Sung Ku Ahn

Yonsei University Hospital, Sŏul, Seoul, South Korea

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Publications (115)235.09 Total impact

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    Jaewoong Choi · Noo Ri Lee · Jin Wook Lee · Sung Ku Ahn

    Preview · Article · Dec 2015 · Annals of Dermatology
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    ABSTRACT: Congenital melanocytic nevus (CMN) is a neural crest-derived hamartoma, which appear at or soon after birth. CMN has a dynamic course and may show variable changes over time, including spontaneous involution. Spontaneous involution of CMN is a rare phenomenon and is often reported in association with halo phenomenon or vitiligo. The mechanism of halo phenomenon is yet to be investigated but is suggested to be a destruction of melanocytes by immune responses of cytotoxic T cells or IgM autoantibodies. Here, the authors report an interesting case of spontaneously regressed medium-sized CMN with halo phenomenon and without vitiligo, which provides evidence that cytotoxic T cells account for the halo formation and pigmentary regression of CMN.
    No preview · Article · Nov 2015 · The American Journal of dermatopathology
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    Dong In Keum · Hannah Hong · Sang-Hoon Lee · Sung Ku Ahn

    Preview · Article · Aug 2015 · Annals of Dermatology
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    Bo-Kyung Kim · Sung Ku Ahn

    Preview · Article · Aug 2015 · Annals of Dermatology
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    ABSTRACT: Even with the widespread clinical use of cannabinoid receptor (CBR) stimulating compounds, such as palmitoylethanolamine, the role of CBR agonists on inflammatory skin diseases is not yet fully understood. This study was performed to investigate the effects of CBR agonists on skin inflammation, using acute and chronic inflammation animal models. The effectiveness of the newly synthesized cannabinoid receptor 1 (CB1R) agonists was determined using in vitro assays. Markers for epidermal permeability barrier function and skin inflammation were measured, and histological assessments were performed for evaluation. Topical application of CB1R-specific agonist significantly accelerated the recovery of epidermal permeability barrier function and showed anti-inflammatory activity in both acute and chronic inflammation models. Histological assessments also confirmed the anti-inflammatory effects, which is consistent with previous reports. All of the results suggest that topical application of CB1R-specific agonist can be beneficial for alleviating the inflammatory symptoms in chronic skin diseases, including atopic dermatitis. © 2015 The International Society of Dermatology.
    No preview · Article · Jun 2015 · International journal of dermatology

  • No preview · Article · May 2015 · Journal of the American Academy of Dermatology
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    ABSTRACT: Cutaneous mucinoses are a heterogeneous group of disorders characterized by an abnormal amount of mucin in the skin. However, the pathomechanism of an excessive mucin deposition in the skin is still unknown. Eczematous dermatitis is sub-classified histologically into acute, subacute, and chronic variants. The characteristic histopathologic findings for chronic eczema are variable. However, periadnexal mucin deposition is not known as a feature of chronic eczema. To evaluate the presence of periadnexal mucin deposition in chronic eczematous dermatitis. We analyzed the skin biopsy specimens from 36 patients who were pathologically diagnosed with chronic eczematous dermatitis. Alcian blue, colloidal iron, and periodic acid-Schiff stains were used to evaluate the mucin deposition in histologic sections. Two dermatologists and two dermatopathologists evaluated the degree of mucin deposition using a 4-point scale. Various amounts of mucin deposition were observed in the periadnexal area of patients who were diagnosed with chronic eczema. Mucin deposition was more visible after staining with mucin-specific stains. Evaluation of the staining analysis scores revealed that the staining intensities were significantly higher in patients with chronic eczema than age- and site-matched controls (normal, acute to subacute eczema, and psoriasis vulgaris). Periadnexal mucin (secondary mucinoses) may be an additional finding of chronic eczematous dermatitis.
    Preview · Article · Apr 2015 · Annals of Dermatology
  • Jiwon Gye · Sung Ku Ahn · Ji-Eun Kwon · Seung-Phil Hong
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    ABSTRACT: Nonmelanoma skin cancers are caused mainly by prolonged ultraviolet (UV) exposure. There is a growing interest in the prevention of skin cancer and antiaging treatment because of aging of the population. Currently, ablative fractional photothermolysis (FP) laser treatment is actively being performed for facial rejuvenation. The objective of this study was to prove the suppressive effect of CO2 fractional laser (FL) on skin cancer development. Two groups of hairless mice were treated with either CO2 FL or nothing at 3-week intervals during the 20 weeks of UV exposure period. The number of tumors was subsequently counted every 2 weeks over the 30-week period to the termination of the experiment. At 30 weeks, representative tumors were evaluated for tumor type. The authors also determined the messenger RNA (mRNA) expression levels of the matrix metalloproteinase 13 (MMP-13) and Type 1 procollagen. At 30 weeks, the UV- and FL-treated group showed a significantly lower tumor occurrence rate and a more benign progression of tumors than the UV-only treated group. The UV- and FL-treated group presented a higher mRNA level of Type 1 procollagen and a lower level of MMP-13 than the UV-only treated group. The occurrence of UV-induced skin tumors can be decreased by multiple sessions of ablative FP with CO2 laser.
    No preview · Article · Mar 2015 · Dermatologic Surgery
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    Sang-Yeon Park · Hyun Jung Kim · Sung Ku Ahn

