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Dermatology Online Journal is an open-access, refereed publication intended to meet reference and education needs of the international dermatology community since 1995. Dermatology Online Journal is supported by the Department of Dermatology UC Davis, and by the Northern California Veterans Administration.

Volume 25, Issue 4, 2019

Review

Extramammary Paget disease

In 1874, Sir James Paget first described Paget disease of the nipple, also known as mammary Paget disease. In 1889, extramammary Paget disease (EMPD) of the scrotum and penis was identified. Although mammary and extramammary Paget disease are both characterized by epidermal Paget cells and share a similar clinical presentation, their uniqueness lies in anatomical location and histogenesis. EMPD presents as an erythematous plaque on apocrine gland bearing areas (i.e. vulva, perineum, perianal region, scrotum, and penis) in older men and women. It can be a focal, multifocal, or an ectopic process. Immunohistochemical staining allows for differentiation between primary and secondary EMPD in addition to the many other disease entities that clinically resemble this malignancy. When diagnosing a patient with EMPD, a full history and physical should be performed given the possibility of an underlying malignancy. Surgical excision currently is first line therapy and the prognosis is often favorable. Recent advances within the field have examined the expression of chemokine receptors within tumors, which may be applicable in determining prognosis. This review addresses the history, epidemiology, pathogenesis, clinical presentation, histopathology, differential diagnosis, diagnosis, management, and new observations with respect to extramammary Paget disease.

Commentary

Healthcare and dermatology on WeChat

WeChat is a closed social networking platform that allows users to connect privately, providing instant text, photo sharing, voice, and video calls. It is now the most popular mobile chat app in China. The widespread use and ease of establishing technology made WeChat an ideal platform for healthcare, in which it has many uses that include scheduling, follow up, and post-procedure monitoring. In addition, one may make payments and handle prescriptions via e-pharmacy. Dermatologists are often looking for a secure and easy way to use mobile applications to share clinical images and to obtain photographs from patients. We aim to provide an overview of WeChat and its current applications for healthcare and dermatology.

Case Report

Oral lichen sclerosus: a rare case and update

Lichen sclerosus (LS) is a chronic inflammatory mucocutaneous disease that often affects the anogenital area; oral mucosal lesions are extremely rare. A 52-year-old woman presented for evaluation of an 8-year history of a persistent whitish plaque in the buccal mucosa. Intraoral examination revealed multiple elevated whitish plaques diffusely distributed in the buccal mucosa associated with an area of tissue atrophy. Although both leukoplakia and lichen planus were considered, incisional biopsy and later, full excision confirmed the histopathological diagnosis of oral LS. After 6 months of follow-up, there are no clinical signs of relapse. This case highlights the importance of clinical and histopathological findings for the correct diagnosis and treatment of oral LS.

Case Presentation

Incisional biopsy critical in obtaining definitive diagnosis in a clinically challenging case

Tissue-sparing biopsy techniques are frequently used in clinical practice but can result in misdiagnosis of large, clinically challenging lesions. We present a case of a 70-year-old man with hidradenocarcinoma of the left chin, a diagnosis that was delayed owing to repeated superficial biopsies that were negative for disease. Diagnosis was ultimately obtained via an incisional biopsy. We discuss the clinical features of hidradenocarcinoma and why this diagnosis can be easily missed with superficial biopsies. It is important that dermatologists consider incisional biopsies in the workup of clinically challenging lesions for which malignancy is considered.

Darier disease with disseminated herpes simplex virus type 2 infection

Darier disease (DD), also known as keratosis follicularis or Darier-White disease, is a rare autosomal dominant genodermatosis that presents as hyperkeratotic, warty papules affecting the seborrheic and intertriginous areas. Patients with DD are at risk of secondary infections including the rare complication of Kaposi varicelliform eruption (KVE), a widespread viral infection most commonly caused by herpes simplex virus (HSV). Darier disease with secondary KVE can lead to widespread systemic infection and death. This case report discusses an individual with DD who subsequently developed KVE due to disseminated HSV type 2 infection.

Multiple acantholytic dyskeratotic acanthomas in a liver-transplant recipient

Acantholytic dyskeratotic acanthoma is a rare variant of epidermal acanthoma characterized pathologically by the presence of acantholysis and dyskeratosis. Few cases have been reported until now, one of them in a heart-transplant patient. We present here a new case of this rare lesion that developed in a liver-transplant patient and review the salient features of this uncommon condition.

Late-onset amyloidosis cutis dyschromica: an unusual case

Amyloidosis cutis dyschromica (ACD) is a rare form of primary cutaneous amyloidosis. ACD, first described by Morishima in 1970 is characterized by (i) macular, speckled, reticular hyperpigmentation with hypopigmented spots distributed extensively over the body; (ii) little or no pruritus; (iii) prepubertal onset; and (iv) focal subepidermal amyloid deposition. A 49-year-old woman presented with a 20-year history of progressive, asymptomatic, generalized mottled hyper- and hypopigmented macules all over the body. Histopathological examination of a punch biopsy specimen showed deposition of homogeneous, eosinophilic material in the papillary dermis. This amorphous, eosinophilic material was stained metachromatically with crystal violet stain and found to be compatible with amyloid. Based on the clinical and histopathological findings, the patient was diagnosed as having ACD. Amyloidosis cutis dyschromica must be considered in the differential diagnosis of patients with diffuse dyschromatosis including both hyperpigmented and hypopigmented lesions and histopathological confirmation is necessary in order to reach a correct diagnosis.

