title: Desmoplastic fibroblastoma (collagenous fibroma).
abstract: Desmoplastic fibroblastoma (DF) is a rare fibrotic tumor that has a wide anatomic distribution and it can appear in deep sections of the subcutis, in fascia, in aponeurosis or in skeletal muscles. This report describes a case of DF that appeared on the left side of the neck of a 55-year-old male as a 3.5-cm solitary, firm nodule. Histologically, it was composed of stellate or bland spindle-shaped cells embedded in a loose collagenous stroma. The entrapment of fat and muscle tissues was focally identified at the edges of the tumor. The stellate and multinucleated cells in the lesion were strongly positive for vimentin but negative for cytokeratin, smooth muscle actin, desmin, S-100, CD34, factor XIIIa, and CD68. These findings suggest that the stellate and multinucleated cells in the lesion were of fibroblastic origin and this neoplasm was pathologically benign.
authors.affiliation: Department of Dermatology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan. hirow@med.u-toyama.ac.jp
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Watanabe
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ishida
authors.forename: Kazuo
authors.initials: K
authors.lastname: Nagashima
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Makino
authors.forename: Osamu
authors.initials: O
authors.lastname: Norisugi
authors.forename: Tadamichi
authors.initials: T
authors.lastname: Shimizu
mesh_terms: D005350:Fibroma / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D006258:Head and Neck Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged