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Pleomorphic fibroma of the skin: a benign neoplasm with cytologic atypia. A clinicopathologic study of eight cases.Am J Surg Pathol. 1989 Feb;13(2):107-13.
A clinicopathologic study of eight examples of polypoid and dome-shaped cutaneous fibrous lesions with sparse cellularity but striking nuclear atypia and rare mitotic figures is presented. Positive immunohistochemical staining for vimentin and actin supported the fibroblastic nature of these lesions. All eight cases were adults whose ages ranged from 33 to 67 years (mean 52 years). Five were women and three were men. Five lesions were located on extremities, two on the trunk, and one on the face and they measured from 4 to 16 mm in greatest dimension. The lesions were clinically followed from 4 months to 5 years. They all showed benign clinical behavior, with only one local recurrence in a lesion that had been incompletely removed. The nuclear atypia seen in these fibrous lesions may be similar to that which occurs in other benign mesenchymal neoplasms, such as pleomorphic lipoma, pleomorphic leiomyoma, ancient schwannoma, and variants of dermatofibroma with atypical cells. We suggest that "pleomorphic fibroma" is an appropriate term for this lesion based on its histologic differentiation, cytologic atypia, and benign clinical course.
Pleomorphic fibroma of the skin, a form of sclerotic fibroma: an immunohistochemical study.Clin Exp Dermatol. 1998 Jan;23(1):22-4.
We report a new case of pleomorphic fibroma of the skin arising on the face. The lesion was polypoid and fibrous, located on the dermis, and formed by coarse collagen bundles with sparse cells. It was also characterized by the presence of cellular atypia and pleomorphism without mitosis. Immunohistochemistry showed staining for vimentin and actin and negativity for S-100, CD34, CD68, alpha-1-antichymotrypsin and alpha-1-antitrypsin antigens, supporting a myofibroblastic origin. A few isolated cells also showed granular cytoplasmic detection of factor XIIIa. Although the disorder has been previously considered to be a tumour of preferential localization on the trunk or extremities, this does not always hold true as four of the 14 reported cases arose on the head. Pleomorphic fibroma is a benign condition and is we believe a variant of sclerotic fibroma.