Lympho-monocytic enteroviral myocarditis: traditional, immunohistological and molecularpathological methods for diagnosis in a case of suspected sudden infant death syndrome (SIDS)

A 7-month-old boy was found lifeless in his bed by his grandfather. Near the mouth there were some blood and chyme on the bedlinen. His mother reported a chill during the last 8 days. Autopsy revealed multiple petechia under the capsule of the thymus, subepicardially and subpleurally, the cause of death was tentative supposed to be a sudden infant death. Histologically parts of the myocardium showed a lympho-monocytic myocarditis according to the DALLAS-criteria. Immunohistological investigations demonstrated an enhanced expression of MHC class II antigens, an increased number of leucocytes as well as T-lymphocytes. In situ hybridization and immunohistochemistry revealed myocardial enterovirus infection. Considering that there were regions in the myocardium without the traditional findings of myocardial necrosis and inflammation but with distinct expression of the above mentioned immunohistologic markers, immunohistological investigations turn out to be an appropriate tool to examine infant fatalities with uncertain cause of death for early stages of myocarditis.