Cutaneous Rosai-Dorfman Disease: A Case Report

Rosai-Dorfman disease (RDD) is a rare benign non-Langerhans cell histiocytosis. The most common site of extranodal involvement is the skin. Cutaneous involvement without lymphadenopathy is extremely rare. It is often difficult to diagnose primary cutaneous RDD secondary to the non-specific nature of its clinical and histologic features. Consequently, diagnosis can be significantly delayed. To our knowledge, about 220 reports of purely cutaneous RDD are documented in the literature to date. We present an additional unique case of cutaneous RDD and emphasize the challenging nature of accurate clinical and histopathologic diagnosis.

Lumpy, bumpy guinea pigs: a retrospective study of 619 biopsy samples of externally palpable masses submitted from pet guinea pigs for histopathology

Biopsy data on externally palpable masses in pet guinea pigs were retrieved from the archives of a large commercial pathology laboratory between November 2013 and July 2021. Of the 619 samples submitted from 493 animals, 54 (8.7%) had arisen from the mammary glands and 15 (2.4%) from the thyroid glands, with the remaining 550 (88.9%) involving the skin and subcutis, muscle (n = 1), salivary glands (n = 4), lips (n = 2), ears (n = 4) and peripheral lymph nodes (n = 23). Most of the samples were neoplastic, with 99 masses classified as epithelial in origin, 347 as mesenchymal, 23 as round cell, five as melanocytic and eight as unclassified malignant neoplasms. Lipomas were the most common neoplasm diagnosed, accounting for 286 of all samples submitted.

Transdermal drug delivery in horses: An in vitro comparison of skin structure and permeation of two model drugs at various anatomical sites

BACKGROUND

Oral and parenteral drug delivery in horses can be difficult. Equine-specific transdermal drug formulations offer improved ease of treatment; development of such formulations requires a deeper understanding of the structural and chemical tissue barrier of horse skin.

HYPOTHESIS/OBJECTIVES

To compare the structural composition and barrier properties of equine skin.

ANIMALS

Six warmblood horses (two males, four females) with no skin diseases.

MATERIALS AND METHODS

Routine histological and microscopic analyses were carried out with image analysis for skin from six different anatomical locations. In vitro drug permeation was analysed using a standard Franz diffusion cell protocol coupled with reversed phase-high-performance liquid chromatography detailing flux, lag times and tissue partitioning ratios of two model drug compounds.

RESULTS

Epidermal and dermal thicknesses varied between sites. The dermal and epidermal thicknesses of the croup were 1764 ± 115 μm and 36 ± 3.6 μm, respectively, and were significantly different (p < 0.05) from the inner thigh thicknesses which were 824 ± 35 μm and 49 ± 3.6 μm. Follicular density and size also varied. The highest flux for the model hydrophilic molecule (caffeine) was for the flank (3.22 ± 0.36 μg/cm² /h), while that for the lipophilic molecule (ibuprofen) was for the inner thigh (0.12 ± 0.02 μg/cm² /h).

CONCLUSIONS AND CLINICAL RELEVANCE

Anatomical location differences in equine skin structure and small molecule permeability were demonstrated. These results can aid in the development of transdermal therapies for horses.

Legionella longbeachae wound infection: case report and review of reported Legionella wound infections

Extrapulmonary manifestations of infection with Legionella species, of which 24 may cause disease in humans, are very rare. Here, we describe a case of a 61-year-old woman with no history of immunosuppression presenting with pain and swelling of her index finger after a prick by rose thorns during gardening. Clinical examination showed fusiform swelling of the finger with mild redness, warmth, and fever. The blood sample revealed a normal white blood cell count and a slight increase in C-reactive protein. Intraoperative observation showed extensive infectious destruction of the tendon sheath, while the flexor tendons were spared. Conventional cultures were negative, while 16S rRNA PCR analysis identified Legionella longbeachae that also could be isolated on buffered charcoal yeast extract media. The patient was treated with oral levofloxacin for 13 days, and the infection healed quickly. The present case report, with a review of the literature, indicates that Legionella species wound infections may be underdiagnosed due to the requirement for specific media and diagnostic methods. It emphasizes the need for heightened awareness of these infections during history taking and clinical examination of patients presenting with cutaneous infections.

