A case of cutaneous variant of intravascular large B-cell lymphoma in which dermoscopy revealed telangiectasias associated with erythematous induration.

Intravascular large B-cell lymphoma (IVLBCL) is a rare type of extranodal, diffuse, large B-cell lymphoma characterized by the selective growth of lymphoma cells within the lumen of small blood vessels, with no lymphadenopathy or masses. Herein, we report a cutaneous variant of IVLBCL that is rare in Asia. A healthy 73-year-old Japanese woman presented to our hospital with painful erythematous indurations and telangiectasia of the lower extremities, which was confirmed on dermoscopy. Physical examination revealed no systemic involvement, and laboratory parameters were within normal ranges. No abnormal fluorodeoxyglucose (FDG) uptake was detected on 18FDG positron emission tomography/computed tomography. Histopathological examination revealed proliferation and dilatation of blood vessels in the subcutis layer, occluded by CD20-positive atypical lymphoid cells. Thus, the patient was diagnosed with a cutaneous variant of IVLBCL without systemic symptoms. In conclusion, it is important to confirm telangiectasia using dermoscopy and perform skin biopsies in patients presenting with sudden-onset erythematous induration.

Applications of Ultraviolet and Sub-ultraviolet Dermatoscopy in Neoplastic and Non-neoplastic Dermatoses: A Systematic Review.

Dermatoscopy is a non-invasive and cost-efficient imaging technique augmenting clinical examination in neoplastic and non-neoplastic dermatoses. Recently, novel dermatoscopic techniques based on principles of reflectance/absorption and excited fluorescence have been developed. However, comprehensive data on their applications are sparse, and terminology is inconsistent. In this systematic review, we addressed the principles of ultraviolet (UV) imaging and proposed categorization based on spectral characteristics and signal acquisition, as well as discussed documented and potential clinical applications, safety measures during examination, and limitations associated with reflectance and fluorescence dermatoscopy. A literature search was conducted in the PubMed medical database until 2 December 2023 according to PRISMA guidelines, and 28 papers fit the scope of this review, whereas additional relevant articles were included to provide broader context regarding the chosen terminology, chromophores described, safety of sub-UV/UV, and regulations for light-emitting devices. UV and sub-UV dermatoscopy, categorized into different methods on the basis of the emitted wavelength and signal acquisition process (reflectance versus fluorescence), augment conventional dermatoscopy by optimizing safety margins in melanoma, facilitating early detection of tumor recurrence, and enhancing visualization in non-neoplastic conditions, including pigmentation disorders, intertrigo, papulo-desquamative dermatoses, and beyond. The review highlights the limitations of these techniques, including difficulty in differentiating melanin from hemoglobin, challenges in evaluating uneven surfaces, and artifacts. Although UV dermatoscopy complements conventional dermatoscopy, clinicians should be aware of their peculiarities, artifacts, limitations, and safety concerns to optimize their diagnostic accuracy and ensure patient's safety.

Erythematous reactions to two ultraviolet excimer therapy devices with different irradiance levels: Reconsidering the reciprocity law.

BACKGROUND: Few studies have examined the effectiveness of the reciprocity law in ultraviolet excimer therapy. This study aimed to examine the difference in erythematous reaction in human skin when the irradiance of ultraviolet excimer treatment devices differed while the irradiation dose was constant. MATERIALS AND METHODS: This study, conducted at the Department of Dermatology, Chiba University, included 15 healthy adults aged 20-65 years (mean age, 46.3 years; seven men). Using ultraviolet excimer treatment devices with different irradiances (50 or 150 mW/cm2 ), the upper abdomen of each participant was irradiated with ultraviolet light at set irradiation doses (80, 100, 120, 140, 160, 180, and 200 mJ/cm2 ). The erythema index of each irradiated site was measured using a melanin- and erythema-measuring device, and the difference in erythema index before and 24 h after irradiation was the primary endpoint. RESULTS: The change in erythema index was significantly higher for an irradiance of 150 mW/cm2 . Significant differences (p < 0.05) were observed between these irradiance levels at irradiation doses of 100-200 mJ/cm2 . CONCLUSIONS: Even for the same irradiation dose, stronger erythematous reactions occurred at higher irradiances in ultraviolet excimer treatment. This suggests that the reciprocity law may not always hold true in excimer therapy.

Assessment of malignant melanoma lesions using violet-light dermoscopy: A case report.

Malignant melanomas often present with irregular shapes and in multiple shades of brown under white light. Dermoscopy is used to diagnose malignant melanomas; nevertheless, it is often difficult to differentiate malignant melanoma from healthy pigmented skin. The DZ-D100 dermoscope (Casio Computer) is a digital camera equipped with a white light-emitting diode (LED) and a violet LED, which can capture non-polarized/polarized conventional dermoscopy images (CDS) as well as violet-light dermoscopy (VLD) images. Since the absorption wavelength of melanin approaches that of ultraviolet rays, VLD with a wavelength of 405 nm can be used to visualize it. This camera allows three images with the same composition to be captured simultaneously. In this case, we performed dermoscopy with DZ-D100 to determine the surgical resection margins of a melanoma of the heel in a 76-year-old woman. The pale-colored lesions that were difficult to demarcate by CDS were clearly visible by VLD, presenting as dark areas in the grayscale images. Preoperatively determined lesion boundaries with CDS in combination with VLD were histologically more accurate than those with conventional CDS alone. Therefore, the combination of CDS and VLD may reveal the distribution of subtle pigmentation of fine melanin in the skin, making it easier to distinguish between lesions and healthy skin. As one of the limitations, parts of the heel with thick stratum corneum were also observed to be dark gray in the VLD images. Therefore, the evaluation of pigment lesion should be performed by comparing both CDS and VLD.

