"Pathway Leap": A New Molecular Phenomenon to Consider in the Pathogenesis of Melanocytic Tumors.

Introduction: The current WHO classification of melanocytic tumors distinguishes 9 pathogenic routes. This classification is based on the conceptual interpretation that melanocytic tumors evolve from benign counterparts, accumulating mutations, eventually developing into melanomas with metastatic and potentially lethal capacity. In this article, we present a molecular study of 2 melanocytic tumors that suggest a "leap" from pathogenic routes IV to I.

Conceptual Contextualization of Neutrophilic Dermatoses.

Neutrophilic dermatoses are defined as inflammatory skin diseases characterized by sterile infiltration of polymorphonuclear neutrophils into various cutaneous layers. Although, in many cases, neutrophilic dermatoses represent the cutaneous counterpart of autoinflammatory diseases, this is not always the case, and there are other causes associated with this group of diseases, such as the administration of certain drugs or an underlying tumor. However, understanding the autoinflammatory context in which most of these entities develop, as well as their close relationship with autoimmunity, is key to comprehending their pathogenesis.

Two Cases of FAVA With an Uncommon Localization in Adults.

The fibroadipose vascular anomaly (FAVA) is a relatively unknown vascular anomaly in the realm of adult dermatopathology. Despite its intramuscular location, dermatologists often encounter cases, approaching them surgically under the presumption of a potential lipoma. This entity was first described in 2014, and consequently, many FAVA cases may be concealed in our archives under diagnoses of other entities that require differential diagnoses, such as intramuscular fast-flow vascular anomaly.

Selective Clonal Regression After Interferon Therapy in Metastatic Melanoma.

Regression (total or partial) is a common phenomenon in melanoma. From a pathogenic perspective, it is highly complex and only partially understood, involving aspects of both the tumor and the individual. One of the determining factors is the clonal selection of the tumor, wherein some clones within the tumor survive while others perish.

Cocaine-Induced Plasma Cell Orificial "Dermatomucositis": A More Accurate Descriptive Term for a Clearly Dermatological Entity.

Although the involvement of the nasal passages and nasal septum in cocaine users has been known for decades, a new presentation affecting the nostrils and upper lip with an inflamed appearance has recently been documented. The authors who identified this presentation termed it "cocaine-related plasma cell mucositis" due to the abundance of plasma cells in the infiltrate. In this article, we present a second case and emphasize the dermal involvement of the lip, leading us to consider the condition as a genuine dermatomucositis.

The dermal deposits in the finger of the Holy Roman Emperor Charles I of Spain and V of Germany.

Charles I of Spain and V of Germany was one of the most prominent figures in Christendom. The vast empire ruled by the monarch extended across multiple continents. However, the final years of his life were overshadowed by depression and incapacitating joint degeneration, leading him to retire to the Monastery of Yuste in Cáceres, Spain.

[Main Types of Cysts in Dermatopathology: Part 1].

Cystic structures represent one of the most common findings in dermatopathology. These encompass both cystic tumors and pseudocysts resulting from the accumulation of certain substances, such as mucin. In a two-part series (of which this is the first part), we have reviewed the principal types of cysts and pseudocysts that may be observed in cutaneous biopsies, examining their histopathological features and primary differential diagnoses.

Connexin 43 in Dermatofibroma and Dermatofibrosarcoma Protuberans: Diagnostic, Pathogenic, and Therapeutic Implications.

Connexins play a crucial role in the formation of gap junctions that connect cells to each other, as well as cells to the surrounding environment. In recent years, connexin 43 has been extensively studied in various human tumors. In this study, we conducted an immunohistochemical analysis to evaluate the expression of connexin in 16 dermatofibromas (DFs) and 13 dermatofibrosarcoma protuberans (DFSP).

Basic Concepts in Nail Pathology.

Understanding nail pathology is complex for general pathologists and even for those dermatopathologists who do not receive many nail samples in their laboratories. In this article, we attempt to review some of the primary entities in nail pathology with the aid of modern interpretations of nail histology and embryology. We also provide diagrams that can aid in comprehending this field of pathology.

CD30 in Cutaneous Pathology.

The discovery of CD30 as a diagnostic marker was essential in the identification of not only some lymphomas but also many other solid tumors and benign reactive conditions. Many CD30+ cutaneous disorders and tumors have been categorized since the identification of the marker. With the design of targeted therapies against CD30+ tumoral cells, the interest in CD30 determination was not only diagnostic but also mainly therapeutic.

Axillary Cutaneous Hemosiderosis in a Patient With Hyperhidrosis, After Intravenous Iron Infusion.

Hemosiderosis consists of an iron deposit in tissues, which does not cause organic damage to them. However, in the case of the skin, being an organ exposed to sight, siderosis can produce a brownish coloration that is aesthetically discomforting for the individual. Most cutaneous sideroses are because of venous insufficiency with hemorrhagic extravasation.

The Dermatopathology Books Before Unna.

Unna's book on dermatopathology was the one that achieved the greatest recognition in medicine and influenced the largest number of dermatopathologists in Europe at that time. However, several previous texts also gathered the requirements to be considered dermatopathological books. In this manuscript, we briefly examine some of the most relevant features of the dermatopathology books written by Simon, Leloir and Vidal, Auspitz, Bärensprung, and Jackson.

Top 10 Differential Diagnoses for Desmoplastic Melanoma.

Background: Desmoplastic melanoma is a rare subtype of melanoma mainly appearing on sun-exposed skin. Clinically, it is many times non-pigmented and therefore the diagnosis is often not suspected.

Methods: Review article.

Ungual Keratoacanthoma With Features of Regression.

Ungual keratoacanthoma (UKA) is an infrequent tumor. Different from keratoacanthoma in other parts of the skin, UKA rarely regresses, and grows aggressively with common destruction of the subjacent phalanx. Reported cases of UKA with features of regression are exceptional, and even dermatopathologists with reputed experience in nail pathology admit to having seen very few cases.

Genetic Studies on a Case of Eruptive Disseminated Spitz Nevus and Review of Other 33 Cases.

Eruptive disseminated Spitz nevus is an uncommon presentation of Spitz nevi. Only a few tens of cases have been published and only 6 of them have genetic studies. We present an additional case of a 29-year-old woman with dozens of Spitz nevi which had appeared since she was aged 10 years.