The Low-Fluence Q-Switched Nd:YAG Laser Treatment for Melasma: A Systematic Review.

Melasma is a common pigmentary disorder with a complex pathogenesis, of which the treatment is challenging. Conventional treatment often leads to inconsistent results with unexpected pigmentary side effects and high recurrence rates. Recently, the low-fluence Q-switched Nd:YAG laser (LFQSNY) has been widely used for treating melasma, especially in Asia. We reviewed literatures on the LFQSNY treatment of melasma published between 2009 and May 2022 to evaluate the efficacy and adverse events, including its combination therapy. A systematic PubMed search was conducted and a total of 42 articles were included in this study. It was hard to summarize the heterogenous studies, but LFQSNY appeared to be a generally effective and safe treatment for melasma considering the results of previous conventional therapies. However, mottled hypopigmentation has been occasionally reported to develop and persist as an adverse event of LFQSNY, which may be associated with the high accumulated laser energy. When used aggressively, even LFQSNY can induce hyperpigmentation via unwanted inflammation, especially in darker skin. Although few studies have reported considerable recurrence rates three months after treatment, unfortunately, there is a lack of the long-term follow-up results of LFQSNY in melasma. To enhance the effectiveness and reduce the adverse events, LFQSNY has been used in combination with other treatment modalities in melasma, including topical bleaching agents, oral tranexamic acid, chemical peeling, or diverse energy-based devices, which generally reduced side effects with or without significant superior efficacy compared to LFQSNY alone.

Vitiligo and overt thyroid diseases: A nationwide population-based study in Korea.

BACKGROUND: Associations between vitiligo and thyroid diseases have been reported repeatedly. OBJECTIVE: We investigated the associations between vitiligo and overt autoimmune thyroid diseases and thyroid cancer using the Korean National Health Insurance claims database. METHODS: We defined patients with vitiligo as those whose records showed ≥4 physician contacts between 2009 and 2013 in which vitiligo was the principal diagnosis. We also established an age- and sex-matched control group without vitiligo (2 per 1 vitiligo patient). The outcomes of interest were concurrent Graves disease and Hashimoto thyroiditis (the patients were taking relevant thyroid medications) and thyroid cancer. RESULTS: The study enrolled 73,336 vitiligo patients and 146,672 controls. Patients with vitiligo were at increased risks of Graves disease (odds ratio [OR] 2.610 [95% confidence interval {CI} 2.319-02.938]), Hashimoto thyroiditis (OR 1.609 [95% CI 1.437-1.802]), and thyroid cancer (OR 1.127 [95% CI 1.022-1.242]), compared with the controls. The associations were consistently stronger in males and younger patients. LIMITATIONS: Individual clinical information was not available, and the homogeneous population may limit the generalizability of the results. CONCLUSION: Vitiligo was significantly associated with overt autoimmune thyroid diseases and overt thyroid cancer.

Subungual Posttraumatic Ectopic Nail.

Ectopic nail is defined as the malformation of nail tissue in a location other than the usual nail unit. We present a 12-year-old boy with a single dystrophic thumb nail after an injury. The nail was observed under the original nail and it is linked to the original nail plate by longitudinal bridge formation with parallel growth. According to these clinical findings, the diagnosis of subungual posttraumatic ectopic nail was made.

A Rare Case of Atypical Myxoid Cellular Neurothekeoma in a 6-Year-Old Girl.

Neurothekeoma (nerve sheath myxoma)is a benign tumor of probable nerve sheath origin. The atypical cellular variant of this tumor, showing a peculiar histologic pattern, has been very rarely reported in the literature. The atypical variant of cellular neurothekeoma is characterized by features such as large size, deep penetration extending into skeletal muscle and/or subcutaneous fat, diffuse infiltration borders, vascular invasion, high mitotic rate and marked cytologic pleomorphism. We describe a rare form of atypical myxoid cellular neurothekeoma in a 6-year-old girl.

A clinicopathologic study of thirty cases of acquired perforating dermatosis in Korea.

