Pleomorphic fibroma of the skin, a form of sclerotic fibroma: an immunohistochemical study

Abstract

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.

Solitary sclerotic fibroma on the scalp of a young girl: reactive sclerosis pattern?

“…These findings raised the question of a possible preceding chronic folliculitis or a keratin cyst that ruptured. Finally, the prominent cellular component observed in our patient, which has been previously reported in a few case reports, was alarming especially that it occurred in a pediatric patient 3–8 . This histological feature raised a differential diagnosis that mainly includes other spindle cell tumors such as fibrous tumors (dermatofibrosarcoma protuberans, pleomorphic fibroma and keloid), as well as tumors of neural, melanocytic and muscle origin.…”

Cytomorphology of pleomorphic fibroma of skin: A diagnostic enigma

“…[13] Degeneration, ischemia, or the paracrine influence of mast cells may create the cytological atypia in PF. [145] Two variants have been described: Myxoid and sclerotic. [67] In fact, some investigators have postulated that the PF of the skin is actually a variant of the sclerotic fibroma.…”

“…[67] In fact, some investigators have postulated that the PF of the skin is actually a variant of the sclerotic fibroma. [48] Other researchers have called these as pleomorphic sclerotic fibromas. [9]…”

“…Positive expression of muscle-specific actin, CD34 and rarely alpha-1 antichymotrypsin, has also been observed. [1348–10]…”

Loss of retinoblastoma in pleomorphic fibroma: An immunohistochemical and genomic analysis

“…Despite the atypical cytologic features, the proliferative index was low with rarely identified cells in mitosis and clinical follow up was benign. Additional reports demonstrate that pleomorphic fibroma may exhibit marked variability in stromal alteration, ranging from sclerotic to fibrotic to myxoid, and may pose a diagnostic challenge in some cases . In cases with exuberant sclerosis, some authors have identified immunohistochemical overlap with sclerotic fibroma (sclerotic pleomorphic fibroma) …”