Introduction
Dowling-Degos disease (DDD) was first described as a benign form of acanthosis nigricans by Dowling and Freudenthal in 1938, then referred to as“dermatose reticulée des plis”by Degos and Ossipowski in 1954, and was first named DDD by Wilson-Jones and Grice in 1978[1]. The disease has been reported worldwide and affects both genders equally. As an autosomal dominant pigment disorder, it usually occurs in postpubertal individuals, and is seldom seen in children[2]. However, a Chinese newborn with DDD was reported in 2008[3]. In this review, we summarize features of DDD, emphasizing advances in genetics research and looking to the future for further understanding of its etiology and the development of therapeutic methods.

Introduction
Keloids, a type of skin lesion that presents as pathologically excessive dermal fibrosis and aberrant wound healing, are caused by cell proliferation and hyaline degeneration of connective tissues. The specific pathogenesis of keloids is still unknown[1- 2]. There are multiple therapeutic strategies for keloids, including surgery, cryotherapy, laser or light-based therapy, and intralesional corticosteroid injection. However, none of these is optimal. Surgical excision combined with adjuvant radiation is considered to be a safer and more efficacious method[3]. From publicly available data, the recurrence rate of keloids after simple surgical excision amounts to 45% - 100%[4]. Based on published reports, postoperative adiotherapy results in a control rate of 67% - 81% , and the recurrence rate decreases to 24.5% - 35%[4-12]. This article reviews papers related to postoperative radiotherapy treatment for keloids, and also discusses radiation types, parameters, safety and effectiveness.

Nevus sebaceous (NS), also known as nevus sebaceous of Jadassohn, is a congenital sebaceous hyperplasia or organoid nevus. This benign congenital hamartoma is composed of abnormal epidermal and dermal components. The hamartomatous lesions, usually clinically present at birth, are most frequently distributed on areas with sebaceous glands, especially the scalp and face[1]. NS originates from pluripotent primordial epithelial germ tissue and occurs in approximately 0.1% of newborns.

Introduction
Giant condyloma acuminatum, which is also known as Buschke-Loewenstein tumor (BLT), is a uncommon sexually-transmitted disease affecting the genitals and characterized by a slow and locally-invasive growth pattern. It was first reported in 1925[1], and was defined as “carcinoma-like condylomata acuminate of the penis” by Loewenstein in 1938[2]. The typical clinical manifestations included exophytic, fungating masses, sometimes with a cauliflower-like morpho-logy. Therapies including surgical excision are effec-tive to the lesions of giant condyloma acuminatum, but the high recurrence rate brings troubles and pain to patients. In this report, we used electrosurgery and carbon dioxide (CO2) laser as the primary treatment followed by 5-aminolevulinic acid-photodynamic therapy (5-ALA PDT), and achieved 100% clinical efficacy on a case of giant condyloma acuminatum.

Introduction
Hyperkeratosis of nipples and areola (HNA) is a benign skin disease with unknown etiology, and is sporadic and clinically rare. It was first described by Tauber in 1923, and characterized by verrucous hyper-keratosis and dark brown pigmentation of nipples and/or areola[1]. Currently, the classification proposed by Levy-Franckel in 1938 is widely used[2], which divides HNA into three types accoding to its clinical mani-festations: TypeⅠ is characterized by the extension of epidermis nevus, involving only unilateral nipple and/or areola. TypeⅡ is mostly bilateral, involving nipples and areolae, and usually accompanied by other skin diseases, for example ichthyosis, acanthosis nigricans, Darier’s disease, chronic eczema, allergic dermatitis, and skin T cell lymphoma. TypeⅢ is congenital or nevus-shaped, and mostly occurrs among 20 to 30 years old females, with involvement of bilateral nipples and/or areolae. Herein, we reported a female patient with hyper-keratosis of bilateral giant nipples and areolae, who was successfully treated by surgery in the Hospital for Dermatology.

Introduction
Pyoderma gangrenosum (PG) is a chronic skin disease characterized by progressive lesions that present as painful suppurative ulcers and tend to recur. The pathogenesis of the disease is incompletely under-stood; however, 50% to 70% of affected persons have an associated concomitant systemic disease such as inflammatory bowel disease (IBD)[1]. Any site of the body can be affected; however, involvement of the oropharynx is rare. Here, we present a patient with disseminated PG with oropharyngeal involvement.

Introduction
Infantile hemangiomas (IHs) are the most common benign tumors of infancy[1], and the incidence ranges from 4% to 5%. They are more common in females and Caucasians, and are associated with low birth weight and prematurity of infants. Although IHs are benign and regress spontaneously[2], significant morbidity and mortality can occur during any phase, in particular during the proliferative phase of tumors. Intervention is indicated if the IHs are expected to cause morbidities.

Introduction
Subcorneal hematoma is most commonly seen on palms and soles. Its patterns seen on dermoscopy have been previously described[1-2], but dermoscopic signs
of subcorneal hematoma on other sites were few reported. Here, we present two cases of subcorneal hematoma on the extremities with characteristic findings observed by dermoscopy.

Introduction
Bullous pemphigoid (BP) is an autoimmune blistering disease that affects patients of advanced age. BP is characterized clinically by tense bullae on the extremities and trunk, histopathologically by subepi-dermal blisters with eosinophilic infiltration, and immunologically by autoantibodies to BP180 and BP230. Direct immunofluorescence of perilesional skin shows depositions of IgG and C3 in the basement membrane zone[1]. BP rarely shows prominent milia formation, which is a hallmark of epidermolysis bullosa acquisita. We herein describe a 53-year-old man with refractory BP showing numerous milia during recovery.

Histopathology
A histopathological examination of skin lesions in mild cases of erythrocyanosis only show lymphocytic infiltration in the upper dermis. In severe cases， dilation of shallow capillaries, endothelial swelling, extravasation of erythrocytes, and occasionally throm-bosis in capillaries can also be found. In this case we described here, the epidermis did not show any abnormal features. The dermis showed dilatation of capillaries and perivascular lymphocytic infiltration (Figure 1).