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Open Access Publications from the University of California

Dermatology Online Journal

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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 30, Issue 1, 2024


Clinical features of atypical presentations of mucocutaneous herpes simplex virus infection observed in immunosuppressed individuals. Part I: herpetic geometric glossitis

Herpetic geometric glossitis is a unique morphologic variant of HSV (herpes simplex virus) type 1 infection on the dorsum of the tongue that presents as an extremely painful linear central lingual fissure with a branched pattern. in the center of the tongue; there is a branched pattern of fissures that extend bilaterally from the central linear fissure. Herpetic geometric glossitis has been reported in 11 patients; 8 of these individuals were immunocompromised. Medical conditions and immunosuppressive medication treatment (7 patients) or only medical disorders (3 patients) or neither (1 patient) were present. HSV type 1 infection was diagnosed by viral culture in (7 patients), Tzanck preparation (2 patients) or clinically (2 patients). Mucocutaneous HSV infection at non-lingual locations--including the lips, labial mucosa, face and chest--were observed in 5 patients. All patients' symptoms and lesions responded to treatment with oral antiviral therapy: acyclovir (9 patients), famciclovir (1 patient) or valacyclovir (1 patient). The lingual pain and dorsal tongue fissures completely resolved completely within two to 14 days. In summary, herpetic geometric glossitis is a unique HSV type 1 infection, usually in immunocompromised patients, that occurs on the dorsal tongue and responds completely after treatment with orally administered antiviral therapy.

Clinical features of atypical presentations of mucocutaneous herpes simplex virus infection observed in immunosuppressed individuals. Part II: the knife-cut sign

The knife-cut sign is a distinctive manifestation of herpes simplex virus (HSV) type 1 or HSV type 2 infection that has been described in at least 10 immunocompromised patients. It appears as an extremely painful linear erosion or fissure in an intertriginous area such as the body folds beneath the breast, or within the abdomen, or in the inguinal region. Also, concurrent HSV infection at other mucocutaneous sites, or viscera, or both have been observed. The patients had medical conditions (at least 9 patients) and/or immunosuppressive drug therapy (6 patients). The diagnosis of HSV infection was confirmed by viral culture (8 patients), biopsy (4 patients), direct fluorescence antibody testing (3 patients), immunohistochemistry staining (2 patients), polymerase chain reaction (2 patients), or Western blot serologic assay (1 patient). Knife-cut sign-associated HSV infection is potentially fatal; three patients died. However, clinical improvement or complete healing occurred in the patients who received oral valacyclovir (1 patient), or intravenous acyclovir (2 patients), or intravenous acyclovir followed by foscarnet (1 patient). In summary, HSV infection associated with a positive the knife-cut sign is a potentially fatal variant of HSV infection that occurs in the intertriginous areas of immunocompromised patients and usually requires intravenous antiviral therapy.


Retronychia: the importance of proper footwear

Retronychia is commonly underdiagnosed and exhibits classic features of proximal nail fold elevation and nail plate layering. Herein we summarize the literature and discuss cause, diagnosis, and treatment of this condition.

Case Report

A confounding clinically aggressive case of necrotizing granulomatous and suppurative dermatitis

Superficial granulomatous pyoderma gangrenosum is a rare, superficial, vegetating form of pyoderma gangrenosum that tends to occur as a single lesion, most commonly on the trunk. Herein, we report a clinically confounding case of disseminated superficial granulomatous pyoderma gangrenosum in a patient with a 5-year history of painful and chronic ulcerations of the bilateral upper extremities and face in a sun exposed distribution. This was a diagnostically challenging case due to the treatment-refractory nature of our patient's skin lesions and the atypical clinical and histologic presentations encountered. We review our clinical decision process and acknowledge other entities that were considered during the clinical course of this case. Additionally, we discuss the lack of responsiveness to various treatment options with eventual successful clearance of this patient's active skin disease with initiation of adalimumab.

Successful secukinumab treatment of generalized pustular psoriasis

Generalized pustular psoriasis is a rare variant of psoriasis. Evidence recommending generalized pustular psoriasis treatment with secukinumab is limited. This report aims to evaluate the use of secukinumab in two patients with generalized pustular psoriasis. The standard treatment regimen for secukinumab was as follows: 300mg subcutaneously once weekly in weeks 0-4, followed by 300mg every four weeks. The efficacy was evaluated by analyzing the psoriasis area and severity index (PASI) and dermatology life quality index (DLQI). One patient had generalized pustular psoriasis, which had developed from palmoplantar pustulosis over 12 years. The second patient was an adolescent with recurrent generalized pustular psoriasis. The first patient achieved PASI-75 response by week 3 and both PASI-90 and a DLQI score of 0 were observed by week 8. The second patient achieved PASI-75 response by week 4 and complete clinical resolution, except for nail changes, and a DLQI of 0 by week 8, without any adverse events.

