Angiomatoid fibrous histiocytoma with pain in a child.

Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue tumor with low-grade malignancy which occurs chiefly in children and young adults. Mostly, the tumor develops in the extremities or the trunk. The tumor has a relatively rare metastasis and its overall clinical outcome is excellent. The authors present a case of AFH of the subcutis on a left elbow of an 11-year-old boy. Clinically, the tumor appears as a cutaneous nodule with slow growth. Pain and adjacent lymphadenopathy are leading symptoms of the patient. Histological examination shows the classical morphological features of AFH with focal cellular atypia. The tumor has immunoreactivity to vimentin and CD68 but negative to CD34, desmin, CD117 and S-100 protein. Because of its rarity, we report a case with an uncommon clinical presentation in a Thai patient.