From the Cochrane Library: Interventions for Cutaneous Molluscum Contagiosum

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Cutaneous myoepithelioma with EWSR1 gene rearrangement and its differentials: A diagnostic challenge

Cutaneous myoepithelioma is a rare benign soft tissue neoplasm of myoepithelial cells involving the skin and subcutis. These tumors can be diagnostically challenging. The plasticity of myoepithelial cells leads to wide variability in the cytomorphology, immunophenotype, and genetic features of myoepithelioma. Their protean presentations may mimic malignant neoplasms. Therefore, distinction from malignancy is essential. Herein, we report a case of cutaneous myoepithelioma presenting similarly to Ewing sarcoma, with small round blue cells and an EWSR1 rearrangement. Our case highlights the important morphologic, immunohistochemical, and cytogenetic features of this benign basaloid cutaneous tumor.

Unusual Canine Cutaneous Melanoma Presenting Parietal Bone Metastasis: A Case Report

Melanocytic tumour anatomic location is considered an important prognostic indicator. The cutaneous forms are generally considered benign and may show various biological behaviours. This work reports a rare case of canine cutaneous melanoma showing parietal bone metastasis. Bone invasion in melanocytic tumours is often described in oral or visceral melanomas, but not in cutaneous forms. The patient (dog, male, mixed breed, 12 years) was initially presented for the surgical removal of a cutaneous tumour located on the skin of the carpal region of the right forelimb. Four months after, the patient returned with enlarged lymph nodes and acute respiratory failure. The patient was euthanized due to a decline in physical condition. The necropsy showed metastases in the affected forelimb, regional lymph node, splanchnic organs, parietal bone and meninges. Histopathological examination of tumour tissue samples revealed a mixture of pigmented and non-pigmented spindle and epithelioid melanocytes, while according to immunohistochemistry, the tumours showed a strong immunopositivity for VEGF and MMP-10, and a moderate positivity for MMP-2 expression. This case shows that cutaneous melanocytic tumours may show an aggressive malignant form with positive immunohistochemical reactions for multiple invasiveness factors.

Mobile Subcutaneous Calcinosis Cutis: A Case Report of a Mobile Solitary Subepidermal Calcified Nodule on a Woman's Leg and a Review of Mobile Subcutaneous Tumors

Calcinosis cutis describes the deposition of calcium in the dermis. A case of a 69-year-old woman with idiopathic calcinosis cutis that presented as a mobile subcutaneous nodule is described. The patient had an asymptomatic, firm, mobile subcutaneous nodule on her right lower leg of at least six months duration. The nodule could be easily moved from one location to another. An incisional biopsy was performed. Microscopic examination of the tissue specimen showed islands of basophilic calcium material in dense sclerotic dermal connective tissue establishing the diagnosis of calcinosis cutis. Mobile solitary calcification is an unusual presentation of idiopathic calcinosis cutis. In addition to idiopathic calcinosis cutis, benign mobile subcutaneous tumors have also been derived from adnexal structures of hair follicles and adipose tissue. Hence, not only idiopathic calcinosis cutis, but also subepidermal calcinosis in the ocular adnexa, proliferating trichilemmal cyst with focal calcification, and mobile encapsulated adipose tissue can present as a mobile subcutaneous nodule. The features of idiopathic calcinosis presenting as a mobile subcutaneous nodule as well as the characteristics of other benign mobile subcutaneous tumors are reviewed.

Congenital candidiasis in a full-term infant: A case report

Congenital systemic candidiasis is a rare disease observed in both full-term and preterm infants. It can occur with or without congenital cutaneous candidiasis (CCC) and to date, only a few cases have been reported in the literature. We report here, a case of a full-term newborn who presented with diffuse skin eruptions at birth. Blood, urine, and skin scraping cultures were positive and the aetiological agent was Candida albicans. After six weeks of anti-fungal treatment with fluconazole, the newborn was cured. Early diagnosis is crucial in preventing complications caused by candidiasis in newborns.

