Lymphangioma and its variants are benign congenital malformations. We present an atypical case of a cystic hygroma of the chest wall in a 10 month old child. The child came with a painless progressive swelling in left lateral chest wall. Examination revealed a swelling of 7 x 5 cm along the left anterior axillary line from third to seventh intercostals spaces, ovoid in shape, mobile, tense but painless. Ultrasonogram revealed a cystic lesion in left chest wall. MRI showed a well defined cystic lesion with septations in the subcutaneous plane with intermuscular extensions favouring a lymphangioma. Surgical excision of the cyst was performed. Histopathology revealed as lymphatic cyst (macrocystic variant of lymphangioma).