and axilla of patients <2 years old in more than 90% of cases. They are rarely reported in adults.Patient concerns:Here, we report on a 37-year-old woman with a firm, hypoechoic 3.3 cm mass in the right upper, outer quadrant of the breast with discomfort, and swelling of the right axillary region.Diagnosis and interventions:She underwent wide excision of the right breast and axillary lesion and the lesion pathologic finding is lymphangioma of the breast.Outcomes:She was in good condition with no signs of postoperative complications and no evidence of recurrence at 6 months postsurgery.Lessons:Despite the rarity of breast cystic lymphangioma, its evaluation should be considered for prompt diagnosis and definitive treatment to prevent recurrence and complications. Furthermore, this is the first case of concomitant lymphangioma of the breast parenchyma and axillary region.