Pericardial diverticula misdiagnosed as pericardial cysts

Abstract

Pericardial cysts, which result from complete closure of an embryonic pericardial defect, are believed to occur at a frequency of 1 in 100,000, based on a 1958 chest radiograph screening. 1 Surgery is routinely not recommended, unless obvious compression of adjacent organs is demonstrated. However, 10% of all cysts may be instead a pericardial diverticulum with a persistent connection to the pericardial space, not apparent from radiologic studies, and identified only at surgery. 2 These lesions may cause atypical symptoms that are relieved only after surgery, as demonstrated by this case report. CASE REPORT A 66-year-old retired biologist was diagnosed in 1984 with an ''enlarged fat pad,'' by chest radiograph. Chest computed tomography (CT) scans revealed a right, cardiophrenic, 2.5-cm, soft-tissue cystic mass that had increased to 7.3 cm by 2008 (Figure 1). Additional studies included:

Current concepts of diagnosis and management of pericardial cysts

“…Although radiologically a lesion may appear to be a pericardial cyst, in 10% of the time, it is actually a diverticulum 18 . Although dissimilar on anatomical basis, both pericardial cyst and diverticula are considered as a sequelae of common embryogenesis going wrong and are usually discussed together by most embryologists 18, 19, 20, 21, 22, 23, 24. Pericardial cysts and diverticula usually arise due to herniation through a structural defect in the pericardium 19, 20.…”

“…Rohn et al first described similar origin of both the lesions and concluded that the pericardial cyst probably is a remnant of a diverticulum whose communication to the pericardial cavity has been obliterated 23 . To assure that it is truly a “cyst”, it might be necessary to trace the communicating channels during dissection of the pericardial cysts and if found be ligated to prevent a diverticulum from reoccurring 18 . Pericardial diverticula may be congenital or acquired.…”

“…Congenital cases may result from a failure in the fusion of one of the mesenchymal lacunae that normally combine to form the pericardial sac. Acquired pericardial diverticula may be due to sequelae of pericardial diseases and effusion 18, 19, 20, 21, 22…”

“…These symptoms may not correlate with activity. Nocturnal symptoms may be gravity dependent, possibly due to a shift of the fluid from the pericardium back into the pericardial sac, potentially causing a tamponade effect affecting venous return 18 . Mazer 28 first described this fluid shift in 1946 and Money reported a case with a pericardial diverticulum that had been misdiagnosed for 30 years as a cyst, wherein intermittent nocturnal symptoms resolved after surgical removal 18 …”

“…Such chest discomfort is position and gravity dependent and arising due to gravity dependent fluid shift between the pericardial sac and the cyst cavity. This fluid accumulation in the pericardial sac causes a tamponade like effect thereby obstructing venous return 18 . Mazer 28 first described this fluid shift in 1946 and Money 18 has been attributed in successfully explaining the causes for these gravity dependent drainage of pericardial fluid leading to the positional symptoms in patients with pericardial diverticulum.…”