Solitary sclerotic fibroma

A 63-year-old Chinese man with a solitary sclerotic fibroma on the abdomen is described. Skin biopsy showed a well-demarcated dermal nodule composed of hypocellular, eosinophilic collagen bundles separated by prominent clefts. Retrospective electron microscopic study revealed wide collagen bundles containing tightly packed collagen fibrils, only 50 nm in diameter. There were no signs of Cowden's disease. To our knowledge, this is the first report of electron microscopic study of sclerotic fibroma. A brief review of the literature is included.     

Pure sclerotic neurofibroma: a neurofibroma mimicking sclerotic fibroma

BACKGROUND: Neurofibroma (NF) is a benign tumor of the nerve sheath. Several variants of NF have been described. PURPOSE: We report a case of NF with sclerotic changes resembling sclerotic fibroma (SF). METHODS AND RESULTS: The patient was a 61-year-old man who had an asymptomatic cutaneous lesion on the right scapular region. Physical examination revealed a pedunculated, white-to-pinkish nodule that had a firm consistency, spherical morphology, and smooth surface. Microscopically, the nodule showed a well-circumscribed, nonencapsulated dermal tumor composed of scant cells and thick collagen bundles with prominent clefts. The tumor cells were immunoreactive for vimentin and S100 protein. The patient was diagnosed as having pure sclerotic NF. To our knowledge, only five cases of NF with SF-like pattern have been previously published, and in two this pattern was pure. CONCLUSION: It is important to recognize this exceptional type of NF because it may be easily confused with SF, as well as with a wide variety of neoplasms or hamartomatous conditions containing similar sclerotic pattern.     

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.     

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.     

Solitary sclerotic fibroma of skin: a possible link with pleomorphic fibroma with immunophenotypic expression for O13 (CD99) and CD34

BACKGROUND: Solitary sclerotic fibroma (SF) presents as a well circumscribed dermal nodule, composed of sparse spindle cells with alternating wavy collagen fibers arranged in a storiform pattern. The histogenesis and nature of this histologically distinct lesion are uncertain. Whether this peculiar tumor represents a true hamartoma or a degenerating end of various fibrous lesions such as pleomorphic fibroma (PF), dermatofibroma, or angiofibroma is still controversial. High proliferating index of spindle cells in SF argues against the possibility of being a degenerating end product of another lesion. METHODS: We studied morphological features and immunoprofile of eight SFs, in comparison with four PFs, one collagenized dermatofibroma, two angiofibromas, and two periungual fibromas. Immunostains for CD34, CD31, O13 (CD99), Factor XIIIa, S-100, CD68 (KP-1), and MIB-1 were carried out using a labeled streptavidin-biotin method with DAKO-automated immunostainer. Paraffin blocks of two SFs were reprocessed for electron microscopic studies. Clinical data of all patients with SF were also reviewed. RESULTS: Spindle cells and pleomorphic cells in SF and PF showed diffuse immunoreactivity for CD34 and O13 but were negative for CD31, S-100, and CD68. Spindle cells in one dermatofibroma and one angiofibroma were positive for Factor XIIIa. Proliferating index (MIB-1) was very low in all cases of SF, contradicting some previous reports. CONCLUSIONS: SF is a fibrotic lesion with cells positive for CD34 and O13. It shares a common immunoprofile with PF but is distinct from dermatofibroma and other common spindle cell lesions of skin. O13 expression in SF has not been previously described.     

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

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, α-1-antichymotrypsin and α-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.     

Pacinian collagenoma: A distinct form of sclerotic fibroma

Sclerotic fibroma (storiform collagenoma) is a rare benign skin tumor. A solitary tumor, as well as multifocal lesions, are found either sporadically, or associated with Cowden syndrome. The tumor usually presents as clinically asymptomatic, slowly growing papule or nodule on the skin of the head, neck, and upper extremities. Microscopically the lesion is sharply demarcated, composed of hyalinized bands of collagen with low cellularity and a distinctive irregularly whorled or storiform pattern. We describe a case of a unique variant of this tumor in the scalp of a 33-year-old male. The tumor was microscopically composed of concentrically arranged collagen bundles with prevailing type III collagen, which resembled an enlarged Vater-Pacini corpuscle, with low density of CD34-positive and glucose transporter 1-negative spindle shaped cells. The specific microscopic appearance is suggestive of the term “Pacinian collagenoma” for this unique benign tumor.     

Solitary sclerotic fibroma of the skin: morphological characterization of the 'plywood-like pattern'

Sclerotic fibroma is an uncommon skin tumor. Rapini and Golitz reported 11 cases of solitary sclerotic fibromas in patients without Cowden's disease in 1989. We report a case of sclerotic fibroma that presented as an asymptomatic nodule in a 34-year-old Japanese man. Histopathological examination revealed typical features of sclerotic fibroma of the skin. Ultrastructural examination showed that spindle cells with myoid features had proliferated around the vasculature. They had segregated from the perivascular area by leaving the surrounding basal lamina, resulting in their phenotypical change to produce collagen accumulating in a concentrically lamellar fashion. We suggest a possible role of abnormal blood vessels and surrounding specific cells in the development of sclerotic fibroma.     

