Endocrine cells in median raphe cysts of the penis

Serotonin-storing cells are distributed in all tissues derived from cloaca. They were observed in the cavernous portion of penile urethra whereas they were absent from the glans portion. Serotonin cells were detected in several morphologic varieties of median raphe cysts. It is suggested that these cysts arise from the endodermal part of urethra.