Role of immunohistochemical and histochemical profiling in H&E-based diagnosis of scrotal leiomyosarcoma of dartos muscle.

ABSTRACT

Histochemical and immunohistochemical methods should often but not always complement standardized histopathologic procedures. Here, we illustrate use of these ancillary techniques in a report of scrotal leiomyosarcoma. 62-year-old male patient presented with a palpable, subcutaneous 2,5 cm wide tumor arising from dartos muscle. The tumor was diagnosed leiomyosarcoma G2 pT1b. Interestingly, the sarcomatous mass was focally strictly attached to convoluted, benign bundles of smooth muscles that were intermingled with tumor mass at peripheral, lateral and superior sides of the lesion. We have used immune- and histochemical methods to confirm histopathological findings based on H&E staining. As expected, in tumor cells smooth muscle actin and desmin were strongly immunopositive similarly as Masson trichrome staining, while S100 and CD34 antigens were immunonegative except for sustained positivity for CD34 in vessels. The auxiliary staining methods can provide additional information on the tumorigenesis of leiomyosarcoma. They can also serve to determine additional features of prognostic significance, since e.g. immunoreactivity of CD34 accurately maps vascular density of tumor and enables a careful assessment of vascular invasion in course of leiomyosarcoma as well.