Infantile myofibromatosis of orbital bone. A case report with computed tomography, magnetic resonance imaging, and histologic findings.

OBJECTIVE

The authors report the clinical, radiographic, histologic, and surgical findings of a rare presentation of infantile myofibromatosis. A mass presenting at the inferolateral orbital rim of a 4-year-old child was imaged with both computed tomography (CT) and magnetic resonance imaging (MRI), excised surgically and analyzed histologically to confirm the diagnosis. Infantile myofibromatosis is a rare benign disorder of childhood consisting of well-demarcated nonencapsulated tumors. The overall prognosis depends on the number and location of tumors. Isolated infantile myofibromatosis of the head and neck is the most common form of this generally benign disease.

DESIGN

A case review study is presented and discussed with regard to clinical, radiographic, histologic, and interventional findings. The literature is reviewed and the clinical relevance discussed.

INTERVENTION

Surgical extirpation of the tumor was undertaken after sufficient localizing radiographic information was obtained.

RESULTS

The tumor showed erosion of the orbital bone and orbital extension with reactive hyperostosis on CT imaging. The MRI finding showed an inhomogeneous well-demarcated dark mass on T1 images with increased signal intensity on T2 images. Gadolinium contrast showed significant vascular enhancement. Histologic sections showed a spindle-cell tumor of whorled myofibroblasts surrounding a hemangiopericytoma-like center. The tumor was excised completely. There has been no evidence of recurrence or adverse ocular sequelae in the first 6 months after surgery.

CONCLUSIONS

Cases involving the orbit or cranial bones are particularly rare but can have profound secondary effects on local structures. Isolated tumors can occur in all age groups and can mimic more aggressive or malignant neoplasms. The CT and MRI findings are beneficial in establishing a differential diagnosis, plan of treatment, and prognosis. Early diagnosis is important to rule out other neoplasms. The appropriate treatment is excisional biopsy whenever possible and is considered curative. The authors present what to our knowledge is the first reported case of an isolated infantile myofibroma involving an orbital bone.