Pleomorphic fibroma of the skin with MDM2 immunoreactivity: A potential diagnostic pitfall

Pleomorphic fibroma is a rare benign cutaneous neoplasm characterized by spindle‐shaped cells and multinucleated giant cells scattered throughout collagenous stroma. These morphologic features can lead to diagnostic confusion, including atypical lipomatous tumor as one consideration. In contrast to atypical lipomatous tumor, previous studies have found pleomorphic fibroma to be negative for MDM2 immunohistochemical staining and MDM2 gene amplification. Here, we present a case of pleomorphic fibroma of skin with nuclear MDM2 immunoreactivity in the absence of MDM2 gene amplification, underscoring the superiority of fluorescence in situ hybridization as a diagnostic test in this differential diagnosis. The RB1 locus is also explored for differential diagnosis with pleomorphic/spindle cell lipoma and related entities.     

Pure apocrine nevus: immunohistochemical study of a new case and literature review

Apocrine nevi are benign adnexal cutaneous hamartomas characterized by localized hyperplasia of mature apocrine sweat glands (ASG). Although ASG proliferation can be found in a number of acquired or congenital adnexal skin tumors, pure apocrine nevi are exceedingly rare. We present herein a new typical case of this tumor that was studied immunohistochemically, and review the relevant literature in order to delineate its clinicopathological features.     

Subungual pleomorphic fibroma

BACKGROUND: Pleomorphic fibroma is a benign fibroblastic tumor characterized by pleomorphic, hyperchromatic cells or giant multinucleated cells embedded in a collagenous stroma. These cytologic features may lead to an incorrect diagnosis of malignancy. Most cases reported in the literature are located on trunk or extremities; the presentation as a subungual mass is rare. METHODS: We report an unusual case of a subungual pleomorphic fibroma in 66-year-old woman. Clinical information was obtained. Histologic examination and immunohistochemical studies were performed. RESULTS: A 66-year-old woman presented with a longstanding (40 years), subungual mass that deformed the nail of the left middle finger. Microscopic examination revealed a paucicellular tumor composed of hyperchromatic spindled, pleomorphic, floret-like giant cells embedded in haphazardly arranged collagen bundles in the dermis. No mitotic figures were seen. The tumor cells were vimentin-positive but did not stain with antibodies to S-100, cytokeratin, smooth muscle actin, factor XIIIa or CD34 negative. The diagnosis of a pleomorphic fibroma was made. Follow-up shows no evidence of tumor, 36 months after excision. CONCLUSION: Pleomorphic fibroma of the subungual region is an unusual cutaneous tumor with histologic features that may cause confusion with true sarcomas. This is only the second case reported of a subungual pleomorphic fibroma. Pleomorphic fibroma should be considered in the differential diagnosis of pleomorphic subungual tumors.     

Superficial fibrous tumors in childhood

A review is made of superficial fibrous tumors of childhood and differences between the pattern of fibrous tumor proliferation in children and adults are discussed. The fibrous tumors that occur specifically in childhood and infancy include recurring digital fibrous tumor, juvenile aponeurotic fibroma (cartilage analogue of fibromatosis), juvenile hyalin fibromatosis, fibrous hamartoma of infancy, congenital fibromatosis and fibromatosis colli (Torticollis). Palmoplantar fibromatosis and fibrosarcoma may appear in all ages. Dupuytren contracture, however, is not usually observed early in life. Similarly, the histiocytomas and dermatofibromas which are the most common fibrous tumors af adults are extremely rare in childhood.     

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.     

