[Intranodal myofibroblastoma: a case report].

INTRODUCTION: Myofibroblastomas are part of the heterogeneous group of myofibroblastic tumours, having first been described in 1989. They may be malignant or present a benign behaviour. Clinically they appear as a painless progressively growing mass in the soft tissue. CASE REPORT: A 12-year-old female teenager was referred to our hospital with a 1-year history of a painless growing mass in the inguinal region. A surgical excision was performed; its histological study revealed a proliferation of spindle cells arrayed in a fascicular pattern and with nuclear palisading, occupying the lymph nodes. Immunohistochemichal analysis demonstrated reactivity for vimentin, focally positive for CD34 and smooth muscle actin. She was then diagnosed with intranodal myofibroblastoma. Two years after the surgical excision there was a local recurrence followed by another resection. There have been no new recurrences 3 years after the second intervention. CONCLUSION: The intranodal myofibroblastoma is a rare benign mesenchymal neoplasm, without known pediatric cases and presenting differential diagnosis with other soft tissue tumours. Immunohistochemical studies are essential to establish its myofibroblastic nature.