A lymphangioma is a rare congenital malformation of the lymphatic system. An axillary cystic lymphangioma in an adult patient has rarely been presented. A 32-year-old male patient was admitted with swelling under his left armpit that persisted for approximately two months. During his physical examination, a left axillary, 12×10 cm, mobile, well-circumscribed, smooth, painless mass was detected. The patient had a history of allergic asthma. During his axillary ultrasound examination, 36 mm and 120×65 mm anechoic reactive lymphadenopathies, including thinwalled cystic lesion multiple septations and magnetic resonance imaging of the thorax, the left axillary region by the 12×6×4.5 cm lobular contour revealed a septal cystic mass. Histopathologic examination of the fluid aspiration revealed hemosiderin-laden macrophages, lymphocytes, and ground proteinaceous material. Intraoperative left arm given4 cc of methylene blue subcutaneously to the inner face and mass was painted blue. Total excision was performed. A histopathological examination revealed a cystic lymphangioma. After surgery, the patient did not develop complications or recurrence in the follow-up for 30 months. Eighty percent of cystic lymphangiomas are seen in the posterior neck. They are often asymptomatic. Ultrasonography, computed tomography, magnetic resonance imaging, and biopsy are performed. Ultrasonography revealed multiloculated cysts . The extent of tumor computed tomography and lymphatic cystic renatured understandable. Magnetic resonance imaging with the mass limits and can be viewed in relation to the surrounding tissue. However, a definitive diagnosis is made by histologically examining the masses. Treatment is by surgical excision. After surgical excision, the prognosis is quite good. There have been local recurrence in a few cases, and fistulas and infections have also occurred. A lymphangioma is a benign tumor. It is seen usually in infants and during childhood. Radiology help, though definitive diagnosis is made by histopathologic examination. Treatment is by surgical excision.

Keywords: Adult, axilla cystic, lymphangioma