Basal cell carcinoma in situ of the skin revisited: case reports of the superficial type and fibroepithelioma type of this in situ cutaneous neoplasm

Cutaneous basal cell carcinoma in situ is a recently proposed subtype of this skin cancer. It is characterized by either restriction of the tumor cells within the epidermis or the presence of tumor cells contiguous with the overlying epidermis that extend into the underlying dermis, or both. Importantly, cancer invasion-demonstrated by non-contiguous aggregates of basaloid tumor cells in the dermis-is not a feature of in situ basal cell carcinoma of the skin. A 63-year-old woman with cutaneous basal cell carcinoma in situ-superficial type that presented as an erythematous scaly plaque on her abdomen and a 61-year-old man with a cutaneous basal cell carcinoma in situ-fibroepithelioma type that presented as a flesh-colored smooth exophytic nodule on his back are reported. The characteristics of in situ basal cell carcinoma of the skin in these individuals are summarized. In conclusion, similar to other cutaneous malignant neoplasms-such as squamous cell carcinoma, malignant melanoma, and Merkel cell carcinoma-basal cell carcinoma of the skin can also present as an in situ cancer.

Infliximab-induced amicrobial pustulosis of the folds in a patient with Crohn disease

Tumor necrosis factor (TNF) inhibitors may paradoxically induce pustular eruptions, most of which are classified as pustular psoriasis. Amicrobial pustulosis of the folds (APF) is a much rarer entity that was recently recognized to occur in the setting of chronic anti-TNF therapy and inflammatory bowel disease, with 12 existing cases in the literature. Amicrobial pustulosis of the folds is a neutrophilic dermatosis characterized by aseptic pustules involving the major and minor skin folds, genital regions, and scalp. Herein, we report an additional case of paradoxical APF induced by chronic infliximab therapy in a patient with Crohn disease.

Patients with a new-onset cutaneous sebaceous neoplasm following immunosuppression should be evaluated for Muir-Torre syndrome with germline mismatch repair gene mutation analysis: case reports

Patients with Muir-Torre syndrome may have a systemic malignancy and a sebaceous neoplasm such as an adenoma, epithelioma, and/or carcinoma. The syndrome usually results from a germline mutation in one or more mismatch repair genes. Iatrogenic or acquired immunosuppression can promote the appearance of sebaceous tumors, either as an isolated event or as a feature of Muir-Torre syndrome and may unmask individuals genetically predisposed to the syndrome. Two iatrogenically immunosuppressed men with Muir-Torre syndrome features are described. Similar to these immunocompromised men, Muir-Torre syndrome-associated sebaceous neoplasms have occurred in solid organ transplant recipients, human immunodeficiency virus-infected individuals, and patients with chronic diseases who are treated with immunosuppressive agents. Muir-Torre syndrome-associated sebaceous neoplasms occur more frequently and earlier in kidney recipients, who are receiving more post-transplant immunosuppressive agents, than in liver recipients. The development of sebaceous neoplasms is decreased by replacing cyclosporine or tacrolimus with sirolimus or everolimus. Specific anti-cancer vaccines or checkpoint blockade immunotherapy may merit exploration for immune-interception of Muir-Torre syndrome-associated sebaceous neoplasms and syndrome-related visceral cancers. We suggest germline testing for genomic aberrations of mismatch repair genes should routinely be performed in all patients-both immunocompetent and immunosuppressed-who develop a Muir-Torre syndrome-associated sebaceous neoplasm.

Case Presentation

Spindle cell lipoma: a rare case report on the hallux

Spindle cell lipomas are a rare type of lipoma usually presenting in middle-aged to older men, often located on the posterior neck or shoulder; presentation on the foot is exceptionally uncommon. We report a 24-year-old man with spindle cell lipomas on the hallux of his left foot. He experienced an uneventful recovery after excision of the mass. We discuss clinical, radiologic, and histopathologic features of spindle cell lipomas and we review the differential diagnosis at this anatomic site.

Multiple juvenile xanthogranuloma

Juvenile xanthogranuloma is the most frequent form of non-Langerhans cell histiocytosis in children. Clinically, it presents as well defined, yellowish papules that are typically located on the head, neck, upper trunk, and proximal region of the extremities. Although solitary lesions are the most common presentation, few cases of multiple juvenile xanthogranuloma have been described, more frequently associated with extracutaneous involvement. We report a 2-month-old girl with 22 cutaneous papules, clinically and histologically compatible with juvenile xanthogranulomas. Screening of visceral involvement was performed with no evidence of systemic disease. Identifying high-risk factors of systemic disease in patients with multiple juvenile xanthogranuloma is essential to perform an appropriate management of this entity.

