Possible participation of isolated epicardial cell clusters in the formation of chick embryonic epicardium

The embryonic epicardium is formed by the spreading of cells derived from the extracardiac proepicardial organ over the myocardial surface after transfer to the dorsal side of the myocardium via a bridge of villous projections. Using whole-heart immunostaining for keratin, we found that the chronology and pattern of epicardial formation in the chick was basically identical to that reported previously in the quail. However, discrete epicardial islands were observed on the ventrolateral surface of the atrioventricular canal as well as in two previously reported areas. Closer examination by scanning electron microscopy demonstrated the presence of isolated, sparsely distributed epicardial cell clusters on both the dorsal and ventral surfaces of the myocardium. These cells showed a surface morphology similar to that of the epicardial cells at the advancing edge of the spreading epicardial sheet and possessed numerous well-developed filopodia, suggesting active motility. These clusters are probably seeded onto the myocardium by vesicular transport from proepicardial villi, and our findings suggest that the resulting small, localised patches of epicardial cells might accelerate, supplement and tune the epicardial formation mediated by radial spreading of the epicardial sheet in the chick embryonic heart.     

Rare incidence of three consecutive primary tumors in the maxillofacial region: retinoblastoma, leiomyosarcoma, and choriocarcinoma: case report

Multiple primary tumors occur more commonly in the region of the head and neck than elsewhere in the body. The chance of this is particularly high in patients treated for retinoblastoma, in part because of a genetic predisposition, and in part because of the possibility of irradiation treatment. However, triple tumors occur in only 0.5% of multiple tumors. A rare case of a triple (metachronous) tumor is reported: 12 years after the treatment of bilateral retinoblastoma (enucleation and irradiation), secondary leiomyosarcoma developed in the maxillofacial region, followed 5 years later by choriocarcinoma. Surgery was performed on all three types of tumor. As a result, the female patient (currently 21 years old) is now free of complaints and has married. It is extremely rare for either leiomyosarcoma or choriocarcinoma (CHC) to appear in the maxillofacial region. The long-term, systematic control of such patients is absolutely necessary, for the multiple tumors tend to develop only after a long latency period of 10 to 20 years.     

Oral cancer: a self-assessment quiz

This article consists of a quiz on oral cancer knowledge. The goals of the quiz are to reinforce known cancer information and present new information. Photographs are used to bring a sense of the practical problems that clinical pathology presents. Also, a number of real-life case situations are presented with their corresponding illustrations so that the readers may use their clinical judgment and experience in choosing an answer.