    Preview · Article · Apr 2014 · Annals of Dermatology
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    Preview · Article · Nov 2013 · Annals of Dermatology
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    Preview · Article · Nov 2013 · Annals of Dermatology
  • Hyunjoong Jee · Noo Ri Lee · Sung Ku Ahn
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    ABSTRACT: Reports of seborrheic keratosis (SK) with concurrent malignant tumors are rare, but previous and recent reports - especially the co-manifestation of basal cell carcinomas (BCC) have added to the ongoing debate of the possibility of the development of BCC from SK. We report a rare case of SK with underlying BCC with scarcely accounted histopathological characteristics - reticulated type and nodular type, respectively - that showed no direct histological link between the two entities. We also carefully suggest that differences in histopathology (whether the two lesions are connected or not) may account for the possibility of incidental co-habitation.
    No preview · Article · Aug 2013 · The Journal of Dermatology
  • Na Young Yoon · Sung Ku Ahn · Seung Phil Hong

    No preview · Article · Jun 2013 · International journal of dermatology
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    ABSTRACT: Despite the increasing use of topical tacrolimus, there is little information about its effect on skin wound healing. To determine effects on acute cutaneous wound healing, two full-thickness skin wounds were imparted on the backs of 45 hairless mice, which were then divided into vehicle-, topical tacrolimus- and topical steroid-treated group. Each drug was topically applied once daily. The wound area was assessed by using dermoscopic images every two days after wounding. At 3, 7 and 11 days after wounding, 10 wounds in each group were collected for semi-quantitative analysis of histological features including re-epithelialization, polymorphonuclear leucocytes, fibroblasts and collagen. We also checked the mRNA expression levels of EGF, TGF-β, TNF-α and IL-1α. While topical application of clobetasol propionate was found to delay re-epithelialization and infiltration of polymorphonuclear leucocyte, topical treatment with tacrolimus showed patterns similar to that of the vehicle. In the tacrolimus-treated group, mRNA expression levels of IL-1α and TGF-β were slightly decreased, while the others were similar with the vehicle-treated group. Unlike steroid, topical tacrolimus, therefore, did not disturb the wound healing process in a murine skin wound model.
    Preview · Article · May 2013 · Experimental Dermatology
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    ABSTRACT: Topical steroid treatment induces diverse local Wand systemic adverse effects. Several approaches have been tried to reduce the steroid-induced adverse effects. Simultaneous application of physiological lipid mixture is also suggested. Novel vehicles for topical glucocorticoids formulation were evaluated for the efficacy of reducing side-effects and the drug delivery properties of desonide, a low potency topical steroid. Transcutaneous permeation and skin residual amount of desonide were measured using Franz diffusion cells. The anti-inflammatory activity was evaluated using murine model. Topical steroids formulation containing desonide, in either cream or lotion form, were prepared using multi-lamellar emulsion (MLE), and conventional desonide formulations were employed for comparison. MLE formulations did not affect the anti-inflammatory activity of the desonide in phobol ester-induced skin inflammation model, compared with conventional formulations. While the penetrated amounts of desonide were similar for all the tested formulations at 24 hours after application, the increased lag time was observed for the MLE formulations. Interestingly, residual amount of desonide in epidermis was significantly higher in lotion type MLE formulation. Steroid-induced adverse effects, including permeability barrier function impairment, were partially prevented by MLE formulation. Topical desonide formulation using MLE as a vehicle showed a better drug delivery with increased epidermal retention. MLE also partially prevented the steroid-induced side effects, such as skin barrier impairment.
    Full-text · Article · Feb 2013 · Annals of Dermatology
  • Hae-Jin Lee · Sung Ku Ahn · Seung Phil Hong · Hana Bak

