Solitary sclerotic fibroma of the skin: a sclerotic dermatofibroma?

Cowden Disease: A Review

ABSTRACT

PTEN hamartoma tumor syndrome (PTHS) includes diseases with germline pathogenic variants in the PTEN gene. Cowden syndrome is included in this syndrome . PTEN (phosphatase and tensin homolog) is a tumor suppressor gene located on chromosome 10q22-23; nearly 60%-90% of pathogenic variants are inherited. Cowden syndrome is a rare autosomic dominant condition, affecting approximately 1/200,000 people worldwide. Patients present benign and, malignant neoplasms in multiple organs, mostly breast and thyroid. The skin is the organ affected most consistently by Cowden disease. It is an autosomal dominant condition, characterized clinically by the presence of innumerable verrucous lesions on the skin. Interpretations of histopathologic findings in the cutaneous and mucosal lesions continue to be a matter of debate.

Epithelioid fibrous histiocytoma: three diagnostically challenging cases with novel ALK gene fusions, unusual storiform growth pattern, and a prominent spindled morphology

Epithelioid fibrous histiocytoma (EFH) is a distinctive cutaneous neoplasm with a relatively variable morphological appearance. Recently, it has been shown that this tumor is molecularly characterized by ALK gene fusions. We report three EFHs with unusual histological presentation represented by a prominent/predominant spindle cell proliferation arranged in a variably storiform/whirling architectural pattern with or without stromal sclerosis. One of the cases closely resembled cellular fibrous histiocytoma. All three cases were immunohistochemically ALK-positive and were analyzed for ALK gene rearrangements using a next-generation sequencing-based assay (FusionPlex Sarcoma Kit, ArcherDx). Three novel fusions, namely AP3D1::ALK, COL1A::ALK, and LRRFIP2::ALK, were detected and further confirmed by FISH in all 3 cases and RT-PCR in 1 case. All patients were elderly (62-63 years) and presented with a solitary polypoid lesion on the extremities. The awareness of these morphological variants is important since it entertains a wide and slightly different differential diagnosis than conventional EFH. We also presented evidence that a clear separation of EFH from BFH in all cases may not be as straightforward as previously thought. The consistent ALK immunoexpression and the continually expanding scale of ALK gene rearrangements provide a useful tool to distinguish EFH from its histologic mimics.

Two Cases of Sclerotic Fibroma of the Skin that Mimicked Keloids Clinically

Sclerotic fibromas of the skin (SFSs) have a very characteristic histology but the clinical signs are non-specific. Consequently, it is extremely difficult to make a diagnosis of SFS on the basis of the clinical findings only. We report here two cases of SFS arising on the right scapular region and the right lower leg, respectively. Both cases were clinically similar to keloids. Skin surgeons should remember that SFSs are an important differential diagnosis from keloids.

Late-Stage Erythema Elevatum Diutinum Mimicking a Fibroblastic Tumor: A Potential Pitfall

Erythema elevatum diutinum (EED) is a rare dermatosis with evolving histopathological features that vary according to the age of the lesions, with a variable fibrosis and a fascicled proliferation of spindle cells in late phases. The authors present an otherwise healthy 57-year-old woman with multiple indurated nodules on the inner aspect of both feet. Skin biopsy showed storiform interlacing bundles of spindled cells with plump nuclei and some areas with neutrophils and leukocytoclasia. CD34 and S100 were negative. This case is noteworthy clinically due to its location and its histopathological presentation that comprises a wide differential diagnosis, including inflammatory pseudotumor, dermatofibrosarcoma protuberans, superficial nodular fasciitis, hyalinized leiomyoma, sclerosing spindle cell perineuroma, and sclerotic fibroma. The authors have reviewed the main histopathological and immunohistochemical features that help in the differential diagnosis of this rare variant of EED. A careful search for leukocytoclasia and neutrophilic vasculitis is mandatory to establish the right diagnosis of nodular or late-stage EED and avoid the pitfall of considering this a neoplastic process.

Vaccine-associated fibrosarcoma with keloidal differentiation in a cat

A 6-year-old Domestic Shorthair cat was presented with a history of subcutaneous mass of the lateral left hind limb. The subcutaneous mass developed over a period of approximately 16 months subsequent to administration of Feline leukemia virus vaccines. Based on the histopathological and immunohistochemical examination, the subcutaneous mass was diagnosed as vaccine-associated fibrosarcoma with keloidal differentiation.

FGF-R3 and OPG expression in patient with multiple myeloma following systemic sclerosis: case report and review of the literature

The presence of multiple myeloma (MM) in a patient with systemic sclerosis is a rare and unusual occurrence with unclear significance. We report the case of a 55-year-old woman with a 20-year history of systemic sclerosis, who subsequently presented with clinical stage IIIA IgG-λ MM. The systemic sclerosis was diagnosed and treated in 1988 with D: -penicillamine and methotrexate. Twenty years later, in December 2008, she presented with symptoms of Raynaud's phenomenon and intense facial pruritus. Immunoelectrophoresis confirmed the presence of a IgG-λ paraprotein (71.90 g/l) and Bence Jones proteinuria of the lambda light chains. Bone marrow histology revealed infiltrates of plasmocytes and lymphoplasmocytes which were on immunohistochemistry CD38+, FGF-R3+ and OPG+. An extensive X-ray skeletal survey did not show any osteolytic lesions or fractures. The patient was treated according to the CTD protocol (cyclophosphamide, thalidomide, and dexamethasone) which was effective against the myeloma as well as the systemic sclerosis and patient achieved complete remission.

