Acquired smooth-muscle hamartoma of the scrotum: a histological simulator?

Background:

In three cases of chronic scrotal lymphedema, histological and immunohistochemical changes were observed that were strikingly similar to an exceedingly rare lesion reported previously under the name of acquired smooth-muscle hamartoma (ASMH) of the scrotum. The clinical context indicated that the cases were reactive rather than hamartomatous in nature.

Materials and methods:

The histological and immunohistochemical findings of the three cases were compared to macroscopically normal scrotal specimens obtained during sex reassignment surgery in seven male-to-female transsexuals.

Results:

Compared to the seven controls, the three cases of chronic scrotal edema revealed a marked increase of dartos smooth-muscle tissue and of connective tissue of the scrotal skin and underlying soft tissues. Still, even the normal amount of scrotal smooth-muscle tissue may easily be misinterpreted as smooth-muscle hyperplasia.

Conclusions:

Chronic scrotal lymphedema may induce hyperplasia of the dartos muscle, resulting in a histological appearance previously described as ASMH. This indicates that ASMH may not always represent a later onset of abnormality similar to congenital smooth-muscle hamartoma but, rather, may constitute a histological simulator.