Atypical cutaneous fibrous histiocytoma

We report seven cases of atypical cutaneous fibrous histiocytoma, which appears to be a variant of cutaneous fibrous histiocytoma (dermatofibroma). These patients are all middle-aged women (mean, 39 years old) with small nodules occurring on the trunk and limbs. The lesions are characterized by marked focal cellular atypia, the absence of mitoses, and xanthomatous changes in both mononuclear and giant cells--all found within a small dermal nodule (approximately 1 cm) separated from an acanthotic epidermis by a Grenz zone. Their benign nature is demonstrated by the absence of recurrence, even after 9 years follow-up time.     

Polypoid dermatofibroma with a slim pedicle: a case report

Dermatofibroma, also called cutaneous fibrous histiocytoma or sclerosing hemangioma, is a fairly common, benign cutaneous tumor. Polypoid dermatofibroma is an unusual and poorly recognized form of this entity. We describe a peculiar case of this variant presenting with a unique morphology characterized by a round flat shape with a slim pedicle, although its histopathological picture was rather typical of that of ordinary dermatofibroma.     

Case for diagnosis

We report the case of an 11-year-old male patient with a histopathological and immunohistochemical diagnosis of dermatofibroma with an atypical clinical presentation on the right forearm. Although dermatofibroma is considered a benign skin tumor, some of its differential diagnoses, such as dermatofibrosarcoma protuberans and malignant fibrous histiocytoma, are truly aggressive. Lesions with atypical clinical aspects and topology associated with specific histopathological variants are some of the criteria for complete tumor excision.     

Multiple cutaneous fibrous histiocytomas in association with systemic lupus erythematosus

Cutaneous fibrous histiocytomas are usually regarded as superficial lesions and commonly known as dermatofibromas; however, unusual cases histologically showing fibrohistiocytic proliferation extending into the deeper dermis or subcutaneous tissues are occasionally experienced. Some authors propose this type as benign fibrous histiocytoma of the skin, distinct from dermatofibroma. We describe herein a case of systemic lupus erythematosus (SLE) who developed multiple nodules on the face, trunk and extremities. The nodule on the forehead did not present a typical clinical appearance of dermatofibroma, and histopathological examination showed fibrohistiocytic proliferation with a storiform pattern extending into the deep dermis and subcutaneous tissues. By contrast, histology of the nodule on the abdomen showed fibrohistiocytic proliferation confined to the dermis and compatible with dermatofibroma. Although multiple dermatofibromas are occasionally seen in patients with SLE, benign fibrous histiocytoma of the skin showing deeper invasion than dermatofibroma is rarely associated with SLE.     

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.     

Benign cellular fibrous histiocytoma with erosion of the phalanx

Fibrohistiocytic tumors are characterized by the presence of fibroblast like spindle cells and histiocytes. The benign fibrous histiocytoma (dermatofibroma, BFH) as well as the malignant dermatofibrosarcoma protuberans (DFSP) and the malignant fibrous histiocytoma (MFH) belong to this group. A recurrent painful, hard 2 cm tumor on the left hallux of a 54-year-old woman led to an erosion of the underlying phalanx. The patient had suffered from ingrown toenails for more than 10 years. Histologically there was a deep penetrating fibrohistiocytic tumor that grew in a storiform pattern with interspersed foam cells. The tumor was CD34 negative and mitoses were scarce. The diagnosis was benign cellular fibrous histiocytoma (BZFH). BZFH belong to the group of BFH with a high recurrence rate especially after incomplete removal. Damage to the underlying bone has not been reported so far.     

Variants of dermatofibroma - a histopathological study

Several variants of dermatofibroma have been described. They are essentially distinguished by their clinical and histopathological features. To review the mainfeaturesof these variants, a retrospective study of skin biopsies and tissue excisions of dermatofibromasperformed in the dermatology and venereology service at the Hospital Garcia de Orta between May 2007 and April 2012 was carried out. During that period, 192 dermatofibromas were diagnosed in 181 patients, the lesions being more common in women. Median age of the study population was 48 years. The most common lesion site was the limbs (74% of patients). The histopathological types found were common fibrous histiocytoma (80%) and the aneurysmal (5.7%),hemosiderotic (5.7%), epithelioid (2.6%), cellular (2.1%), lipidized (2.1%), atrophic (1.0) and clear cell (0.5%) variants. Based on these findings, this review focuses on the clinical and histological features of the various variants of dermatofibroma in terms of their clinical presentation, distinct histopathological features, differential diagnosis and prognosis.     