Primary cutaneous extraskeletal osteosarcoma: a series of 16 cases

Extraskeletal osteosarcoma (EOS) is a high grade soft tissue tumour characterised by the production of malignant osteoid, without attachment/involvement of underlying bone/periosteum. Rarely, EOS presents as a cutaneous tumour. The clinical behaviour of primary cutaneous EOS (PC-EOS) remains incompletely characterised. Herein we present the largest case series of PC-EOS reported to date. Sixteen PC-EOS cases from the archives/consultation files were retrieved (male:female 1:1; age 31-96 years, mean age 66 years). The tumours measured 1-10 cm (mean 3.2 cm) and were located on the lower extremity (7), head (6), upper extremity (2), and trunk (1). They consisted of pleomorphic, spindled-to-epithelioid cells, with fascicular, nodular, or sheet-like growth patterns and foci of malignant osteoid. Immunohistochemistry did not reveal specific lines of differentiation, and there was no evidence of other tumour types. A literature review was conducted to identify all well characterised cases of PC-EOS. A combined analysis of present and past cases was performed to determine overall trends in clinical characteristics and outcomes. The mean follow-up period was 23.9 months, during which 67.5% of patients experienced progression-free survival and 18% of patients died of disease. Rates of local recurrence and metastasis were 10% and 25%, respectively, approximately double past estimates. These data suggest that the prognosis of PC-EOS is less favourable than previously thought. The differential diagnosis includes benign entities (e.g., ossifying pyogenic granuloma) and malignant neoplasms with heterologous osteosarcomatous differentiation (e.g., carcinosarcoma, transdifferentiated melanoma). Wide excision remains the standard of care, and the role of chemotherapy and radiation remains inconclusive. Recognition of this rare entity can facilitate prompt diagnosis and appropriate treatment.

Cutaneous squamous cell carcinoma: state of the art, perspectives and unmet needs

Squamous cell carcinoma of the skin (cSCC) is one of the most common cancers of the Caucasian population and accounts for 20% of all cutaneous tumors. An S3 guideline from the German Guideline Program in Oncology has been available since 2019 and was updated in 2022. The diagnosis of cSCC is based on clinical examination. Excision and histological confirmation are required for clinically suspicious lesions to allow for prognostic assessment and correct treatment. The treatment of first choice is excision with complete histological assessment of the surgical margins. Adjuvant radiation therapy may be considered if there is a high risk of recurrence. The immune checkpoint inhibitor cemiplimab is approved and recommended as the treatment of first choice for locally advanced or metastatic cSCC in Europe. If contraindications are present, chemotherapy, EGFR inhibitors, or palliative radiation therapy may be used. Surveillance should be performed in a risk-stratified manner and includes a dermatological control supplemented by sonography examinations in high-risk patients. Much research is still needed for solid organ transplant patients, concomitant hematologic diseases, and cSCC showing primary or acquired resistance to immunotherapies. Current developments include new drug combinations, intralesional therapies alone or in combination with immune checkpoint inhibitors, and neoadjuvant approaches.

Cutaneous Perfusion Dynamics of the Lower Abdomen in Healthy Normal Weight, Overweight and Obese Women: Methods Development Using Infrared Thermography with Applications for Future Wound Management after Caesarean Section

BACKGROUND

Evidence has shown an association between obesity and an increased risk of wound infection after caesarean section. This study was designed to examine if abdominal subcutaneous adiposity impacts upon cutaneous perfusion dynamics.

METHODS

Mild cool challenge, followed by real-time video thermography, was developed to map the appearance of abdominal 'hot spots'. Correspondence of marked 'spots' with audible Doppler and colour and power Doppler ultrasound was performed.

RESULTS

60 healthy, afebrile, women (20-68 years; BMI 18.5-44 kg/m²) were recruited. Hot spot appearance consistently corresponded with audible Doppler sounds. Colour and power Doppler ultrasound revealed vessels at depths of 3-22 mm. No statistically significant interactions for BMI, abdominal circumference or environmental parameters were observed for hot spot count. The temperature of cold stimulus was significant for effects on spot count, but only for the first minute (p = 0.001). Thereafter, effects on spot numbers were not significant.

