[Angiomatoid malignant fibrous histiocytoma. Clinico-pathologic and immunohistochemical study of a case]

The results of a clinico-pathologic and immunohistochemical study of an angiomatoid malignant fibrous histiocytoma are reported. This lesion is an uncommon tumor of the superficial soft tissue, of low-grade malignancy, typical of adolescence and early adult life. The patient, a 10-year-old female, presented with a mass of the left popliteal fossa, treated with surgical excision of the tumor and the surrounding cutaneous and subcutaneous tissue. The tumor was a well-circumscribed, firm nodule measuring 2.5 x 1.0 cm. Histologically, it showed aggregates of spindled and rounded cells often lining cystic cavities filled with blood. The immunohistochemical analysis revealed a cytoplasmatic immunoreactivity for KP1 (CD68), which was taken as indicating that the tumoral mesenchymal cells had acquired phagocytic capacities. The patient is well without signs of local recurrence or metastatic disease 4 years after the surgical treatment. The case reported confirms that appropriate local surgery is the elective therapy for this type of soft tissue tumor.