Atrophic dermatofibroma

Dermatofibroma is a benign fibrohistiocytic tumor, common and easily diagnosed when classical clinicopathologic features are present. The atrophic variant of dermatofibroma is of uncertain origin. This lesion is characterized clinically by a flat or atrophic and depressible surface. Histopathological features show reduction of the thickness of the dermis and elastic fibers. We report a typical case of this uncommon and probably underdiagnosed variant.     

Dermatofibroma with monster cells

Nineteen cases of dermatofibroma associated with monster cells are reported. The term "monster" (an animal with a strange or terrifying shape, one unusually large for its kind) implies a strikingly atypical cell with an extremely large nucleus. Except for monster cells, these 19 lesions had all of the typical histopathological findings of dermatofibroma. The clinical diagnosis for 16 of these lesions was dermatofibroma (or histiocytoma). Three lesions were submitted without any clinical diagnosis. Eighteen of 19 lesions occurred on the extremities. One was on the back. Monster cells are seen in the early, histiocytic stage of dermatofibroma when lipophages and/or siderophages are usually present in large numbers. Only rarely were mitotic figures seen in dermatofibromas with monster cells, and they were neither numerous nor atypical. It is important for histopathologists to distinguish dermatofibroma with monster cells from cutaneous malignant fibrous histiocytoma and radiation sarcoma. The criteria for differentiation concern primarily the architectural pattern of the lesion rather than its cytological features.     

Aneurysmal fibrous histiocytoma showing transition from factor XIIIa-positive to -negative

A 39-year-old woman visited us because of a subcutaneous induration on her forehead of 7 months' duration. The tumor was tender, firm, and colored blue-black. Microscopically, the tumor was composed of fibroblastic and histiocytic cells showing no atypicality. In some part intra- or extracellular haemosiderin was diffusely seen. There were some blood-filled spaces of varying size without endothelial lining. From these findings, this case was diagnosed as aneurysmal fibrous histiocytoma (AFH), a variant form of dermatofibroma. Immunohistochemical analysis showed that factor XIIIa-positive histiocytic cells were distributed in the area without haemosiderin, but such cells were absent in the area with its deposition. Furthermore, the cells near the blood-filled space showed transition from factor XIIIa-positive to -negative, suggesting that the stromal instability induced by the attenuation of factor XIII may lead the formation of the blood-filled spaces in AFH.     

Metastatic aneurysmal fibrous histiocytoma in a 20-year-old woman: A rare case report with review of the literature and discussion of its genomic features

Aneurysmal fibrous histiocytoma is an uncommon variant of cutaneous fibrous histiocytomas with a local recurrence rate of 19%. We present a case of aneurysmal fibrous histiocytoma in a 20-year-old female with a regional lymph node metastasis and subsequent satellite nodule. The patient initially presented with a 1-month history of two palpable nodules in left lower anterior shoulder and left axilla. Needle core biopsies from both lesions revealed an atypical spindle cell neoplasm with a differential diagnosis of aneurysmal fibrous histiocytoma and angiomatoid fibrous histiocytoma. The axillary dissection confirmed a metastatic deposit in 1 out of 22 lymph nodes. At 6 months a satellite nodule arose between the resection scar and the axilla histopathologically demonstrating a cellular spindle cell nodule at the dermis subcutaneous junction with large, blood-filled pseudovascular spaces lined by histiocytes. The periphery of the lesion showed collagen trapping without a lymphoplasmacytic infiltrate. The lesional cells were diffusely positive for CD10 and focally for CD68 and Illumina RNA fusion panel sequencing was negative. Herein we present this case of metastatic aneurysmal fibrous histiocytoma with review of the literature and discussion of biology, cytogenetic alterations, and differential diagnosis.     