    No preview · Article · Dec 2012 · International journal of dermatology
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    Jae-Hong Kim · Hwa-Young Park · Sung Ku Ahn
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    ABSTRACT: Nevus sebaceous (NS) is a type of classical nevus or congenital malformation that is often present at birth and commonly involves the scalp or face. The lesion usually presents as a linear, yellow, hairless, and verrucous plaque. It has been well-established that several benign and malignant tumors can develop from the NS; however, there have been no reports about ectopic fat cells in the dermis, and cornoid lamella arising from the NS. We report a case of NS on the scalp with accompanying unusual histopathologic findings.
    Preview · Article · Oct 2011 · Annals of Dermatology
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    ABSTRACT: A mucocele is a common, benign lesion of the oral cavity that develops following the extravasation or retention of mucous from a major or minor salivary gland. A pyogenic granuloma (PG) is also a common, benign condition characterized by proliferating capillaries that affect the skin and mucous membranes. The concurrent occurrence of a mucocele and a PG lesion has rarely been reported in the medical literature. This case study reports such a finding in a 16-year-old patient who presented to our department.
    Preview · Article · Sep 2011 · Annals of Dermatology
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    ABSTRACT: There has been little research on extramammary Paget's disease (EMPD) conducted in Asia. The aim of this multicenter study was to investigate the clinicopathological features, biological behavior, and treatment of EMPD in 194 Korean patients over a five-year period. As expected, this disease exhibited a male dominance (3.9:1) pattern. To distinguish the true association of malignancy with EMPD from coincidental occurrence of malignancy, we modified Chanda's guidelines. This analysis determined that there was an accompanying malignancy in 26 patients (14.4%), which included stomach (six cases), rectum (three cases), and colon (three cases) malignancies. With regard to treatment, 112 patients (58%) underwent conventional excisions, and 22 (11.4%) had Mohs surgery. Follow-up data for periods of 3-180 months were available for 147 patients; these data indicated that 42 patients (28.6%) experienced local recurrences. Patients who underwent Mohs micrographic surgery experienced a lower rate of recurrence (12.5%) than patients who underwent conventional excision (33.3%). In summary, this Korean population-based study demonstrated that the clinical features of EMPD, such as gender predominance, are consistent with reports from other Asian population-based studies. However, this study additionally demonstrated that the rate of association with malignancy in the Korean population (14.4%) was higher than that observed in other Asian studies.
    Full-text · Article · May 2011 · International journal of dermatology
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    ABSTRACT: Various therapeutic approaches have been suggested for preventing or reducing the adverse effects of topical glucocorticoids, including skin barrier impairment. Previously, we have shown that impairment of skin barrier function by the highest potency topical glucocorticoid, clobetasol 17-propinate (CP), can be partially prevented by co-application of a physiological lipid mixture containing pseudoceramide, free fatty acids, and cholesterol (multi-lamellar emulsion [MLE]). Skin atrophic effects of CP were also partially reduced by MLE. In this study, the preventive effects of MLE on the lowest potency topical glucocorticoid, hydrocortisone (HC), were investigated using animal models. Anti-inflammatory activity of topical HC was evaluated using a 12-O-tetradecanoylphobol-13-acetate-induced skin edema model. Topical steroid induced adverse effects were evaluated using hairless mouse. The results showed that the anti-inflammatory activity was not altered by co-application of either MLE or hydrobase. However, co-application of MLE and 1.0% HC showed less impairment in the epidermal permeability barrier function, skin hydration, and skin surface pH compared with hydrobase. Stratum corneum integrity, evaluated by measuring trans-epidermal water loss after repeated tape stripping, showed less damage with MLE co-application. Long-term application of topical HC induced skin atrophy, measured by a reduction in skinfold and epidermal thickness and in the number of epidermal proliferating cell nucleus antigen (PCNA)-positive keratinocytes. Co-application of MLE did not affect the skinfold or epidermal thickness, but the number of PCNA-positive keratinocytes was less decreased with MLE use. These results suggest that co-application of MLE is effective in reducing the local adverse effects of low-potency topical glucocorticoids and supports the therapeutic efficacy of physiological lipid mixtures on skin barrier function.
    Full-text · Article · Apr 2011 · Allergy, asthma & immunology research

Publication Stats

1k Citations
235.09 Total Impact Points

Institutions

  • 1991-2015
    • Yonsei University Hospital
      • Department of Internal Medicine
      Sŏul, Seoul, South Korea
    • Yonsei University
      • • Department of Dermatology
      • • Department of Biochemistry
      • • College of Medicine
      Sŏul, Seoul, South Korea
  • 2008
    • University of Ulsan
      Urusan, Ulsan, South Korea