CONCLUSIONS

Cutaneous 'perforator' mapping of the abdomen (via hot spot appearance) in healthy women, as a potential and future method for risk of perfusion-dependent wound healing complications, reveals that bedside mapping of skin perfusion is feasible over a short interval. Hot spot number was not influenced by BMI or indicators of central fat distribution (abdominal circumference) indicating variability in an individual's vascular anatomy. This study provides the underpinning methodology for personalised perfusion assessment after incisional surgery which may be a more reliable indicator of potential healing complications than body habitus as is currently the norm.

"It's Like You Stuck a Pin in It:" African American/Black Patients Describe Cutaneous Toxicity From Epidermal Growth Factor Receptor Inhibitors

Background: Epidermal growth factor receptor (EGFR) inhibitors cause cutaneous toxicity in over 90% of patients. Conceivably, healthcare providers could overlook such toxicity in African American/Black patients because of a darker complexion. This qualitative study sought to learn about such cutaneous signs and symptoms and, if present, to report them in patients' own words. Methods: Any patient who self-identified as African American/Black and who had been prescribed an EGFR inhibitor was eligible. The current report focuses on patients' responses to the following question, "What have you noticed since starting your cancer treatment (the EGFR inhibitor), any particular symptoms or reactions, positive or negative?" All interview data were audio-recorded, transcribed, and then independently coded and analyzed by two investigators. Results: Fifteen patients are the focus of this report, and all described cutaneous toxicity. Patients appeared troubled by the cosmetic aspect of these drug-induced skin changes, including their acneiform appearance, describing "little pimples with little, little pus in it." Notable were comments on hyperpigmentation, "I'm a black person but…. became darker." Furthermore, patients experienced physical symptoms: "it itches;" "it's like you stuck a pin in it;" "stinging;" and "burning;". Conclusion: Although cutaneous toxicity from EGFR inhibitors might be more difficult to visualize among darkly complected patients, the graphic descriptions offered in this qualitative study underscore the need for clinicians to heighten their awareness of such toxicity in African American/Black patients.

Role of antigen-presenting cells in non-ulcerated skin lesions caused by Leishmania (Leishmania) infantum chagasi

In Central America, infection by Leishmania (Leishmania) infantum chagasi causes visceral leishmaniasis and non-ulcerated cutaneous leishmaniasis (NUCL). This work aimed to evaluate the participation of subpopulations of antigen-presenting cells in skin lesions of patients affected by NUCL through double-staining immunohistochemistry using cellular and intracellular markers. Twenty-three skin biopsies from patients affected by NUCL were used. Histological sections stained by HE were used for histopathological study. Immunohistochemical studies were performed using primary antibodies against Langerhans cells, dermal dendritic cells, T lymphocytes, and the cytokines IL-12, IFN-γ, TNF-α, iNOS, and IL-10. The histopathological lesions were characterized by an inflammatory infiltrate, predominantly lymphohistiocytic, of variable intensity, with a diffuse arrangement associated with epithelioid granulomas and discreet parasitism. Double-staining immunohistochemistry showed higher participation of dendritic cells producing the proinflammatory cytokine IL-12 in relation to the other evaluated cytokines. Activation of the cellular immune response was marked by a higher density of CD8 Tc1-lymphocytes followed by CD4 Th1-lymphocytes producing mainly IFN-γ. The data obtained in the present study suggest that antigen-presenting cells play an important role in the in situ immune response through the production of proinflammatory cytokines, directing the cellular immune response preferentially to the Th1 and Tc1 types in NUCL caused by L. (L.) infantum chagasi.

Prognostic clinical and histopathological features of canine cutaneous epitheliotropic T-cell lymphoma