Epithelioid cell histiocytoma with underlying artery damage

Although epithelioid cell histiocytoma is considered a variant of fibrous histiocytoma (dermatofibroma), the histogenesis of this condition remains controversial. A recent investigation suggested the possibility that epithelioid cell histiocytoma is an angioformative fibrous histiocytoma. We report a case of epithelioid cell histiocytoma underlying a damaged artery. This epithelioid cell histiocytoma with a central area of hemorrhage was associated with a medium-sized artery in the reticular dermis running vertically up to the lesion. Both the artery in the reticular dermis and its centrally branched artery in the subcutaneous tissue showed mural injury and intraluminal epithelioid endothelial proliferation. Immunohistochemically, the labeling rate for each of the antibodies studied in the epithlioid cells was as follows: 40% for Factor XIIIa, 5% for CD34, 20% for factor VIII-related antigen, and 10% for alpha-smooth muscle cell actin. This case may support the view that epithelioid cell histiocytoma is a vascular and angioformative fibrous histiocytoma.     

Cutaneous and subcutaneous fibrohistiocytic tumors of intermediate malignancy: an update

The fibrohistiocytic tumors of intermediate malignancy are uncommon mesenchymal tumors, which typically occur in the skin and subcutis and which may pose significant problems for the dermatopathologist. This article reviews the clinical, histopathologic, and genetic features of dermatofibrosarcoma protuberans, giant cell fibroblastoma, angiomatoid (malignant) fibrous histiocytoma, plexiform fibrous histiocytoma, and soft tissue giant cell tumor (of low malignant potential). The differential diagnosis of these tumors with a variety of benign and fully malignant cutaneous soft tissue neoplasms is discussed.     

Flow-cytometric DNA analysis in cutaneous fibrohistiocytic tumors

BACKGROUND: Fibrohistiocytic tumors are rare skin tumors. There are many kinds of fibrohistiocytic tumors. It is often difficult to differentiate dermatofibrosarcoma protuberans (DFSP) and malignant fibrous histiocytoma (MFH) from dermatofibroma (DF) and other benign tumors. OBJECTIVE: In this study, the possible usefulness of DNA ploidy for the differentiation was studied. METHODS: Five MFH, 9 DFSP, 3 DF, 2 lipofibromas and 2 scars were studied for DNA ploidy using a flow cytometer. RESULTS: All the 7 benign tumors showed a diploid pattern. Of 14 malignant fibrohistiocytic tumors, 8 cases (57.1%) showed an aneuploid and 6 a diploid pattern. Two of 5 MFH (40.0%) and 6 of 9 DFSP (66.7%) showed an aneuploid pattern. These results showed that fibrohistiocytic tumors with an aneuploid pattern are malignant, though those with a diploid pattern may be benign or malignant. CONCLUSION: Analysis of DNA ploidy using flow cytometry was concluded to be useful for the differentiation of malignant fibrohistiocytic tumors from benign ones.     

Benign fibrous histiocytoma with osteoclast-like giant cells in an infant

Abstract:  Benign fibrous histiocytoma is a common soft tissue tumor that usually occurs in adults and is relatively rare in childhood. This report describes a 7-month-old Caucasian boy with an enlarging firm congenital nodule on his occipital scalp. Histologic analysis revealed a benign fibrous histiocytoma with osteoclast-like giant cells. Benign fibrous histiocytoma with osteoclast-like giant cells is a rare histologic variant.     

Dermatofibroma with diffuse eosinophilic infiltrate

Dermatofibroma, a common form of benign fibrous histiocytoma, is characterized by the presence of different cell types consisting of fibroblastic, histiocytic, and even multinucleated cells. Dermatofibromas are always accompanied by an inflammatory lymphoid cell reaction, including B cells and T cells at their border. To our knowledge, however, there is no report of an infiltration of eosinophils within this tumor. We describe a dermatofibroma on the pretibial region of an 8-year-old boy. Microscopic examination revealed a diffuse eosinophilic infiltration within the dermatofibroma, which was typically composed of histiocytic cells and mature collagen. The diagnosis of dermatofibroma was confirmed by demonstrating the immunoreactivity of tumor cells to an anti-factor XIIIa antibody.     

