Sclerotic fibroma‐like change in various neoplastic and inflammatory skin lesions: is sclerotic fibroma a distinct entity?

Abstract

Sclerotic fibroma was first described in association with Cowden's disease by Weary et al. in 1972. In 1989, Rapini and Golitz detailed 11 cases of solitary sclerotic fibroma (SFS) in the absence of Cowden's disease, suggesting the term SFS of the skin. Classic histological features include hypocellular, hyalinized bands of collagen sharply demarcated from the surrounding skin. Numerous authors have described sclerotic fibroma-like changes in other entities including melanocytic nevi, dermatofibromas, lipomas, tendon sheath fibromas, giant cell collagenomas, neurofibromas, angiofibromas, erythema elevatum diutinum, and folliculitis. Dissension has arisen, with some dermatopathologists asserting that sclerotic fibroma is just an evolutionary end-point of a previous lesion. Others contend that SFS is a distinct lesion and cite recurrent cases and/or proliferation marker studies to corroborate this view. We detail the histopathological findings of lesions consistent with the classic description of SFS and compare these to sclerotic changes observed in an intradermal nevus, blue nevus, erythema elevatum diutinum, neurofollicular hamartoma, angiofibroma, neurofibroma, accessory nipple, and dermatofibromas. Sclerotic fibroma-like change may be seen in a variety of lesions and may represent a common reaction pattern in the skin.

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.…”

“…A solitary variant of SF in the absence of the other manifestations of Cowden syndrome was later reported in 1989 by Rapini and Golitz 3 . Two theories have classically been used to explain the pathogenesis of SF: the first considered it to be a distinct lesion (may especially explain those cases associated with Cowden syndrome), whereas the second described it as a sclerotic evolutionary end‐point of many conditions (such as folliculitis, dermatofibromas, neurofibromas, angiofibromas or erythema elevatum diutinum) 1,3–5 . In support of the second theory, we report a rare case of a solitary sclerotic fibroma on the scalp of a young girl associated with findings of chronic folliculitis and discuss the differential diagnosis.…”

“…There is usually absence of adnexal structures. The epidermis overlying the lesion is usually atrophic 3,5 . On immunohistochemistry, the spindle cell infiltrate most consistently shows positive staining with vimentin, while staining with CD34 has been inconsistent with some cases showing negative staining while others show focal positivity 5,6 …”

“…The etiopathogenesis of sclerotic fibroma rests on two main theories, which may both be correct depending on the presentation. The first theory regards SF as a unique distinctive proliferative fibrous tumor mainly based on its association with Cowden syndrome and its ability to recur 1,5,7 . The second theory considers it to be an involutional sclerotic stage of a pre‐existing lesion.…”

Mucocutaneous Neuromas

“…The presence of multiple neuromas (especially involving acral sites) may prove to be more specific for PHTS than other cutaneous findings that serve as diagnostic criteria (eg, lipomas, fibromas, and acral keratoses). 2,34,91 Because the exact risk of malignancy associated with forms of PHTS other than CS has not yet been determined, it is recommended that patients with PHTS be monitored following the CS guidelines. .…”