Sclerotic fibromas of the skin.

We report a case of a 34-year-old Japanese woman with a fibrous tumor on the left palm that fulfilled the criteria of sclerotic fibroma of the skin. Immunohistochemically, the tumor cells were positive for vimentin, but negative for S-100 protein and neuron-specific enolase. Ultrastructurally, the cross-striations of collagen microfibrils were less prominent. Our case supports the concept that sclerotic fibroma of the skin is a distinctive lesion which may represent a hamartoma of the skin.     

Sporadic sclerotic fibroma of the oral soft tissues

Sclerotic fibroma (SF) is an uncommon, benign fibrous neoplasm that may present either as a sporadic, small, solitary cutaneous mass, in otherwise healthy individuals, or as solitary or multiple, discrete skin nodules in patients with Cowden syndrome. Oral SF has been reported in patients with Cowden syndrome; however we now report the first documented series of sporadic SF originating within the oral mucosa. We describe 5 cases of SF arising in 3 women and 2 men with an age range of 43 to 66 years. The buccal mucosa was the site of involvement in 4 patients and the lower lip in 1 patient. Microscopically, each of the tumors was characterized by an unencapsulated, well-circumscribed, hypocellular submucosal nodule that was sharply demarcated from the surrounding tissues. The neoplasms were primarily composed of thick collagen bundles that were occasionally arranged in a storiform pattern. Prominent clefts separated many of the collagen bundles. In all cases, spindle and stellate-shaped cells containing fusiform or stellate-shaped nuclei and inconspicuous nucleoli were found scattered throughout the lesion. Occasional stellate-shaped, multinucleated cells were also seen. Many of the cells also exhibited long dendritic cytoplasmic processes. The tumor cells strongly expressed CD34 and vimentin, and occasionally factor XIIIa, but were negative for markers of myofibroblastic, neural or melanocytic differentiation. These findings confirm that oral SF represents a unique entity and should be differentiated from more commonly occurring benign fibrous lesions of the oral soft tissues.     

Solitary sclerotic neurofibroma of the skin

Solitary neurofibroma of the skin is a benign soft tissue tumor. Clinically, it is a flesh-colored, slow-growing, soft tumor and sometimes shows diverse histological patterns. We present here a case of nontender, hard neurofibroma with sclerotic change. By transmission electron microscopic observation, some mast cells in close contact with fibroblasts and abundant collagen fibers were seen in the lesion. Our findings suggest that mast cells may have played a role in the formation of the sclerotic regions of the current tumor.     

There is fat in this sclerosis: A case report of sclerotic lipoma and review of the literature

Sclerotic lipomas, a lipoma variant, are benign subcutaneous tumors, so-named because of their resemblance to sclerotic fibromas. Previous literature has suggested that these tumors may show a predilection for middle-aged adult males. We report an unusual case of a sclerotic lipoma diagnosed on the scalp of a 66-year-old female. The patient presented to the outpatient clinic with a 3- to 4-year history of an enlarging and irritated 2.6-cm nodule on the anterior crown of the scalp, clinically thought to be a pilar cyst. Histopathological examination from the excisional specimen revealed a well-circumscribed dermal to subcutaneous tumor with ample sclerotic collagen bundles, an increased number of CD34 positive spindled cells, and prominent S-100 positive mature adipocytes comprising greater than 50% of the tumor. We present this case given its atypical clinical and histopathological presentation, review the literature of sclerotic lipomas, and discuss the differential diagnosis to raise awareness of this rare entity.     

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.     

皮肤纤维瘤105例分析

皮肤纤维瘤是来源于皮肤成纤维细胞的一种良性肿瘤。还是类似于癜痕组织的一种炎症后反应,就上述问题查阅105例皮肤纤维瘤病例,重新阅片并结合病史加以总结。组织病理显示所有的切片均表现为纤维组织不同程度的增生,其外周血管充血及炎细胞浸润。结合病史认为皮肤纤维瘤是类似于瘢痕组织的一种炎症后反应。     

Animal model of sclerotic skin. I: Local injections of bleomycin induce sclerotic skin mimicking scleroderma