Canine cutaneous epitheliotropic T-cell lymphoma is a neoplasm with heterogeneous clinical and histopathological presentations. Survival times and responses to therapy are variable, and indicators to predict outcomes are lacking. Clinical and histopathological parameters from 176 archival cases from the University of Pennsylvania and University of Bern (2012-2018) were investigated for associations with clinical outcomes. Histopathological evaluation used digitized whole slide images and QuPath software. Cases included 107 female and 69 male dogs from 48 breeds, with a mean age of 10.4 years. Most common clinical signs were erythema (n = 131), crusting (n = 108), and scaling (n = 102). Affected sites were haired skin (n = 159), lip (n = 74), nasal planum (n = 49), and paw pads (n = 48). The median survival time (MST) was 95 days (1-850). Dogs had 4.26-fold and 2.82-fold longer MST when treated with chemotherapy and prednisone, respectively, than when receiving supportive care. Haired skin involvement (hazard ratio [HR]: 2.039, 95% confidence interval [CI]: 1.180-3.523), erosions/ulcers (HR: 1.871, 95% CI: 1.373-2.548), nodules (HR: 1.496, 95% CI: 1.056-2.118), and crusting (HR: 1.454, 95% CI: 1.061-1.994) were clinical parameters predicting poor outcomes, whereas complete posttherapeutic clinical remission (HR: 0.469, 95% CI: 0.324-0.680) and a stable disease (HR: 0.323, 95% CI: 0.229-0.456) were associated with longer survival. Histopathological features associated with the increased risk of death were extensive infiltration of the panniculus (HR: 2.865, 95% CI: 1.565-4.809), mitotic count ≥7/high-power field (HR: 3.027, 95% CI: 2.065-4.439), cell diameter ≥10.0 µm (HR: 2.078, 95% CI: 1.281-3.372), and nuclear diameter ≥8.3 µm (HR: 3.787, 95% CI: 1.647-8.707).

Cutaneous VCL::ALK fusion ovoid-spindle cell neoplasm

Cutaneous VCL::ALK fusion spindle (ovoid) cell tumor is unique. Recently emerged RAS::MAP tyrosine kinase fusion sarcomas more commonly involve subcutis, skeletal muscle and even bone. We share our experience with a novel cutaneous VCL::ALK spindle cell tumor. An 11-year-old male presented with a back pedunculated pink-red papule thought to be a pyogenic granuloma. Biopsy histopathology revealed an epithelial collarette with pedunculated tumor extending to deep dermis/subcutis interface. The combination of spindled and epithelioid cells, an ovoid myopericytoid appearance within myxoid to collagenous stroma, low to moderate MIB1 and focal S100 protein without SOX10 immunostaining, were suggestive of a novel RAS::MAPK tyrosine kinase fusion sarcoma that is well described. ALK immunostain being positive, a next-generation sequencing comprehensive fusion panel was performed to reveal a VCL::ALK fusion. While epithelioid fibrous histiocytoma shares this fusion and similar dermal location and collarette pedunculation, this and other entities were excluded by older patient age, deeper dermal involvement, ovoid-to-spindled morphology, central pericytoid vasculature, myxoid stroma, moderate cellularity with low to moderate MIB1 expression, superficial ulceration, and focal S100 protein expression. Complete excision was performed with favorable follow-up to date. This novel VCL::ALK fusion spindle (ovoid) cell tumor of the dermis is best considered as part of the recently emerged RAS::MAP tyrosine kinase fusion sarcomas.

Recent insights into comorbidities in atopic dermatitis

INTRODUCTION

The relationship between atopic dermatitis and atopic diseases such as food allergies, asthma, and allergic rhinitis in terms of co-occurrence, underlying mechanisms, and therapy is well documented. There is increasing evidence that atopic dermatitis is associated with non-atopic comorbidities such as cardiac, autoimmune, and neuropsychological comorbidities, as well as cutaneous and extracutaneous infections, establishing atopic dermatitis as a systemic disease.

AREAS COVERED

The authors reviewed evidence on atopic and non-atopic comorbidities of atopic dermatitis. A literature search was conducted in PubMed for peer-reviewed articles published until October 2022.

EXPERT OPINION

Atopic and non-atopic diseases coexist with atopic dermatitis more often than would be expected by chance. The effect of biologics and small molecules on atopic and non-atopic comorbidities may contribute to a better understanding of the relationship between atopic dermatitis and its comorbidities. Their relationship needs to be explored further to dismantle the underlying mechanism and move toward an atopic dermatitis endotype-based therapeutic approach.

