title: [Congenital myofibroma. A true hemangiopericytoma. A neonatal case with immunohistochemical and ultrastructural studies].
abstract: We report the case of a male newborn infant with a pedunculated dermic tumor, located in the right malar region; who underwent a complete surgical resection of the tumor and had a satisfactory postoperative evolution. The histopathologic findings disclosed a subcutaneous tumor with a nodular aspect and a subendothelial intravascular growth, constituted by a dual population of small cells and spindle-shaped cells, distributed in a biphasic pattern. All tumor cells showed a strong pericellular reaction for PAS. The immunohistochemical studies revealed: diffuse cytoplasmic positivity for CD34 and Vimentin in all tumor cells, and only spindle-shaped tumor cells and less differentiated isolated neoplastic cells, presented cytoplasmic positivity for the smooth muscle alpha-actin. The electronic microscopy demonstrated a layer of basal membrane and in the citoplasm, numerous intermediate filaments with focal condensations. Based on all these findings, we conclude that this is a myofibroma, a "true hemangiopericytoma" with myofibroblastic differentiation. For this reason, we propose the term myofibropericytoma, in order to highlight its pericytic origin and its myofibroblastic differentiation. We emphasize the need to recognize this entity, in view of its low frequency and the possibility of a diagnostic mistake with other soft tissues tumors that display haemangiopericytoma-like features.
authors.affiliation: Servicio de Cirugía Pediátrica, Maternidad Concepción Palacios y Cátedra de Anatomía Normal, Escuela de Medicina Luis Razetti, Facultad de Medicina, Universidad Central de Venezuela. trejoscorza@gmail.com
authors.forename: Ezequiel
authors.initials: E
authors.lastname: Trejo-Scorza
authors.forename: María Isabel
authors.initials: MI
authors.lastname: Viña-Ramírez
authors.forename: Norma
authors.initials: N
authors.lastname: Oviedo-Ayala
authors.forename: Alipio Antonio
authors.initials: AA
authors.lastname: Hernández-Faraco
authors.forename: Jesús María
authors.initials: JM
authors.lastname: Alvarado-Sanavria
authors.forename: Simón
authors.initials: S
authors.lastname: Paz-Ivanov
mesh_terms: D002454:Cell Differentiation; D002610:Cheek; D005153:Facial Neoplasms / Q000737:chemistry / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D006393:Hemangiopericytoma / Q000737:chemistry / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D047708:Myofibroma / Q000737:chemistry / Q000145:classification / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D009363:Neoplasm Proteins / Q000032:analysis; D040521:Subcutaneous Tissue; D009626:Terminology as Topic; D014057:Tomography, X-Ray Computed
chemical_list: D009363:Neoplasm Proteins