Malignant Peripheral Nerve Sheath Tumor with Perineurial Differentiation, also known as malignant perineurioma, is related to leiomyosarcoma and fibrous histiocytoma. An important gene associated with Malignant Peripheral Nerve Sheath Tumor with Perineurial Differentiation is HTRA1 (HtrA Serine Peptidase 1), and among its related pathways/superpathways is Extracellular matrix organization. Affiliated tissues include pancreas.