Nodular fasciitis (pseudotumor of the skin)

A 34-year-old man complained of a nodule on the flexor aspect of his forear m which had been present for a year. Histopathology showed a circumscribed lesion of fascicles of spindle cells within a mucoid intervening matrix. Th e cells were positive for vimentin, a-actin and LU 5. The proliferation mar kers PCNA and Ki-67 indicated a high mitotic activity and growth rate. A di agnosis of subcutaneous nodular fasciitis (NF) was made. NF belongs to the group of inflammatory myofibroblastic tumors. The pseudotumoral clinical an d histological aspect of NF may lead to misdiagnosis.