Cisti del rafe mediano del pene [Median raphe cyst of the penis. Report of a case]

Median raphe cysts are uncommon lesions occurring in the midline male perineum, usually the ventral penis. However, lesions may be found anywhere between the urinary meatus and the anus. Clinically the cysts usually present as single and asymptomatic papules with whitish transparent contents. They are most commonly recognized during the first three decades of life. Etiology is unknown, but many investigators believe that they represent a defect in the embryologic development of the male genitalia. Histologically the lesions derived from the distal portion of the urethra (of ectodermal origin) reveal the presence of an epithelium that is stratified and squamous (mucoid cysts) while those that develop from the rest of the urethra (of endodermal origin) show a pseudostratified and columnar epithelium (nonmucinous cysts). In some cases the lesion may be present from birth and tends to remain as a cavity until filled in response to a stimulus, most often a trauma or a bacterial infection. The case of a 36-year-old patient with a median raphe cyst located in the ventral penis that became evident following a bacterial infection by Streptococcus faecalis is described.