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Solitary infantile myofibromatosis in the femur

T Yamamoto1, K Mizuno, K Hanioka

  • 1Departments of Orthopedic Surgery and; Pathology, Kobe University, Kobe, Japan. yamatetu@med.kobe-u.ac.jp

Pathology International
|May 3, 2000
PubMed

Insights

This case study details a rare solitary infantile myofibromatosis in an infant's femur. The benign tumor presented as an osteolytic lesion, confirmed by pathological and immunohistochemical analysis.

Area of Science:

  • Pediatric Oncology
  • Skeletal Pathology
  • Soft Tissue Tumors

Background:

  • Infantile myofibromatosis is a rare benign tumor affecting infants.
  • The solitary type typically presents as a single lesion.
  • Long bone involvement is uncommon, especially in the diaphyseal region.

Observation:

  • A case of solitary infantile myofibromatosis involving the right femur in an 11-month-old female is presented.
  • Radiographic imaging revealed a well-defined osteolytic lesion in the femoral diaphysis.
  • Pathological examination showed spindle-shaped cells with eosinophilic cytoplasm, fascicular arrangement, and cleft-shaped vascular spaces.

Findings:

  • Immunohistochemical staining confirmed tumor cell reactivity for vimentin, alpha-smooth muscle actin, and desmin.
  • Ultrastructural analysis identified numerous thin and intermediate filaments within the tumor cell cytoplasm.
  • This represents the third reported instance of solitary infantile myofibromatosis specifically affecting long bones.

Implications:

  • This case contributes to the limited literature on infantile myofibromatosis of long bones.
  • Accurate diagnosis through imaging, pathology, and immunohistochemistry is crucial for appropriate management.
  • Understanding the cellular and ultrastructural characteristics aids in differentiating this benign entity from other bone lesions.

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