Pediatric myofibroma/myofibromatosis of the soft tissue and bone: a clinicopathological analysis of 28 cases / 中华病理学杂志

Objective: To investigate the clinicopathological features, diagnosis and differential diagnosis of pediatric myofibroma/myofibromatosis of the soft tissue and bone. Methods: All cases of pediatric myofibroma/myofibromatosis of the soft tissue and bone diagnosed between January 2011 and December 2018 were retrieved from the surgical pathology records in the Department of Pathology, Beijing Jishuitan Hospital, Beijing, China. Clinical and radiological data were collected. H&E and immunohistochemistry were used to examine histological and immunophenotypic features and to make the diagnosis and differential diagnosis. The relevant literature was also reviewed. Results: Twenty-eight cases of pediatric myofibroma/myofibromatosis of the soft tissue and bone were respectively collected. The patients' ages ranged from 2 months to 14 years, with a mean age of 7 years. There were 7 females and 21 males. There were 12 cases located in soft tissue, including the finger (n=9), upper arm (n=1) and foot (n=2). There were 14 cases located in the bone of limb, including the femur (n=8), tibia (n=4), clavicle (n=2), fibula (n=2) and radius (n=1). There were 2 cases of myofibromatosis involving multiple bones. Radiology showed lytic lesions in the bone. The proliferation of spindle-shaped myofibroblasts arranged in fascicles with indistinct eosinophilic cytoplasm and bland nuclei, with no pleomorphism and cytological atypia. The characteristic histologic structure was the biphasic nodular growth pattern with cellular and paucicellular regions. The tumors might arrange in a hemangiopericytoma-like pattern. The stroma varied between dense fibrosis and myxoid changes. The reactive new bone formation and inflammatory cell infiltration also existed. Immunohistochemical study showed that the SMA was positive. The surgical resections were performed. One of the patients had tumor recurrence as a result of 11-month follow-up. Conclusions: The pediatric myofibroma/myofibromatosis of the soft tissue and bone is a very rare benign tumor and has a good prognosis. It has a characteristic morphology and its differential diagnosis from other spindle cell tumors could be made with the immunohistochemical analysis.

Miofibromatosis infantil / Infantile myofibromatosis

La miofibromatosis infantil es una enfermedad del período neonatal o de la infancia temprana; consiste en la aparición de uno o múltiples tumores fibrosos que afectan piel, tejido celular subcutáneo, músculos, huesos y/o vísceras. Son tumores con tendencia a la involución espontánea, y su pronóstico está condicionad por la presencia o no de compromiso visceral. Se presenta el caso de un recién nacido de 48 horas de vida, con una tumoración en miembro superior derecho, sin compromiso visceral, que presentó involución espontánea en un plazo de 8 meses.

Infantile myofibromatosis is an illness of the neonatal period or early childhood. It consists of the appearance of one or more fibrous tumors which affect the skin, subcutaneous tissue, muscles, bones and/or viscera. These tumors tend to undergo spontaneousinvolution, and the prognosis is conditioned by the presence or absence of visceral liability. The case of a 48-hour newborn is described. The infant presented a tumour in the upper right member, which did not revealedvisceral liability and which resulted in spontaneous involution over an eight month span.

Miofibromatose congênita: relato de caso / Congenital miofibromatose: case report

Os autores apresentam um caso de miofibromatose congênita, cursando com tumoração em região escapular direita e comprometimento ósseo. O diagnóstico foi sugerido por exames de imagem: radiografia do esqueleto e ressonância nuclear magnética, e confirmado pelo estudo histopatológico da lesão. Por ser uma doença rara os autores fazem uma revisão bibliográfica, descrevendo aspectos de apresentação e evolução clínica da doença, avaliação diagnóstica, e abordagem terapêutica