Penvadee Pattanaprichakul

Utility of BRAF V600E Immunohistochemistry Expression Pattern as a Surrogate of BRAF Mutation Status in 154 Patients with Advanced Melanoma

Successful BRAF inhibitor therapy depends on the accurate assessment of the mutation status of the BRAF V600 residue in tissue samples. In melanoma, immunohistochemical (IHC) analysis with monoclonal anti-BRAF V600E has emerged as a sensitive and specific surrogate of BRAF V600E mutation, particularly when BRAF V600E protein expression is homogeneous and strong. A subset of melanomas exhibit heterogeneous labeling for BRAF V600E, but our understanding of the significance of heterogeneous BRAF V600E IHC expression is limited. We used next-generation sequencing to compare BRAF V600E IHC staining patterns in 154 melanomas: 79 BRAF(WT) and 75 BRAF (including 53 V600E) mutants. Agreement among dermatopathologists on tumor morphology, IHC expression, and intensity was excellent (ρ = 0.99). A predominantly epithelioid cell phenotype significantly correlated with the BRAF V600E mutation (P = .0085). Tumors demonstrating either heterogeneous or homogeneous IHC expression were significantly associated with the BRAF V600E mutation (P < .0001), as was increased intensity of staining (P < .0001). The positive predictive value was 98% for homogenous IHC expression compared with 70% for heterogeneous labeling. Inclusion of both heterogeneous and homogeneous BRAF V600E IHC expression as a positive test significantly improved IHC test sensitivity from 85% to 98%. However, this reduced BRAF V600E IHC test specificity from 99% to 96%. Cautious evaluation of heterogeneous BRAF V600E IHC expression is warranted and comparison with sequencing results is critical, given its reduced test specificity and positive predictive value for detecting the BRAF V600E mutation.

An unusual case of eumycetoma caused by Exophiala jeanselmei after a sea urchin injury

Penvadee Pattanaprichakul, Sumanas Bunyaratavej, Charussri Leeyaphan, Panitta Sitthinamsuwan, Montarop Sudhadham, Chanai Muanprasart, Peiying Feng, Hamid Badali and G. Sybren de Hoog Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok Thailand, Department of Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand, Department of Biology, Faculty of Science and Technology, Suansunandha Rajabhat University, Bangkok, Thailand, Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China, Department of Medical Mycology and Parasitology ⁄ Invasive Fungi Research Centre (IFRC), School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran and CBS-KNAW Fungal Biodiversity Centre, Utrecht, The Netherlands

Melanocytic matricoma: two cases of a rare entity in women

Melanocytic matricoma is a rare cutaneous adnexal tumor occurring in humans with only 13 cases reported in the literature. The typical lesion is a circumscribed pigmented nodule on sun‐damaged skin. Most cases have occurred in elderly men. The tumor contains a mixed population of matrical cells, supramatrical cells, shadow or ghost cells, and dendritic melanocytes. We report two cases of melanocytic matricoma in two elderly women with unusual histopathological features such as cystic degeneration and focal granulomatous inflammation, which are considered to be atypical for this entity.

Tender cutaneous nodules of the legs: diagnosis and clinical clues to diagnosis.

Background  “Tender cutaneous nodules of the legs” is a common manifestation in dermatology. Histopathological investigation is usually required for this condition, because clinical data are frequently insufficient to make a definite diagnosis.

Random Skin Biopsy in the Diagnosis of Intravascular Lymphoma

Random skin biopsy (RSB) is a method for diagnosis of intravascular lymphoma (IVL). However, the indications for RSB to diagnose IVL have not yet been established. The aim of this study was to determine the appropriate indications for RSB to diagnose IVL.

Thermal Response of In Vivo Human Skin to Fractional Radiofrequency Microneedle Device

Background. Fractional radiofrequency microneedle system (FRMS) is a novel fractional skin resurfacing system. Data on thermal response to this fractional resurfacing technique is limited. Objectives. To investigate histologic response of in vivo human skin to varying energy settings and pulse stacking of a FRMS in dark-skinned subjects. Methods. Two female volunteers who were scheduled for abdominoplasty received treatment with a FRMS with varying energy settings at 6 time periods including 3 months, 1 month, 1 week, 3 days, 1 day, and the time immediately before abdominoplasty. Biopsy specimens were analyzed using hematoxylin and eosin (H&E), Verhoeff-Van Gieson (VVG), colloidal iron, and Fontana-Masson stain. Immunohistochemical study was performed by using Heat Shock Protein 70 (HSP70) antibody and collagen III monoclonal antibody. Results. The average depth of radiofrequency thermal zone (RFTZ) ranged from 100 to 300 μm, correlating with energy levels. Columns of cell necrosis and collagen denaturation followed by inflammatory response were initially demonstrated, with subsequent increasing of mucin at 1 and 3 months after treatment. Immunohistochemical study showed positive stain with HSP70. Conclusion. A single treatment with a FRMS using appropriate energy setting induces neocollagenesis. This wound healing response may serve as a mean to improve the appearance of photodamaged skin and atrophic scars.

