Clinical, histopathological, dermatoscopic and digital microscopic features of dermatofibroma: a retrospective analysis of 200 lesions

Pediatric dermatofibromas: Truncal predominance in younger children

Pediatric dermatofibromas are considered rare in young children and have not been well characterized, often misdiagnosed clinically. We performed a retrospective case series of children younger than 18 years with histopathologically diagnosed dermatofibromas at our institutions and evaluated age at onset and diagnosis, sex, lesion location, and size, associated symptoms, change over time, and pre-biopsy diagnosis. Overall, dermatofibromas were most common on the back and chest (20/53; 38%), followed by the legs (15/53; 28%) and arms (12/53; 23%) with the most common pre-biopsy diagnosis of "cyst" (23/53; 43%), followed by dermatofibroma (16/53; 30%), and pilomatricoma (12/53; 23%). Our study reinforces previous findings of truncal predominance of pediatric dermatofibromas, different from adults.

Dermoscopy of haemosiderotic/aneurysmal dermatofibroma: A morphological study of 110 cases

BACKGROUND

Haemosiderotic and aneurysmal dermatofibromas are uncommon and frequently misdiagnosed lesions, which can be considered as different histopathological stages of the same tumour. A dermoscopic diagnosis testing accuracy has not been performed for these tumours to date.

OBJECTIVES

To determine the diagnostic significance of dermoscopic structures and patterns associated with haemosiderotic/ aneurysmal dermatofibromas in a large series.

METHODS

Dermoscopic images of histopathologically proven cases of 110 haemosiderotic/ aneurysmal dermatofibromas and 501 other tumours were collected. The frequency, sensitivity, specificity, positive predictive value and negative predictive value of the dermoscopic structures and patterns associated with these lesions were calculated.

RESULTS

Haemosiderotic/ aneurysmal dermatofibromas are mostly symmetric lesions (86.5%), and a prominent homogeneous area was present in 100% of them. The presence of vascular structures was very common (86.4%), and dotted vessels were predominant (58.2%). Shiny white structures were seen in 85.5% of lesions, while a peripheral delicate pigment network was present in 69.1%. The most significant pattern was the one composed of a prominent homogeneous area and peripheral delicate pigment network, which showed a specificity of 100% with a relatively good sensitivity (69.1%). All the patterns containing a peripheral delicate pigment network showed very good specificities, positive predictive values and negative predictive values. Those patterns without a peripheral delicate pigment network showed the highest sensitivities, but they showed a significant overlap with other tumours, mainly with melanoma.

CONCLUSIONS

Dermoscopy is helpful in improving the diagnostic accuracy of haemosiderotic/ aneurysmal dermatofibromas. However, there is a considerable dermoscopic overlap between these tumours and melanoma, specifically when the peripheral delicate pigment network is absent.

Clinicopathologic Features of Facial Dermatofibromas, a Cohort Study, and a Systematic Review of Literature

BACKGROUND

Dermatofibromas are common skin tumors that typically occur on the extremities and trunk and demonstrate benign behavior, frequent recurrences, and very rare metastasis. Facial dermatofibromas are rare and not well studied . We analyzed clinicopathologic features of facial dermatofibromas.

DESIGN

Considering the rarity of the condition, we conducted a cohort study and a systematic review. We queried medical records of a single tertiary care center for dermatofibromas from January 1, 2000, to July 1, 2021. A systematic review of multiple databases was conducted through October 27, 2021, to include studies reporting facial dermatofibromas. Random-effects meta-analysis was used to estimate pooled odds ratio and proportions with associated 95% confidence interval (CI).