Cutaneous Verrucous Carcinomas: A Review

Verrucous carcinoma (VC) is a relatively rare locally aggressive, slow-growing, well-differentiated squamous cell carcinoma with minimal metastatic potential and is most frequent in the mucosa. Although rarely reported on the skin, cutaneous verrucous carcinomas (CVC) can appear anywhere, most commonly on the feet. However, clinical and pathologic diagnosis of CVC has been confusing and challenging. It can easily be mistaken for benign or more malignant conditions such as giant condyloma acuminata, keratoacanthoma, and pseudoepithelioma-like hyperplasia or squamous cell carcinoma, resulting in inappropriate management. In this review, we describe the different aspects associated with CVC, including its pathogenesis and clinicopathologic features. The available evidence for the differential diagnosis and treatment of CVC is discussed, and specific management recommendations are made. After the treatment, careful follow-up examinations of the excised area should be performed at regular intervals.

Regulatory Requirements for the Development of Second-Entry Semisolid Topical Products in the European Union

The development of second-entry topical products is hampered by several factors. The excipient composition should be similar to the reference product because excipients may also contribute to efficacy. Conventional pharmacokinetic bioequivalence studies were not considered acceptable because drug concentrations are measured downstream after the site of action. There was no agreed methodology to characterize the microstructure of semisolids, and waivers of therapeutic equivalence studies with clinical endpoints were not possible. Only the vasoconstrictor assay for corticosteroids was accepted as a surrogate. This paper describes the implementation of the European Union's stepwise approach for locally acting products to cutaneous products, discusses the equivalence requirements of the EMA Draft Guideline on the Quality and Equivalence of Topical Products, and compares them with the US Food and Drug Administration recommendations. Step 1 includes the possibility of waivers for simple formulations based on in vitro data only (Q1 + Q2 + Q3 + IVRT). Step 2 includes step 1 requirements plus a kinetic study (TS/IVPT/PKBE) to compare the local availability of complex formulations. Step 3 refers to clinical studies with pharmacodynamic/clinical endpoints. As excipients may affect the local tolerability and efficacy of the products, the similarity of excipient composition is required in all steps, except where clinical endpoints are compared.

Leishmaniasis: Recent epidemiological studies in the Middle East

Leishmaniasis, one of the most neglected tropical diseases (NTDs), is the third most important vector-borne disease worldwide. This disease has a global impact and severity of the infection and is greatest in the Middle East. The agent of infection is a protozoan parasite of the genus, Leishmania, and is generally transmitted by blood-sucking female sandflies. In humans, there are three clinical forms of infection: (1) cutaneous (CL), (2) mucocutaneous (ML), and (3) visceral leishmaniasis (VL). This review aims to discuss the current epidemiological status of leishmaniasis in Saudi Arabia, Iraq, Syria, and Yemen with a consideration of treatment options. The elevated risk of leishmaniasis is influenced by the transmission of the disease across endemic countries into neighboring non-infected regions.

Cutaneous sarcoidosis mimicking pigmented purpuric dermatosis

Sarcoidosis is a systemic inflammatory disorder characterized by the formation of non-caseating granulomas. Cutaneous involvement of sarcoidosis is common and has a wide variety of clinical presentations. Herein, we present a case of cutaneous sarcoidosis mimicking pigmented purpuric dermatosis (PPD) in a 26-year-old female treated with topical tofacitinib cream and a literature review of all other reported cases of cutaneous sarcoidosis with PPD-like features.

A rapidly growing cutaneous malignant glomus tumor with a CCND3 mutation

Glomus tumors are rare mesenchymal neoplasms composed of cells resembling the glomus body. They are most frequently seen in subungual regions but have been reported to arise in almost every anatomic location. Malignant glomus tumors, also called glomangiosarcomas, of cutaneous origin are exceedingly rare with only 47 reported cases. The genetic alterations that lead to the development of cutaneous malignant glomus tumors are not well understood. Small studies report glomus tumors with mutations in glomulin (GLMN), NF1, BRAF, NOTCH, PDGFRB, KRAS, and SMARCB1. These mutations have mostly been studied in deep or visceral glomus tumors. We report a case of a cutaneous malignant glomus tumor with a CCND3 point mutation identified on next generation sequencing, without any of the previously described genetic mutations. CCND3 mutations that cause cyclin D3 amplification may prove to be targets for CDK4/6 inhibitors in the treatment of malignant glomus tumors.