Halo Nevus Versus Melanoma with Regression

Halo nevus is a distinctive benign melanocytic nevus that occurs predominantly in childhood and adolescence. Clinically, the nevus has a depigmented halo around the centrally brown or black macule, papule, or nodule. Histologically, the clusters of nevus cells are obscured by an at least dense lymphocytic infiltrate. In some lesions of halo nevus, the melanocytes may show variable degree of cellular atypia and thus may be mistaken for a melanoma with lymphocytic infiltrate or with regression. Therefore, pathologists should be aware of this benign inflammatory condition involving melanocytic lesions as to avoid the misdiagnosis of regressing melanoma.

Reticulate hyperpigmentation in systemic sclerosis: a case report and review of the literature

IntroductionSystemic sclerosis is a systemic connective tissue disease with variable cutaneous presentations. Although pigmentary disturbances have been described in systemic sclerosis, a reticulate hyperpigmentation has only been reported in one case of systemic sclerosis to date.Case presentationWe describe a previously healthy 51-year-old Thai woman who presented with a reticulate hyperpigmentation affecting her trunk and extremities, together with sclerodactyly and proximal sclerosis, resulting in a new diagnosis of systemic sclerosis.ConclusionsTo date, the pathogenesis of reticulate hyperpigmentation in systemic sclerosis remains unclear. Increased melanin synthesis and altered thermoregulatory mechanism are proposed to be involved in the pathogenesis of this presentation. This case represents an unusual cutaneous feature of reticulate hyperpigmentation in the setting of systemic sclerosis.

Prevalence and Clinical Correlation of Superficial Fungal Foot Infection in Thai Naval Rating Cadets

Background Superficial fungal foot infection is one of the most important dermatological diseases currently affecting military personnel. Many Thai naval rating cadets are found to suffer from superficial fungal foot infections and their sequels. Objective To investigate prevalence, potent risk factors, responding pathogens and clinical correlation of superficial fungal foot infection in Thai naval rating cadets training in Naval rating school, Sattahip, Thailand. Materials and Methods This cross-sectional study was performed in August 2015. Validated structured questionnaire was used regarding information about behaviors and clinical symptoms. Quality of life was assessed by Dermatology Quality of Life Index (DLQI) questionnaire and clinical presentation demonstrated by Athletes foot severity score (AFSS). Laboratory investigations including direct microscopic examination and fungal culture were performed and recorded. All of the participants were informed and asked for their consent. Results A total of 788 Thai naval rating cadets with a mean age of 19 yr were enrolled. There were 406 (51.5%) participants suspected of fungal skin infection from questionnaire screening. After clinical examination, 303 participants (38.5%) were found to have foot lesions (AFSS ≥1). Superficial fungal foot infection was diagnosed with microscopic examination and fungal culture in 57 participants, giving a point prevalence of 7.2%. Tinea pedis was diagnosed in 54 participants with the leading causative organism being Trichophyton mentagrophytes (52.8%). Other 3 participants were diagnosed as cutaneous candidiasis. Wearing combat shoes more than 8 h was found to be a predisposing factor (p = 0.029), taking a shower less than two times a day (p = 0.008), and wearing sandals during shower (p = 0.055) was found to be protective against infection. Most fungal feet infection cases noticed their feet abnormalities (p < 0.001) including scales (p < 0.001), vesicles (p = 0.003) and maceration at interdigital web spaces (p < 0.001). Mean DLQI in superficial fungal foot infection cases was 3.35. Participants who had foot lesions (AFSS ≥1) were concerned of their foots unpleasant odor demonstrated significantly higher mean DLQI than those without odor (4.2 vs. 2.28; p < 0.001). Conclusion Superficial fungal foot infection is found as 7.2% of naval rating cadets. Wearing combat shoes more than 8 h was found to be a predisposing factor. In addition to skin manifestations including scales, vesicles, and maceration, superficial fungal foot infection also exhibited an unpleasant foot odor which affected quality of life. Self-foot-examination and life style modification should be promoted to prevent fungal infection.

Interobserver reliability of histopathological features for distinguishing between cutaneous polyarteritis nodosa and superficial thrombophlebitis

Interobserver reliability of histopathological features in differentiation between cutaneous polyarteritis nodosa (cPAN) and superficial thrombophlebitis (ST) by assessment of inter‐rater agreement of five histological features was investigated.