RESULTS

The cohort study identified 2858 cases of dermatofibromas, of which, 23 cases from 18 patients were on the face (1%). The mean age was 52.7 ± 17.8 years. Fifty-six percent of the cases were women. The most common location was the forehead (6 cases). The mean follow-up was 54 months. Forty-four percent of the cases had subcutaneous involvement, and 39% were the cellular type. Margins were positive in 89% of the cases, recurrence rate was 22%, and no metastases were observed. The systematic review included 10 studies (119 patients). Meta-analyses showed that facial dermatofibromas were 2% of all dermatofibromas (95% CI: 1%-3%). The local recurrence rate was 14% (95% CI: 6%-26%). Facial dermatofibromas with subcutaneous involvement were more likely to recur [odds ratio 4.53 (95% CI: 1.12-18.24)]. Before histopathologic examination, clinical differential diagnosis included dermatofibromas in only 9% of the cases (95% CI: 2%-19%).

CONCLUSION

Facial dermatofibromas are rare and are difficult to fully excise. Cellular type and subcutaneous or muscular involvement are common in these cases and tend to have higher local recurrence rate than other nonfacial dermatofibromas. Wider excisions might be necessary for complete excision.

Hemosiderotic dermatofibroma mimicking melanoma: A case report and review of the literature

Hemosiderotic dermatofibroma (HDF) often mimics melanoma clinically. A definite diagnosis relies on histopathological evaluation and immunohistochemistry. As it can progress to aneurysmal dermatofibroma (ADF), complete excision is recommended.

Features of dermatofibroma in reflectance confocal microscopy

BACKGROUND

Dermatofibroma (DF) is a common benign skin lesion in a majority of cases located on the legs or upper limbs. The etiology of DF is still unclear.

OBJECTIVES

Reflectance confocal microscopy features of DF were described.

METHODS

Forty patients with DF diagnosis confirmed by dermoscopy were examined using reflectance confocal microscopy VivaScope 1500 from March 2018 to April 2019.

RESULTS

DF was more common in females (80%) than males (20%). Thirty-six lesions (90%) were located on the limbs while four (10%) were on the trunk. Dermoscopically, 18 lesions (45%) revealed typical features: central white area with a brown network in the periphery. Twenty-two DFs (55%) were found with a central white patch and globular-like structures, surrounded by a thin brown network. In reflectance confocal microscopy, all revealed a typical honeycombed pattern, although in some cases (30%), streaming was observed. In two lesions (5%) in epidermis, few dendritic cells were observed, and one DF revealed roundish pagetoid cells (2.5%). The dermoepidermal junction (DEJ) in all lesions was abounded in dilated vessels. The most common observable feature of DF was bright "rings" composed of monomorphic, regular cells surrounding dark dermal papillae. In five lesions (12.5%), rings were "double" because of exceptionally pigmented DF.

CONCLUSION

Reflectance confocal microscopy enables us to describe microscopic features of DF. There are four confocal microscopic features observable in each DF: in the epidermis, normal honeycombed pattern, sometimes with local streaming, in DEJ, edged papillae, bright rings, and dilated vessels.

High-frequency ultrasound in the diagnosis of selected non-melanoma skin nodular lesions

Introduction

Ultrasonographic examination is commonly used in an outpatient setting, possibly due to its low cost, low risk for patients and the possibility to obtain real time images. Typically used heads have the frequency ranging from 7.5 to 12 MHz. Higher frequencies ensure higher resolution, yet they are limited by the penetration depth – reaching from several to several tens of millimetres into the skin. High-frequency ultrasonography (HFUS) appears to be a promising method for the detection and differential diagnostics of selected nodular skin lesions.

Aim

The study aimed at a comparison of the data obtained by using HFUS, histopathological and dermatoscopic images of selected skin lesions to determine their common features.

Material and methods

Nodular lesions classified as potentially malignant were subjected to clinical, dermatoscopic and high-frequency ultrasonographic examinations. Then the patients were referred for surgical removal with histopathological assessment.

Results

A total of 54 nodular lesions were examined, out of which 34 were diagnosed as non-melanoma. The most common lesions were melanocytic naevi dermatofibroma, nodular basal cell carcinoma and pyogenic granuloma. Other examined lesions included blue naevus, seborrheic wart, xanthogranuloma juvenile and Spits naevus. In all lesions except Spitz naevus, HFUS images corresponded at least with dermatoscopic or histopathology images.