Dermoscopic findings of haemosiderotic and aneurysmal dermatofibroma: report of six patients

BACKGROUND: The clinical diagnosis of dermatofibroma is commonly easy. However, the differentiation of dermatofibroma from other cutaneous tumours is difficult in some instances, primarily in atypical cases and rare variants. Haemosiderotic dermatofibroma is a variant composed of numerous small vessels, extravasated erythrocytes and intra- and extracellular haemosiderin deposits. Aneurysmal dermatofibroma is a variant composed of large, blood-filled spaces without endothelial lining. Some authors consider that haemosiderotic dermatofibroma is an early stage in the development of aneurysmal dermatofibroma. The clinical differential diagnosis of haemosiderotic or aneurysmal dermatofibroma must include melanoma and other melanocytic tumours, vascular neoplasms, adnexal tumours and nonspecific cysts. Dermoscopy improves the diagnostic accuracy in pigmented and nonpigmented skin lesions. OBJECTIVES: To evaluate specific dermoscopic criteria. METHODS: Dermoscopic examination (using the DermLite Foto; 3Gen, LLC, Dana Point, CA, U.S.A.) of six patients with haemosiderotic or aneurysmal dermatofibromas was performed to evaluate specific dermoscopic criteria. RESULTS: A multicomponent pattern with a central bluish or reddish homogeneous area in combination with white structures and a peripheral delicate pigment network along with vascular structures was noted in five of six lesions. CONCLUSIONS: This dermoscopic pattern yielded the diagnosis of haemosiderotic or aneurysmal dermatofibroma in most cases. However, this multicomponent pattern may present in some melanomas and although it is useful in determining a clinical diagnosis of aneurysmal dermatofibroma, it may not be specific to this entity.     

Pedunculated hemangiopericytoma-like tumor: peculiar fibroepithelial polyp or fibrous histiocytoma variant

Abstract:  Pathologists are continually challenged with the difficult task of discriminating between innocuous disease processes and potentially malignant entities. Apropos of this concern, we present a series of three cutaneous polypoid lesions that simulated fibroepithelial polyp, yet upon close scrutiny yielded histologic features of solitary fibrous tumor (SFT) or hemangiopericytoma. These pedunculated lesions showed a storiform pattern of spindled cells with interspersed gaping vascular channels reminiscent of SFT or hemangiopericytoma. Interestingly, the immunohistochemical staining profile of these lesions was negative for CD34 and positive for bcl-2 and factor XIIIa. These findings were discordant with SFT and suggest a relationship with fibrous histiocytoma. We propose that this entity represents a hitherto described variant of fibrous histiocytoma known as pedunculated hemangiopericytoma-like fibrous histiocytoma.     

150例皮肤纤维瘤组织病理与临床分析

目的 分析皮肤纤维瘤（DF）的组织病理与临床特征,探讨两者的相互联系。方法 回顾分析2017年9月至2018年8月在上海市皮肤病医院病理科经皮肤组织病理检查确诊的150例DF患者的临床和组织病理资料。结果 150例患者中,男65例,女85例,年龄（42 ± 13.8）岁,病程3个月至 > 30年,部分有伴随症状,主要表现为瘙痒,有自发痛、轻压痛,18例皮损有外伤、虫咬或感染病史。皮损主要位于四肢（107例,71.3%）,以单发皮损为主（105例,70%）。病理检查前拟诊为“DF”102例,“表皮样囊肿”16例,“色痣”13例,“瘢痕疙瘩”3例,“皮肤肿物”12例,“恶性黑素瘤”1例,“黄色肉芽肿”1例,“结节性痒疹”1例,“神经纤维瘤”1例。在这些患者的169张苏木精-伊红染色切片中,66张（39.1%）为细胞性,36张（21.3%）硬化性,25张（14.8%）表现为动脉瘤样型DF,22张（13.0%）上皮样型。12张切片内可见两种或两种以上亚型并存的现象。还可见少数新的变异型,如DF伴汗腺导管增生（1例）、深在型DF（3例）、上皮样细胞与增生胶原相间的DF（1例）等。动脉瘤样型DF病程长短不一,7个月至> 30年,多表现为发生于下肢的皮肤肿物样损害。细胞性DF病程相对较短,常发现数月后就诊,好发于四肢,常伴痒痛。硬化性或萎缩性DF病程长,为数年或数十年,好发于上肢,多无伴随症状。上皮样型DF病程长短不一,临床表现多样,多发于下肢,无伴随症状。结论 DF的临床表现及病理表现均具有多样性,不同的DF皮损可有相似的典型组织病理学表现,不典型的病理表现可干扰疾病诊断。