Cervicothoracic cystic lymphangiomas are rare benign tumors developing from sequestration of embryonic lymph sac which is gradually filled with lymph fluid. The diagnosis is based on clinical signs (laterocervical swelling) and imaging (ultrasound and CT scan), then confirmed by histology after surgery which constitutes the basis of treatment. We here report a case of cervicothoracic cystic lymphangioma and review of the literature