Conclusions

HFUS can be used as a supporting diagnostic tool ensuring better pre-operative proceedings. HFUS is a non-invasive, easy and inexpensive screening method for the determination of different skin cancers as it provides valuable information allowing to determine the cutting margins and lesion shape.

PDGFB Rearrangements in Dermatofibrosarcoma Protuberans of the Vulva: A Study of 11 Cases Including Myxoid and Fibrosarcomatous Variants

Dermatofibrosarcoma protuberans (DFSP) is a low-grade fibroblastic sarcoma that tends to arise in young to middle age adults and involve the trunk and proximal extremities. Rare examples of vulvar DFSP have been reported, including myxoid, myoid, and fibrosarcomatous variants, but detection of the characteristic t(17;22)(q22;q13) that produces COL1A1-PDGFB gene fusion has not been evaluated in a large series of primary vulvar tumors. The clinical, morphologic, immunohistochemical, and molecular cytogenetic features of 11 cases were examined. Patient age ranged from 29 to 75 yr (mean, 46 yr; median, 43 yr). Seven tumors were purely classic DFSP, 1 was purely myxoid DFSP and the remaining 3 had varying quantities of fibrosarcomatous DFSP. All cases of classic DFSP had diffuse expression of CD34 and low-level p53 immunoreactivity. Myxoid variants had strong, but reduced expression of CD34. Fibrosarcomatous DFSP showed focal CD34 expression and increased p53 reactivity. Nine of 11 tumors (82%) had rearrangement of PDGFB by fluorescence in situ hybridization. The 2 nonrearranged tumors were a classic DFSP and a myxoid DFSP with fibrosarcomatous transformation. Follow-up was available for 9 patients (82%) and ranged from 1 to 108 mo (mean, 30 mo; median, 21 mo). Eight patients had tumors with positive margins, one of which developed local recurrence after no further therapy. No patient developed metastasis. The high frequency of PDGFB rearrangement in vulvar DFSP provides a useful exploit in diagnostically challenging cases and genetic evidence of probable clinical response to targeted therapeutics in cases of locally advanced or metastatic tumors.

Dermatofibroma: sonographic findings and pathologic correlation

Background Ultrasound has been increasingly used for the evaluation of superficial soft tissue lesions. Dermatofibroma is one of the most common dermal lesions. Experiences in ultrasound examinations of dermatofibromas have been accumulated. Purpose To evaluate sonographic findings of dermatofibroma and to correlate them with pathologic findings. Material and Methods A total of 18 dermatofibromas in 15 patients were included. Sonographic findings were assessed for location, depth, size, shape, margin, spiculation, echogenicity, internal hyperechoic dots, change in echogenicity of adjacent soft tissue, and vascularity, by two musculoskeletal radiologists in consensus. Pathologic findings were evaluated by one pathologist. Ultrasonographic characteristics were correlated with the pathologic findings by discussion between one radiologist and one pathologist. Results On ultrasound, all lesions were found to be located in the dermis, and 14 lesions (78%) extended into the subcutaneous layer. Mean size was 7 mm (range = 3 to 10 mm). Characteristic findings were ill-defined margins (n = 15, 83%), spiculated margins (n = 12, 67%), change in echogenicity of adjacent soft tissue (n = 14, 78%), and no Doppler flow (n = 14, 78%). Histologically, depth, margin, and spiculation were correlated with sonographic findings. Reactive fibrosis and chronic inflammation were seen in adjacent dermis and subcutaneous fat layer of echogenicity change. Conclusion On ultrasound, dermatofibromas are usually visible as avascular dermal lesions with extension into the subcutaneous layer, and are characterized by ill-defined margins, marginal spiculation, and change in echogenicity of surrounding soft tissues.