Plaque variant of trichoblastic fibroma

BACKGROUND: Tricoblastic fibroma is a rare benign skin tumor originating in the hair follicle. There are two clinical presentations: nodular and plaque variants. The plaque variant is almost exclusively located on the face with deep tissue infiltration. CASE REPORT: A 38-year-old man presented with a 2 cm diameter cutaneous plaque located on the right cheek. It had first been noted by the patient 3 years earlier and had enlarged slowly. On examination, the plaque was well defined, yellowish and slightly indurated. The first clinical diagnosis was basal cell carcinoma and the plaque was removed. Histology provided the diagnosis of trichoblastic fibroma. The patient remains well, with no evidence of recurrence, 10 months after excision. DISCUSSION: Trichoblastoma is an inclusive term for all benign cutaneous neoplasms that are mostly composed of follicular germinative cells. According to Altman, the plaque variant of trichoblastic fibroma is a poorly circumscribed neoplasm, particularly at its lateral and deep margins. This author also states that mitotic figures are more numerous in the plaque variant of trichoblastic fibroma and considers this clinical variant as a low-grade follicular malignancy.     

Primary Cutaneous Solitary Fibrous Tumor on the Back

Solitary fibrous tumors (SFT) are uncommon mesenchymal tumors. SFT have several synonyms including localized fibrous tumor, benign mesothelioma, localized fibrous mesothelioma, and submesothelial fibroma. SFT usually occur in the pleura or other serosal surfaces, but SFT can also develop in extrapleural areas including the nasal cavity, orbit, retroperitoneum, and pelvis. Cutaneous SFT is extremely rare, and more likely to occur in the head and neck region. Histologically, this tumor can mimic a variety of benign and malignant tumors such as dermatofibroma, dermatofibrosarcoma protuberans, spindle cell lipoma or other mesenchymal tumors. Most cases of SFT show non-aggressive clinical courses, with low recurrence rates. Herein, we describe a case of primary cutaneous SFT which presented with huge mass on the back.     

Multiple Nuchal-Type Fibromas on the Scalp: A Case Report

Nuchal-type fibroma is a rare, benign, fibrous, tumor-like proliferation characterized by dense hypocellular bundles of collagen, with sparsely scattered fibroblasts, interspersed fat tissue, and entrapped nerve fibers. It usually develops in the posterior neck as a solitary, firm, poorly circumscribed, subcutaneous mass. Herein, we report about a 32-year-old man who presented with a 6-year history of multiple nodules on the scalp. Histopathological features were consistent with those of nuchal-type fibroma. The tumors were surgically excised.     

Superficial acral fibromyxoma in the heel with new vascular features on dermoscopy

Superficial acral fibromyxoma (SAFM) is an uncommon mesenchymal soft tissue tumor with a predilection for the acral extremites and nail bed involvement. SAFM is diagnosed with clinicopathological and immunohistochemical examination. Awareness of this rare tumor is important because of amounts of benign and malignant neoplasms. We report a case of SAFM in a rare localization in the heel with a new finding on dermoscopy.     

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.     

Asymptomatic solitary mass on the sacral region

Nuchal‐type fibroma (NTF) is a rare, benign, tumour‐like fibrous proliferation of unknown pathogenesis. Despite the name, approximately one‐third of cases occur at extranuchal sites. We report a rare case of NTF of the sacral region, an extremely uncommon extranuchal site. As NTF is often misdiagnosed because of its rarity and histopathological similarity with other fibrous tumours, we present this case to increase understanding of this rare disease entity.     

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.     

Cemento-ossifying fibroma of the left mandible: A case report

Ossifying fibroma is a type of benign fibro-osseous lesion. Most lesions affect the mandible region, particularly the molar and pre-molar areas. It predominantly affects females between the second to fourth decades of life. Larger ossifying fibroma tumors require more extensive resection. CASE SUMMARYA 39-year-old female complained of occasional pain and tumor enlargement on her left jaw for the 3 years prior to presentation. Intraoral examination revealed a firm swelling on her left lower gum. Extraoral examination revealed swelling on the left mandible body with no erythema and superficial ulcer. Computed tomography scan revealed a circular-shaped lesion on the patient’s left mandible body with a well-defined radiolucent border, sized 3.2 cm × 2.8 cm × 0.9 cm. The tumor was removed by marginal mandibulectomy. Biopsy from the resected tumor suggested cemento-ossifying fibroma (COF). CONCLUSIONCOF is often unnoticed, but this slow-growing tumor can cause significant symptoms regarding its distortion into adjacent structures.     