Ungual seborrheic keratosis with longitudinal melanonychia: A case report.

In this paper, we report the case of a 71-year-old man with an 8-year history of melanonychia on the right little finger, who referred to our hospital because the color of pigmented area had gradually darkened and the width had expanded. Physical examination revealed longitudinal melanonychia with brown color (4 mm in width). Dermoscopic examination revealed multiple white round clods and splinter hemorrhages. No micro-Hutchinson sign was observed. We performed a punch biopsy (diameter 3 mm) of the nail matrix for diagnosis. Histopathological examination revealed irregular acanthosis of epithelium of the nail bed and distal matrix, which consisted of basaloid cells without nuclear atypia. Several zones exhibited cell whorls reminiscent of squamous eddies. The whorls were composed of large pink cells arranged in an onion peel-like fashion. The basaloid cells tested negative for human papillomavirus in situ hybridization and p16 staining. The morphology of white round clods (milia-like cysts in metaphoric term) observed in dermoscopic analysis corresponded to squamous eddies in histopathology. Considering these features, ungual seborrheic keratosis (SK) with longitudinal melanonychia was diagnosed, which is an atypical site for SK. We suggest that the dermoscopic finding of milia-like cysts may be useful for the diagnosis of ungual SK.

Five novel mutations in SASH1 contribute to lentiginous phenotypes in Japanese families.

SASH1 has been reported as a causal gene of lentiginous phenotypes with and without heredity, including an autosomal dominant type characterized by lentigines predominantly on sun-exposed areas such as the face and limbs. Recently, cases of dyschromatosis with SASH1 mutations have been reported worldwide; however, only one case has been reported from Japan. Here, we analyzed six Japanese patients who characteristically showed many lentigines on sun-exposed areas, using next-generation sequencing. We identified five novel heterozygous mutations in SASH1 (p.I586M, p.S531Y, p.R644W, p.T525R, and p.S516I) in our patients and their families. The p.R644W substitution identified in two unrelated families was the first mutation located in the sterile alpha motif 1 (SAM1) domain. The degree and location of the lentigines were variable across individuals, even if they shared the same SASH1 mutation. All mutations were predicted to be deleterious by six different algorithms used to evaluate the functional impact of a variation. In addition, immunohistopathological findings and RNA sequencing results suggested that SASH1 mutations were associated with an increase in the number of melanocytes, acceleration of melanogenesis, and upregulated hair keratin expression.

Usefulness of 2-D shear wave elastography for the diagnosis of inguinal lymph node metastasis of malignant melanoma and squamous cell carcinoma.

We used 2-D shear wave elastography to quantify lymph node hardness, from the shear wave velocity, to determine the presence or absence of metastatic lymphadenopathy in the inguinal lymph nodes of five patients with malignant melanoma and squamous cell carcinoma. The shear wave velocity accurately identified all cases of metastasis confirmed by histology, compared with two false-positive and one false-negative finding with positron emission tomography/computed tomography. 2-D shear wave elastography would be useful to evaluate inguinal lymph node metastasis.

Differences in dermoscopic findings between early and mature clear cell acanthoma.

Clear cell acanthoma (CCA) is a rare benign epidermal tumor that is difficult to diagnose by visual inspection. Conversely, its diagnosis by dermoscopy is relatively easy owing to the characteristic serpiginous arrangement of coiled vessels, sometimes described as the "string-of-pearls" formation. However, in few published reports, the dermoscopic diagnosis of mature CCA has been reported. Here, we report the histopathological and detailed dermoscopic findings of two CCA cases. Between these, one case was of early (~6 months) CCA exhibiting the characteristic vascular string-of-pearls formation, whereas the other was of a more mature (~10 years) CCA; although the latter case showed combined thick and thin white intersecting lines with large coiled vessels and/or red clods, it had the string-of-pearls formation. Thus, regardless of CCA maturity, the string-of-pearls formation was present. We propose that the combination of combined thick and thin white intersecting lines along with the vascular string-of-pearls formation reflecting large coiled vessels and/or red clods on dermoscopy is a diagnostic clue to mature CCA.

Review of vasculature visualized on dermoscopy.

Dermoscopy is a useful tool for finding and screening skin tumors, especially skin cancers. It is well known that it is useful to diagnose pigmented tumors, such as melanocytic lesions. In recent years, after the publication of a revised two-step algorithm in 2010, dermoscopy gradually has been used to diagnose non-pigmented or non-melanocytic lesions based on their vascular structures. Some skin lesions have specific vascular structures that aid in diagnosis. In this review, I discuss the various patterns of the vascular structures and their distribution, focusing on their clinical importance and usefulness in daily medical treatment.

Dermoscopy of keratosis follicularis squamosa.

Although the characteristic clinical appearance and the differences in distribution, it is often difficult to differentiate keratosis follicularis squamosa (Dohi) from other keratotic disorders. Here, we describe the case of a 5-year-old boy with Dohi in the first time that by using dermoscopy. Dermoscpoy of the lesion showed typical lotus leaves on the water appearance and follicular plug in the center. We reported the usefulness of dermosocopy in Dohi.