Intramyocardial bronchogenic cyst: histological appearance and a review of the literature.
We report histological appearance of a bronchogenic cyst that was incidentally found in a 78-year-old man who died from drowning related to a traumatic accident. The cyst was found in the posterior edge of the interventricular septum and was monolocular with a 5-mm diameter. The cystic wall was not associated with cartilage or the smooth muscle layer, and was lined by ciliated respiratory epithelium. Immunohistochemistry showed that many of these epithelial cells were positive for cytokeratin 7 and thyroid transcription factor-1. A few of the cells were positive for CA19-9, chromogranin A, synaptophysin, and S-100. No cells were positive for cytokeratin 20, p63, bcl-2 and napsin A. This feature was compatible with bronchogenic cyst, and is not common compared with previously reported immunohistochemical features of cystic tumors of the atrioventricular node. A low prevalence of p53, single strand-DNA, and Ki-67 indicated modest cell turnover in the epithelial cells of present case. Our survey of the English literature showed 23 cases of intramyocardial bronchogenic cyst. Although asymptomatic cases were dominant in the literature, some intramyocardial bronchogenic cysts showed life-threatening arrhythmia, which could cause sudden unexpected death.