Generalized infantile myofibromatosis with a monophasic primitive pattern

Area of Science:

• Pediatric Pathology
• Developmental Biology
• Oncology

Background:

• Infantile myofibromatosis (IM) is a rare congenital tumor characterized by a biphasic histological pattern.
• Generalized IM can involve multiple organs, posing significant diagnostic and therapeutic challenges.

Observation:

• A case of neonatal-onset generalized IM with extensive visceral and placental involvement is presented.
• The lesions exhibited a monophasic histological pattern of primitive mesenchymal cells with a hemangiopericytoma-like vascular structure.
• Immunohistochemical and ultrastructural studies confirmed primitive cell features without mature myofibroblastic differentiation.

Findings:

• No ETV6-NTRK3 or ACTB-GLI fusion genes were identified in the tumor cells.
• The patient experienced cerebral hemorrhage and respiratory failure, leading to death at four months of age.
• The monophasic primitive histological pattern in generalized IM correlated with a poor clinical outcome.

Implications:

• This case highlights a potential variant of generalized IM with a distinct histological presentation and poor prognosis.
• Further research into the genetic and molecular underpinnings of monophasic IM is warranted.
• Understanding this variant may aid in early diagnosis and the development of targeted therapies for infantile myofibromatosis.