Fast and safe clinical response to sonidegib in a 98-year old woman affected by locally advanced basal cell carcinoma

A 98-year-old woman presented with histologically confirmed locally advanced basal cell carcinoma of the face. A multidisciplinary approach excluded surgery because of the site near sensitive organs, extension, age, and comorbidities. Patient and caregivers declined radiotherapy considering the necessity of multiple hospital appointments. The patient was then placed on therapy with sonidegib, an oral inhibitor of the Hedgehog signaling pathway. There was a very rapid clinical response after only 28 days of treatment. The basal cell carcinoma improved progressively, with no adverse events reported. This case illustrates the efficacy and safety of this treatment in an advanced age patient. This treatment had a remarkably positive impact on quality of life, including that of the caregivers.

Verrucous carcinoma presenting as recalcitrant verruca plantaris

Verrucous carcinoma (VC) is a rare, low-grade variant of well-differentiated squamous cell carcinoma. Plantar verrucous carcinoma presents as a slow-growing, exophytic, verrucous plaque on weight bearing areas of the foot. Verrucous carcinomas have low metastatic potential, but are high risk for local invasion. We describe a patient with a 20-year history of a slowly growing, ulcerated, verrucous plaque on the sole of the left foot that was erroneously treated for years as verruca plantaris and was eventually diagnosed as invasive verrucous carcinoma. Verrucous carcinomas are a diagnostic challenge due to clinical and histopathologic mimicry of benign lesions. Mohs micrographic surgery should be employed to allow the ability to intraoperatively assess tumor margins while excising the minimal amount of necessary tissue. It is important for clinicians to recognize the characteristics and accurately diagnose verrucous carcinomas. Delays in treatment may require more extensive dissection or amputation.

Stevens-Johnson syndrome/toxic epidermal necrolysis associated with natural thyroid medication

Steven-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) is a rare immunologic hypersensitivity reaction to stimuli that presents as widespread eruption with mucocutaneous detachment and involvement of other organs. Multiple causes have been noted in literature, including numerous medications. In this report, we present a 52-year-old woman who arrived at the emergency department with a complaint of rash, malaise, and pruritus. She subsequently developed diffuse cutaneous and mucosal detachment. Work-up supported a diagnosis of SJS/TEN secondary to her thyroid replacement therapy, derived from desiccated pig thyroid glands. The patient's natural thyroid medication was discontinued and she responded well to appropriate treatment. This case is unique in that thyroid replacement therapy is not a commonly reported trigger of SJS/TEN. Providers should be aware of the potential for natural thyroid and other animal-derived natural medications to cause adverse reactions such as SJS/TEN.

Photo Vignette

Congenital liquified subcutaneous fat necrosis in a newborn: an unusual case

Subcutaneous fat necrosis of the newborn is a self-limited disorder of the panniculus that arises in the first six weeks of life. Some differential diagnoses may be difficult such as bacterial cellulitis or erysipelas. The prognosis is usually favorable but there are serious complications for which the patient must be regularly monitored, especially hypercalcemia. We report a case of a full-term newborn with a liquidated area of subcutaneous fat necrosis. A surgical incision was performed because of the discomfort and the lack of regression. Hypercalcemia and nephrocalcinosis appeared afterward. A set of clinical, biological, and histological arguments allows the diagnosis of subcutaneous fat necrosis. Follow-up to early detection and to manage such complications is necessary.

Milia en plaque on the shoulder as an early manifestations of mycosis fungoides

Milia en plaque (MEP) is an uncommon skin condition identified as retroauricular confluent milium by Boulzer and Fouqet in 1903 [1]. It can be mistaken for other dermatoses like Favre-Racouchot nodular elastosis, steatocystoma multiplex, and nevus comedonicus. Milia en plaque can either be primary or secondary and is typically benign, often triggered by dermatological procedures like cryotherapy, as reported in this journal. In some cases, MEP can arise as a secondary manifestation of other diseases, including folliculotropic mycosis fungoides (FMF). Despite this association, there are few documented cases in the literature. Herein, we present a patient in whom MEP served as the initial clinical presentation of FMF; the treatment involved oral retinoids and phototherapy. Furthermore, we highlight distinctive features of both conditions. It is important to emphasize that early diagnosis and treatment of FMF are vital for the patient's quality of life. The presence of MEP can serve as a valuable indicator for identifying it.

Osteonecrosis of the jaw after radiation followed by bevacizumab

Osteonecrosis of the jaw is a recognized complication associated with bevacizumab. Here, we present a patient with squamous cell carcinoma of the tonsil who experienced minimal skin fibrosis following intensity-modulated radiation therapy. Subsequently, the patient developed rectal adenocarcinoma and encountered osteonecrosis of the jaw after receiving two cycles of bevacizumab. Close monitoring, accompanied by thorough examination to detect early signs of osteonecrosis of the jaw, should be considered for patients who have undergone radiation therapy in the head and neck region and are receiving bevacizumab or other medications known to be associated with osteonecrosis of the jaw.