Endogenous ochronosis: when clinical suspicion prevails over histopathology

Endogenous ochronosis (EO) or alkaptonuria is an inherited autosomal recessive disease caused by the insufficiency of the enzyme homogentisic acid dioxygenase. This disturbance causes an accumulation and increased renal excretion of homogentisic acid (AHG), which manifests as dark urine when it oxidizes on contact with air. Other clinical manifestations of OE are the result of the deposit of AHG in the form of ochronotic pigment at the level of collagen in the skin and cartilage, where it causes blue-gray cutaneous hyperpigmentation, degenerative arthropathy, valvular disease, and other multisystem effects. Despite the progressive and irreversible nature of OE and the lack of a curative treatment, the life expectancy is preserved. We report a new case of EO with cutaneous and joint involvement, in which a high clinical suspicion, confirmed by elevated AHG in urine was the key in the diagnosis.

Molluscum contagiosum with dermoscopic features in an unusual areola and nipple location

Molluscum contagiosum is a common, contagious viral skin disease that often affects children and adolescents. Involvement of the areola and nipple are rarely reported. Herein we report two young women with molluscum contagiosum on the areola-nipple complex and we discuss the dermoscopic features of the lesions at this unusual site.

Photo Vignette

Morphea secondary to interferon beta1b injection: a case and review of the literature

Interferon beta (IFNβ) is a drug used successfully in the treatment of multiple sclerosis (MS). Although IFNβ is a safe and well-tolerated drug, dermatological side effects are common. The most common dermatological adverse effect is a local reaction at the injection site. It may also cause inflammatory and immune-mediated dermatological side effects. However, morphea induced by IFNβ1b injection is very rare

Allergic contact dermatitis related to homemade slime: a case and review of the literature

Slime has become extremely popular as a children's toy in recent years and is typically made with various household substances. Although reports of slime causing skin irritation are not uncommon, case reports of slime-induced allergic contact dermatitis have only recently surfaced. We present a case of a child with hand dermatitis, history of exposure to slime, and positive allergen patch testing to two ingredients found in slime. The case underscores the need for clinicians to be aware of slime as a possible cause of allergic contact dermatitis in children. Given the trend of newly-reported cases, we briefly review the current literature to date.

Exogenous ochronosis: the failure of depigmenting creams

Exogenous ochronosis (EO) is an entity that manifests as black-bluish or grayish-brown cutaneous hyperpigmentation, which is a consequence of the deposition of ochronotic pigment with characteristic banana-like morphology between the collagen fibers of the dermis. Both the clinical presentation and histopathology appearance are superimposable with endogenous ochronosis or alcaptonuria, a hereditary disease in which ochronotic pigment deposition occurs at a multisystemic level. The most frequent cause of EO is the use of facial depigmenting creams containing hydroquinone, a common practice among women with high phototypes. We present a woman who developed EO on the face, upper chest, and back after prolonged use of a depigmenting cream containing hydroquinone.

Letter

Melanoma patient notification and treatment timelines

Melanoma is an extremely aggressive cancer for which the American Academy of Dermatology currently does not have formal recommendations outlining a timeline from biopsy to definitive treatment. Our dermatology department investigated our treatment timeline for melanoma. Using the database from our electronic medical record, Epic, we evaluated patients over a one-year period; in total we identified 109 melanomas. We evaluated patient demographics, tumor characteristics, and timelines regarding diagnosis and treatments. There was a statistically significant difference in patient notification of diagnosis and treatment times between stage 1 and stages 2-4 combined (based on the American Joint Committee on Cancer staging system). We found that 84% of melanomas were treated within 4 weeks of diagnosis and 96% within 6 weeks. The lower the stage, the earlier the melanoma was definitively treated; higher stage melanomas had a longer delay to definitive treatment. Herein, we have presented our single institutional experience of the melanoma timeline from diagnosis to definitive treatment and have identified factors that impact timely definitive treatment.

Paradoxical reversed plantar involvement during ixekizumab therapy for psoriasis

Palmoplantar psoriasis is a particularly challenging variant of psoriasis. Psoriasis at this location has a significant impact on health-related quality of life and is often recalcitrant. However, difficult cases may respond to biologic therapies. Paradoxical reactions during treatment with biological agents have been described, mostly during anti-tumor necrosis factor therapy. These typically present as a change in morphology or distribution of lesions. We present a patient with palmoplantar psoriasis treated with ixekizumab who achieved a favorable response that was coupled with a rare paradoxical reaction, reversed plantar involvement. The reason for this phenomenon and its clinical course are uncertain, but these new lesions are proving recalcitrant to complementary therapies. Provided the increasingly widespread use of biologic therapies, the incidence and diversity of paradoxical reactions are expected to increase.

Metastatic squamous cell carcinoma arising in the setting of folliculitis decalvans

Squamous cell carcinomas (SCCs) often arise secondary to UV-induced DNA damage resulting in genetic mutations, but can also occur in the setting of prolonged inflammation. Folliculitis decalvans (FD) is a rare cicatricial alopecia with a complex, multifactorial pathogenesis that results in chronic inflammation and scarring. We present a patient with severe, chronic FD who developed metastatic squamous cell carcinoma of the scalp.

Corrigendum

Corrigendum: A novel ultraviolet B home phototherapy system: Efficacy, tolerability, adherence, and satisfaction

The original article was published on February 15, 2019 and corrected on April 15, 2019.

The third pair of panes of Figure 2 were reversed, such that the pane previously depicted on the left was after phototherapy. The corrected sequence is now before phototherapy, on the left, and after, on the right. This change appears in the revised online PDF copy of this article.