Nodular Fasciitis : Microscopic

Comments:
The lesional cells of nodular fasciitis are uniform, plump, immature-appearing fibroblasts and myofibroblasts resembling those seen in tissue culture. They are arranged in short, intersecting fascicles with a storiform growth pattern. The cells have oval, uniform nuclei with prominent nucleoli. Mitotic activity is brisk (1-2 mitoses/5HPF), but there are no atypical forms.

Scattered lymphocytes, extravasated red blood cells (and microhemorrhages), foamy histiocytes, and multinucleated giant cells are also present.