Congenital-infantile fibrosarcoma: Study of two cases and review of the literature

BACKGROUND: Congenital-infantile fibrosarcoma is a rare tumor of the pediatric age. It involves subjects under 5 years of age, and more than 200 cases have been reported in the literature. METHODS: The authors present the clinicopathologic findings of 2 cases and review the literature. RESULTS: Of our 2 patients, the first was a 2-years and 6-months-old female and the second a newborn male. The female presented a tumor in the retroperitoneum without recurrences or metastasis after 17 months, and the male on left foor with a recurrence after 3 months. Histologically, the tumors were mainly composed of spindle-shaped cells. Immunohistochemically, in both cases, neoplastic cells were positive for vimentin; focal positivity for muscular specific actin was present in the tumor of the female. Ultrastructurally, tumors were composed of mesenchymal cells with fibroblastic and myofibroblastic features. Flow cytometric analysis of the retroperitoneal tumor showed an aneuploid population of neoplastic cells. CONCLUSIONS: Congenital-infantile fibrosarcoma should be considered a borderline tumor; its biologic behavior is better than that of adult fibrosarcoma. Histologic diagnosis is not easy; the microscopic picture may be confused with fibromatosis or with malignant mesenchymal neoplasms. Only a follow-up of many years can confirm the benignancy or malignancy of any individual tumor, even though clinico-pathologic features may be distinctive enough to permit its recognition.