Sclerotic epithelioid dermatofibroma

Dermatofibroma ("fibrous histiocytoma") is a common soft tissue lesion with many variants based on a great variety of architectural patterns, cellular morphology and stromal reactions. The coexistence of 2 or more patterns within a single lesion is well known and causes diagnostic difficulties. We report a case of an unusual histologic presentation of a solitary sclerotic and epithelioid dermatofibroma in a 48-year-old woman.

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

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.

Ultrastructural and immunohistochemical characterization of the so-called giant multinucleate cells in cutaneous collagenomas

AIMS

This study was undertaken to compare the histopathological, immunohistochemical and ultrastructural features of the so-called giant multi nucleate cells in cutaneous collagenomas: giant-cell collagenoma and solitary sclerotic fibroma.

METHODS AND RESULTS

We studied four collagenomas: one giant-cell collagenoma and three solitary sclerotic fibromas. All the cases showed an indolent clinical presentation and were histologically constituted by a well-demarcated dome-shaped proliferation of coarse collagen bundles with a varying number of interspersed giant multinucleate cells and stellate mononuclear cells. The immunohistochemical study on paraffin sections revealed that neoplastic cells in both collagenomas were vimentin and CD34-positive, whereas FXIIIa was only expressed in solitary sclerotic fibromas. In regard to the so-called giant multinucleate cells, we have ultrastructurally found that these cells were 'real' multinucleate cells in giant-cell collagenoma, whereas in solitary sclerotic fibromas they consisted of closely packed aggregates of individual stellate mononuclear cells. Moreover, perinuclear cisternae focally containing finely textured material of moderate density were unexpectedly found in giant cells of giant-cell collagenoma, a finding which was not observed in solitary sclerotic fibromas. Additionally, a characteristic cell-cell interaction between tumour cells and mast cells was encountered in all collagenomas.

CONCLUSIONS

This study supports a distinctive immunohistochemical and overall ultrastructural profile of giant multinucleate cells in giant-cell collagenoma and solitary sclerotic fibroma, which suggests a different pattern of differentiation for these two related cutaneous lesions.

Pleomorphic sclerotic fibroma: a case report and literature review

Pleomorphic sclerotic fibroma is a benign neoplasm exhibiting features of sclerotic fibroma and pleomorphic fibroma. We report another such case. The tumor presented as a firm, 0.5-cm, flesh-colored papule on the forehead of a 72-year-old white man for an unknown duration. Histologic examination revealed a neoplasm in which the superficial portion showed features of a pleomorphic fibroma, the deeper portion showed features of a sclerotic fibroma, and a transitional area was present in between. We propose that pleomorphic fibroma, sclerotic fibroma, and pleomorphic sclerotic fibroma form a spectrum. Pleomorphic sclerotic fibroma may be used as a broad diagnostic term to encompass the spectrum.

Dermatofibroma with sclerotic areas resembling a sclerotic fibroma of the skin

BACKGROUND

Dermatofibromas are common benign tumors that occur as single or multiple nodules on the extremities in adults. Sclerotic fibroma of the skin (SFS) is a benign tumor characterized histopathologically by a well-demarcated, non-encapsulated dermal nodule composed of hypocellular, sclerotic collagen bundles with prominent clefts. The pathogenesis of these two conditions is still in dispute.

METHODS

We present a case of dermatofibroma with sclerotic areas resembling a sclerotic fibroma of the skin and a review of the literature.

RESULTS

The tumor showed a well-demarcated dermal, fibrocollagenous tumor with three different histopathological features. One-fourth of the lesion was consistent with dermatofibroma. Another area adjacent to dermatofibroma revealed hyalinized eosinophilic collagen bundles arranged in the characteristic interwoven pattern with prominent clefts, as is described in sclerotic fibroma of the skin. One-half of the lesion between the dermatofibroma and sclerotic fibroma showed transitional changes from dermatofibroma to sclerotic fibroma.

CONCLUSION

According to these findings, the possibility that sclerotic fibroma is an ancient or degenerated stage of dermatofibroma cannot be completely ruled out, but some authors still consider that dermatofibroma and sclerotic fibroma of the skin are completely different neoplasms.

Keloidal fibromas and fibrosarcomas in the dog

Sixteen dogs (2-12 years of age) presented with one (n = 15) or two (n = 1) cutaneous nodules (n = 16) or a dermal plaque (n = 1). Intact males (n = 9) and neutered males (n = 4) were more affected than were females (n = 3). Histologically, these lesions were characterized by focal dermal and subcutaneous deposition of thick hyalinized collagen fibers intermingled with fibroblasts, and in 13 of 17 lesions, a variable number of CD18-positive cells were interpreted as reactive macrophages. Fibroblasts in three dogs formed intersecting fascicles, interpreted as evidence of malignant transformation. The terms keloidal fibroma and keloidal fibrosarcoma can be applied to these lesions. Excision was curative in five dogs with keloidal fibroma for which follow-up was available. However, because malignant transformation may occur, wide excision of canine keloidal lesions is warranted.

