We report on two cases of an unusual but distinctive variant of lymphangiomatosis, presenting at birth with predominantly cutaneous involvement of the body wall and complicated by chylothorax. The lesion manifested clinically as a slowly progressive, diffuse, and fluctuant skin swelling. Eventually, almost the entire trunk became affected. There were no bone lesions. Histologically, the soft tissues were diffusely infiltrated by interconnecting mazelike lymphatic vessels. The two infants died from infection at the age of 23 days and 10 months, respectively. Our experience confirms that premortem histologic diagnosis of lymphangiomatosis is difficult to establish. Awareness of the condition and knowledge of its various clinical presentation forms are essential for proper recognition, assessment of the outcome, and evaluation of new therapeutic measures such as interferon.