We have established a mouse model for scleroderma induced by repeated local injections of bleomycin (BLM). Daily injection of BLM at a dose of >10 microg per ml for 4 wk induced histologic changes of dermal sclerosis, but not fibrosis, with thickened and homogenous collagen bundles and cellular infiltrates in BALB/C mice, whereas clinical signs of scleroderma were not apparent. In addition, lung fibrosis was also induced preceding the cutaneous changes. Sclerotic changes were not found in other sites of the skin distant from the injection site. Dermal sclerosis could also be induced by injecting BLM only every other day. The sclerotic changes of the dermis were sustained after ceasing BLM applications for at least 6 wk. Mast cells gradually increased in number as the sclerotic changes developed. Marked degranulation of mast cells was observed with elevated histamine release. The amount of hydroxyproline in skin was significantly increased at 4 wk of BLM treatment as compared with that in untreated or phosphate-buffered saline-treated mice. Anti-nuclear antibody was detected in serum of BLM-treated mice. Transforming growth factor-beta1 mRNA was detected at an early phase, while transforming growth factor-beta2 mRNA was strongly expressed at 4 wk when the sclerotic features were prominent. These results suggest that dermal sclerosis induced by BLM closely resembles systemic sclerosis both histologically and biochemically. Our mouse model can provide a powerful tool of inducing dermal sclerosis to examine the pathogenesis and the therapeutic approach of scleroderma.     

Giant cell collagenoma: case report and review of the literature

BACKGROUND: Giant cell collagenoma (GCC) is a recently described cutaneous fibrous neoplasm that usually affects young to middle-aged adults. Despite its similar histological appearance with circumscribed storiform collagenoma, no association of GCC with Cowden's syndrome has been described so far. To the best of our knowledge only five cases of this rare fibrous tumor have been reported so far. METHODS: We report a case of a 79-year-old male patient presenting with a slow growing flesh-colored dome-shaped lesion in his left forearm, with a clinical diagnosis of fibroma. No stigma of Cowden's syndrome was depicted. RESULTS: The histological analysis showed a symmetrical and well-circumscribed flat-dome-shaped lesion covered by an atrophic overlying epidermis. The neoplasm was composed of hyalinized collagen bundles disposed in a whorled storiform pattern. Admixed with the collagen matrix, there were two distinct cell populations, one composed by spindle-shaped mononuclear cells, and the other composed by bizarre multinucleated giant cells. Immunohistochemical analysis showed positivity for vimentin and actin HHF35 in the mononucleated. The multinucleated cells only immunoexpressed vimentin. CONCLUSION: GCC is an unusual cutaneous fibrous tumor that should be differentiated from circumscribed storiform collagenoma, pleomorphic fibroma, regressive forms of dermatofibroma, and solitary myofibroma based on its histological features.     

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.     

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.     

Collapsing angiokeloidal dermatofibroma

ABSTRACT:: A heterogeneous group of benign fibrohistiocytic lesions has been assembled under the umbrella term, dermatofibroma. These lesions share a morphology of bland spindled cells encompassed by and intercalating through thick dermal collagen; unique variants have been described based on secondary histologic features, some of which include aneurysmal, myxoid, lipidized, signet ring, angiomatous, and keloidal. Here, we present a distinct dermatofibroma variant henceforth known as collapsing angiokeloidal dermatofibroma identified in 2 patients with slowly growing nodules of the buttock and the arm. Microscopically, the lesions have a characteristic dermatofibroma appearance but are accompanied by unusual diffuse small caliber vessels whose walls are collapsed by a thick, eosinophilic, keloid-like substance. The eosinophilic material resembles the adjacent dermal collagen; however, it does not stain for type-4 collagen or type-1 procollagen, amyloid, or glycogen. Although the exact composition of the keloidal material remains ambiguous, the architectural novelty of collapsing angiokeloidal dermatofibroma serves to further expand the morphologic spectrum of benign fibrous histiocytomas, although highlighting the difficulty in distinguishing between it and similar lesions.     

Composite Tumor Associating Trichoblastoma and Seborrheic Keratosis

Seborrheic keratosis is a common benign epidermal tumor histologically composed of basaloid and squamous cells. It mainly occurs on the face, scalp, and trunk, and presents clinically as a well-circumscribed, brownish to black papule, nodule, or plaque. Trichoblastoma is a relatively rare benign, slow-growing tumor showing differentiation toward the primitive hair follicle. It clinically manifests as a solitary, skin to erythematous colored, well-circumscribed dermal nodule located predominantly on the head and neck with a predilection for the scalp. Histologically, a well-demarcated mass of follicular germinative cells that show various degrees of differentiation, arranged in lobules, sheets, and nests, is located in the dermis or subcutaneous fat layer. We report the case of a 28-year-old female patient with a solitary, 2.0×4.0-cm black plaque with a 0.7-cm skin-colored nodule on the scalp. Histologically, the entire black plaque had prominent hyperkeratosis, acanthosis, and papillomatosis with horn cysts. The central nodule showed well-circumscribed, various-sized dermal tumor lobules without a connection to the overlying epidermis. The lobular aggregation was composed of numerous basaloid epithelial nests and multiple primitive papillary structures with distinct peripheral palisading of nuclei. According to these findings, the scalp lesion was diagnosed as a composite tumor associating trichoblastoma and seborrheic keratosis.