Pleomorphic sclerotic fibroma

We report the clinical and histologic features of 2 cutaneous tumors demonstrating many of the usual features of sclerotic fibroma, an entity that is well described in the literature. Our cases differed from the usual form of sclerotic fibroma in that they demonstrated marked focal cellular pleomorphism without increased mitotic activity. We suggest the term pleomorphic sclerotic fibroma for these lesions.

Expression of CD34 in sclerotic ("plywood") fibromas

CD34 antigen is expressed in normal human skin on endothelium, in spindle cells located around adnexal structures, and in a subset of interstitial cells in the reticular dermis. CD34 expression has also been identified in a number of fibrohistiocytic neoplasms, such as dermatofibrosarcoma protuberans and solitary fibrous tumors of soft tissue. CD34 expression has not previously been described in sclerotic, or "plywood" fibromas. Here presented are three lesions from three patients, in which histologic examination revealed a well-circumscribed dermal nodule composed of spindled cells with focal nuclear pseudo-inclusions. There was extensive fibrosis with hypocellular, storiform areas, characteristic of sclerotic fibroma. The spindled cells strongly expressed CD34, but not factor XIIIa or markers of melanocytic, neural, or muscular differentiation. A diagnosis of Cowden syndrome was considered in one of the cases. These cases provide evidence that CD34 expression can occur in sclerotic fibromas, either solitary or associated with Cowden syndrome. When diagnosing a sclerotic fibroma, one should comment in the report regarding the possibility of Cowden syndrome.

Solitary sclerotic fibroma of the skin: degenerated sclerotic change of inflammatory conditions, especially folliculitis

Two cases showing changes of sclerotic fibroma developed in association with an inflammatory process, especially folliculitis. The lesion in the first case showed a well-circumscribed, nonencapsulated nodule in the dermis, which consisted of a perifollicular fibrotic area and a peripheral sclerotic area. In addition to the usual findings of sclerotic fibroma, spindle cells were heavily infiltrated in a storiform and fascicular pattern around the degenerated hair follicle, suggestive of dermatofibroma. The lesion in the second case showed the typical findings of sclerotic fibroma in association with folliculitis and hair follicle remnants. Our observations suggest that solitary sclerotic fibroma of the skin may be a degenerated or sclerotic end stage of other fibrous conditions, such as dermatofibroma, and that it may be induced by inflammation, especially folliculitis.

Recurrent sclerotic fibroma of the skin

The pathologic findings of a sclerotic fibroma of the skin may resemble those of other benign cutaneous lesions. In this report, the sequential pathologic changes of a recurrent sclerotic fibroma of the skin during a period of 7 years are documented. As the lesion became older, there was not only a decrease in cellularity, but also a progressive organization of the collagen bundles toward a "plywood-like" appearance.

Pacinian collagenoma

An unusual histological variant of collagenoma is described. A 36-year-old woman presented with a lump in the left hypothenar eminence. Histological examination revealed a well-delineated lesion composed of paucicellular collagen fibres arranged in concentric lamellations giving rise to an onion skin appearance. The overlying epidermis was thin and the lateral borders were demarcated by an epidermal collarette. Inflammation and xanthoma cells were absent and occasional capillaries were present. The lesion was positive for collagen stains, reticulin and CD34. This lesion represents an uncommon histological form of collagenoma or fibroma. It can be distinguished from histological look-alikes on the basis of the characteristic morphology and immunophenotype.

Giant cell collagenoma: a benign dermal tumor with distinctive multinucleate cells

We present five cases of a hitherto unreported cutaneous neoplasm. The tumors appeared as solitary slow-growing flesh-colored nodules arising in young and middle-aged adults. They were located on the trunk, the upper extremities, and the face, and did not recur after complete excision. Clinically, they were diagnosed as dermal nevus, Spitz's nevus, fibroma, or neurofibroma. Histology revealed polypoid flat-dome-shaped lesions with a sharply demarcated matrix consisting of coarse hyalinized collagen bundles arranged in a prominent storiform pattern and separated by mucin-containing clefts. Despite a low overall cellularity, the tumors contained numerous, occasionally bizarre-shaped, multinucleate giant cells with crowded vesicular nuclei and a pale staining foamy cytoplasm, as well as plump fibroblastlike cells with analogous nuclear morphology. Atypical nuclei or mitotic figures were not observed. The cells were strongly positive for vimentin but negative for cytokeratin, smooth muscle actin, desmin, S-100 protein, CD34, factor XIIIa, and the macrophage markers KP1, Mac 387, and Ki-M1p, suggesting a fibroblastic origin. Based on the overall architecture, we conclude that these tumors probably represent a distinctive variant of solitary circumscribed storiform collagenoma (sclerotic fibroma) and propose the designation of giant cell collagenoma.