BACKGROUND: Acquired perforating dermatosis (APD) is histopathologically characterized by transepidermal elimination of materials from the upper dermis. APD can be divided into four diseases: Kyrle's disease, perforating folliculitis, elastosis perforans serpiginosa, and reactive perforating collagenosis. APD is usually associated with systemic diseases, especially diabetes mellitus or chronic renal failure. So far, there have only been a few Korean studies of APD, which have a limited number of patients. OBJECTIVE: The aim of this study is to evaluate the clinical and histopathologic characteristics of 30 cases of APD and to examine the association with systemic diseases. METHODS: We retrospectively reviewed the medical records and biopsy specimens of 30 patients who were diagnosed with APD. RESULTS: The mean age was 55.5 years, and the average duration of the lesion was 7.8 months. The lower extremities (73.3%) were the most frequently occurring sites of the lesion. Twenty-five patients (83.3%) had pruritus, and Koebner's phenomenon was present in 11 patients. Patients of 63.3% had at least one systemic disease. Diabetes mellitus (n=17, 56.7%) and chronic renal failure (n=10, 33.3%) were the most commonly associated conditions. Most patients received topical steroids (93.3%) and antihistamines (80.0%). The most common histopathologic type was reactive perforating collagenosis (n=23, 73.3%). CONCLUSION: In this study, most patients had a systemic association to the diseases. Therefore, we suggest that further evaluation is necessary for patients who present with APD. This includes reviewing patient's comprehensive past medical history, clinical exam, and additional diagnostic testing to check for the possibility of associated systemic diseases.

Hybrid cysts: a clinicopathological study of seven cases.

Hybrid cysts develop from more than two components of the pilosebaceous unit. The pathogenesis of this unusual disease has not yet been elucidated. The aim of this study was to assess the clinical and histopathological features of hybrid cysts. Histological sections of seven cases indexed as hybrid cysts were reviewed from 1996-2009 at the Department of Dermatology, Eulji Medical Center, Seoul, Korea. Hospital charts and slides were retrospectively evaluated. All cases had a combination of an epidermal cyst and a pilomatricoma with sharp transitional zones. The epidermal cyst lining was composed of thickened stratified squamous epithelium with a granular layer. Basophilic cells, shadow cells and the contents of the pilomatricoma were present in all lesions. There were no differences in the clinical features between patients with hybrid cysts and others with single cystic lesions. There were five women and two men, ranging in age from 11 to 50 years (mean 27 years). The most common sites were the upper extremities. None of the patients had any sign of Gardner's syndrome. Hybrid cysts are an interesting pathological phenomenon. Further study is needed to analyze hybrid cysts to improve our understanding of their pathogenesis and development from tumours of the pilosebaceous unit.

Squamous Cell Carcinoma Developing within Lesions of Disseminated Superficial Actinic Porokeratosis.

Disseminated superficial actinic porokeratosis (DSAP) consists of multiple annular, hyperkeratotic lesions that have a bilateral distribution on sun-exposed areas, particularly the extremities. DSAPs have a wider distribution than porokeratosis of Mibelli and usually develop during the 3rd or 4th decade of life. Squamous cell carcinoma that arises in the classical type of porokeratosis of Mibelli is well-documented, but there are only a few reports of squamous cell carcinoma in DSAP. Here, we describe a 62-year-old man with DSAP who developed squamous cell carcinoma on his right forearm.

A Case of Tubular Apocrine Adenoma with Syringocystadenoma Papilliferum that Developed in a Nevus Sebaceus.

Tubular apocrine adenoma (TAA) is a very rare sweat gland tumor. TAA and syringocystadenoma papilliferum (SCAP) rarely develop together in a nevus sebaceus (NS). Herein, we report on a 40-year-old Korean woman with TAA associated with SCAP that developed in a NS located on the scalp.

A nodular syphilid presenting as a pseudolymphoma: mimicking a cutaneous marginal zone B-cell lymphoma.

Syphilis has been referred to as the great imitator, the great mimic, and the great masquerader. It often presents with clinical and histological findings similar to many other dermatological conditions. We report a patient presenting with nodular plaques, a rare form of secondary syphilis. The histological features revealed a pseudolymphoma mimicking a cutaneous marginal zone B-cell lymphoma. Syphilis should be considered in the differential diagnosis of a cutaneous lymphoreticular process.