Pericardial Celomic Cysts

Abstract

In the presidential address before the Twenty-Third Annual Meeting of the American Association for Thoracic Surgery at Cleveland in 1940, Lambert (1) spoke on “The Etiology of Thin-Walled Thoracic Cysts.” Although his discussion was based on only four cases, two from the literature (2, 3) and two which had been reported to him by other surgeons (F.B. Berry and E.F. Butler), his explanation and name for this type of mediastinal cyst has been accepted without dissent. An excellent review of cysts and cystic tumors of the mediastinum is that of Laipply (4). He listed eight kinds of congenital cysts: epidermoid, dermoid, teratoid, bronchial, esophageal, gastro-enteric and pericardial celomic cysts, and cystic lymphangioma. Only the last two, which are of purely mesodermal origin, will be considered here. These differ considerably in gross and histologic morphology. The cystic lymphangiomas have a complicated structure; they are multilocular and the cyst walls are of varying thickness. Sections of one such specimen (5) showed hyaline fibrous tissue with scattered clusters of fat cells, foci of lymphocytes, blood vessels, areas of smooth muscle fibers, and cystic spaces of various sizes lined with a single layer of flattened endothelium. As Lambert pointed out, the lymphangiomas are intimately incorporated with the surrounding structures, they receive their blood supply from all sides, and cannot be shelled out. Attempts at removal are often associated with severe hemorrhage. The infiltration gives the impression that they are of neoplastic origin. They may occur in any region of the thorax and elsewhere in the body. On the other hand, those cysts which Lambert has named “pericardial celomic cysts” are simple in structure. They are usually unilocular and are lined with a thin layer of mesothelium, which peels readily from the surrounding structures. The contained fluid is clear or sanguineous. The four cysts previously described and the one reported here have been adjacent to the pericardium. Lambert's explanation for these cysts is based on a consideration of the embryology of the pericardium. This structure arises from a series of disconnected lacunae which appear early in the life of the embryo. These lacunae in the mesenchyme remain for a time as individual spaces, but eventually coalesce to form the pericardial celom. If one of these lacunar cavities failed to merge, it could persist and give rise to a cyst in the vicinity of the pericardium, a pericardial celomic cyst. Since only four cases have been reported, they can be reviewed briefly. Dufour and Mourrut (2) published the autopsy findings in a woman who died at the age of eightysix years of cerebral softening. In the anterior mediastinum, in relation to the superior part of the pericardium, was a cyst containing 120 c.c. of reddish.fluid, It was called a “lymphatic cyst.”