Dermal desmoplastic fibroblastoma presenting as a large sacral mass

Desmoplastic fibroblastoma (collagenous fibroma) is a rare and recently recognised benign tumour. Most desmoplastic fibroblastomas arise in the subcutaneous tissue or skeletal muscle. Involvement of the dermis is extremely rare. We describe an unusual case of dermal desmoplastic fibroblastoma presenting as a large sacral mass in a 16‐year‐old male. An awareness of this entity is necessary to avoid confusion with other benign and malignant soft tissue neoplasms.     

Desmoplastisches Fibroblastom bei einer 22-jährigen Patientin im Bereich des Oberarms

Desmoplastic fibroblastoma (“collagenous fibroma”) is a rare benign, slowly progressive fibrous soft tissue tumor that ranges 1–20 cm in size. The tumor occurs in all ages, predominantly in the upper part of the body. Children are rarely affected. The tumor often infiltrates the subcutis; less often it invades the fascia and skeletal muscle or causes bone erosions. Histologically, the tumor is composed of spindle-shaped cells embedded in a densely collagenous stroma, sometimes forming a pseudo-capsule. Magnetic resonance imaging and computed tomography as well as ultrasonography are used to define the extensions of the tumor. Because it is clinically extremely difficult to determine if soft tissue tumors are benign or malignant, all should be excised with a margin of safety and examined histologically. We report a 22-year old woman with desmoplastic fibroblastoma located on the upper arm. Clinical and histopathological findings and treatment options are discussed.     

成人皮肤朗格汉斯细胞组织细胞增生症1例

目的探讨成人皮肤朗格汉斯细胞组织细胞增生症(LCH)的临床、组织病理学、免疫表型及电镜特征。方法报告1例罕见的成人皮肤朗格汉斯细胞组织细胞增生症,并结合文献分析其临床病理特征。结果该例先后经过4次病理活检,组织学特点为真皮全层弥漫分布的朗格汉斯细胞。瘤细胞表达CD1a、S-100、部分表达Langerin。电镜检查发现Birbeck颗粒。结论成人皮肤弥漫性LCH罕见,误诊率高。确诊应结合组织学特征、免疫表型及超微结构检查综合分析,疾病的预后与发病年龄、受累器官的多少有关。     

Extra-acral calcifying aponeurotic fibroma: a distinctive case with 23-year follow-up

Calcifying aponeurotic fibroma (CAP) is an unusual but well-characterized soft tissue neoplasm that typically involves the digits of children and frequently recurs locally. This report describes a case from the subcutis of the lumbosacral region. A 26-year-old man initially presented at age 3 and developed three recurrences over a 23-year period each at approximately 8-year intervals (ages 10, 18, and 26). The microscopic findings in all recurrences showed a lobulated, poorly circumscribed proliferation of dense fibrous tissue containing epithelioid-like fibro-blasts, multinucleated cells, and islands of metaplastic chon-droid differentiation with focal calcification. Despite origin from an unusual anatomic site, this case reported herein demonstrates the classical morphologic features and clinical history of CAT which showed little in the way of morphologic evolution despite 23 years of persistence. The clinical and histologic features helpful in distinguishing CAP from infantile fibromatosis and soft tissue chondroma are discussed.     

面部皮肤混合瘤的临床特征：18例报告并文献复习

 目的 探讨面部皮肤混合瘤的临床病理学特点、诊断与鉴别诊断。方法 对我院2017年3月至2021年9月间18例皮肤混合瘤患者资料进行回顾性分析。结果 18例患者中男9例,女9例;发病年龄为24~64岁。18例均发生于面部,鼻部最多见,均表现为单发无自觉症状的淡红色或肤色结节。初诊诊断为肿物待查12例,表皮囊肿2例,痣、皮脂腺瘤、钙化上皮瘤及瘢痕各1例。皮损组织病理均确诊为皮肤混合瘤,其中3例向小汗腺分化,15例向大汗腺分化。均行手术切除,随访2个月~1年,均无复发。结论 皮肤混合瘤是一种少见的皮肤良性肿瘤,确诊主要依赖组织病理学检查。