Myopericytoma is a perivascular myoid neoplasm of skin and soft tissues characterized by numerous thin-walled blood vessels surrounded concentrically by round to spindle myoid tumor cells, which shows α-smooth muscle actin and h-caldesmon coexpression and commonly negativity for desmin. These tumors arise predominantly in extremities of adult patients with benign clinical course. Based on the architectural pattern, there are various histologic variants as classical-solid myopericytoma, hemangiopericytoma-like myopericytoma, angioleiomyoma-like myopericytoma, myofibroma-like myopericytoma, hipocelular fibroma-like myopericytoma, intravascular myopericytoma, cellular immature myopericytoma, and malignant myopericytoma. The authors report a case that fully satisfies the morphological and immunohistochemical criteria for intravascular myopericytoma, which plantar location is not previously described in the literature. In addition, the authors discuss about its possible development from a preexistent cutaneous vascular malformation.
BackgroundMelanoma of the anal region is a very uncommon disease, accounting for only 0.2-0.3% of all melanoma cases. Mutations of the BRAF gene are usually absent in melanomas occurring in this region as well as in other sun-protected regions. The development of a tumour in a longstanding perianal fistula is also extremely rare. More frequent is the case of a tumour presenting as a fistula, that is, the fistula being a consequence of the cancerous process, although we have found only two cases of fistula-generating melanomas reported in the literature.Case PresentationHere we report the case of a 38-year-old male who presented with a perianal fistula of four years of evolution. Histopathological examination of the fistulous tract confirmed the presence of malignant melanoma. Due to the small size and the central location of the melanoma inside the fistulous tract, we believe the melanoma reported here developed in the epithelium of the fistula once the latter was already formed. Resected sentinel lymph nodes were negative and the patient, after going through a wide local excision, remains disease-free nine years after diagnosis. DNA obtained from melanoma tissue was analysed by automated direct sequencing and the V600E (T1799A) mutation was detected in exon 15 of the BRAF gene.ConclusionSince fistulae experience persistent inflammation, the fact that this melanoma harbours a BRAF mutation strengthens the view that oxidative stress caused by inflammatory processes plays an important role in the genesis of BRAF gene mutations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.