Myxoid plexiform fibrohistiocytic tumour.

Plexiform fibrohistiocytic tumour is a low-grade malignant mesenchymal neoplasm of myofibroblastic origin with the capacity for biphasic differentiation toward a fibroblastic or histiocyte-like morphology. We report a case of this rare tumour presenting as a tender subcutaneous nodule on the scalp of a 58-year-old man. Histopathological examination revealed multinodular biphasic proliferation of fibroblast-like and histiocyte-like cells with a few osteoclast-like giant cells. This case is notable for the rare myxoid changes, which may reflect a different behaviour of this tumour when occurring in older people.