Massive osteolysis of skull bones secondary to lymphangioma of paranasal sinuses and mastoid sinus: report of two cases in children.

Massive osteolysis (MO) is a rare condition in which progressive localized bone tissue resorption is associated with proliferating thin-walled vessels in the absence of inflammation. Rare cases have been reported to occur in the skull. This paper describes two patients with MO who presented with massive assymetric swelling of the skull. This was associated with extensive enlargement of the paranasal sinuses (frontal, ethmoidal, and sphenoidal in one and the mastoid air cells in the other). The second patient developed subcutaneous emphysema on several occasions and the Valsalva maneuver increased the swelling, indicating transmission of the air from the nasopharynx to the mastoid cells and from there to the subcutaneous tissue. In the first patient, the sinus mucosa was shown to be involved by an extensive lymphangioma, and a similar change was seen in the mastoid air cells (patient 2). We are proposing that MO of these two patients resulted from bone resorption due to progressive extension of sinus mucous lymphangiomata.