Myopericytoma/myopericytomatosis of the lower extremity in two young patients: a recently designated rare soft tissue neoplasm

Abstract

Myopericytomas are rare, slow-growing benign perivascular tumors most commonly arising within the superficial subcutaneous soft tissues of the lower extremity. They represent one of several related perivascular tumors of myoid lineage with similar morphology and shared immunohistochemical profile including positive staining for smooth muscle actin. Histologically, myopericytoma exhibit concentric, perivascular proliferation of spindled myoid cells with bland elongated nuclei and associated blood vessels. A solitary well-demarcated nodule or mass is typically referred to as myopericytoma, whereas an infiltrative multinodular lesion has more recently been termed myopericytomatosis. At magnetic resonance imaging, tumors are most commonly superficial, may be well-defined (myopericytoma) or ill-defined (myopericytomatosis), and demonstrate highly vascularized, avidly enhancing soft tissue often with areas of internal hemorrhage. We report 2 cases involving the lower extremity (1 myopericytoma and 1 myopericytomatosis) occurring in young patients, focusing on the clinical, histopathologic, and radiologic characteristics of this relatively new distinct entity.

Myopericytoma in right inguinal region: A rare case report from Nepal

“…Diagnostic imaging of this patient did not corroborate with the findings that are anticipated in cases of myopericytoma as these tumors are typically well-defined, homogenous, and highly vascular [ 9 ]. The imaging findings of this patient are more consistent with that of myopericytomatosis, in which diagnostic imaging reveals a more heterogenous mass with ill-defined swelling [ 9 ]. Although immunohistochemical tests were not performed, one would normally expect a positive stain for MSA (muscle specific actin), SMA (smooth muscle actin), and h-caldesmon in myopericytoma cells.…”

Myopericytomatosis of the Foot: a Case Report Including Molecular Identification of a PDGFRB Mutation

“…In 2017, Hung and Fletcher reported a series of eleven cases of diffuse dermal and/or subcutaneous involvement of myopericytomatous nodules identified out of a collective of over 1000 surgically treated myopericytic lesions [3]. Beyond that, we identified only one more case in current worldwide literature [4]. Clinically, the predilected localization is the lower extremity as seen in eleven of the twelve formerly described patients.…”

Single Nuclear RNA Sequencing Highlights Intra-Tumoral Heterogeneity and Tumor Microenvironment Complexity in Testicular Embryonic Rhabdomyosarcoma

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