Cicatricial alopecias: Pathogenesis, classification, clinical features, diagnosis, and management
Jerry Shapiro, Nina Otberg in Hair Loss and Restoration, 2015
Cicatricial or scarring alopecias comprise a diverse group of scalp disorders that result in irreversible hair loss. All scarring alopecias are characterized clinically by a loss of follicular ostia and pathologically by a replacement of hair follicles with fibrous tissue. A basic knowledge of follicular anatomy is important in the understanding of cicatricial alopecias, because the location of the destructive process is crucial in determining the irreversibility of alopecia. Primary cicatricial alopecia refers to a group of idiopathic inflammatory diseases, characterized by a folliculocentric inflammatory process that ultimately destroys the hair follicle. Primary cicatricial alopecias are characterized by an inflammatory process affecting the upper, permanent portion of the follicles, particularly around the pluripotent stem cells of the bulge area, the sebaceous gland, and the infundibulum. Primary cicatricial alopecia most commonly affects the central and parietal scalp before progressing to other sites of the scalp.
Anatomy
Giuseppe Micali, Pompeo Donofrio, Maria Rita Nasca, Stefano Veraldi in Vulval Dermatologic Diagnosis, 2015
The vulva consists of the mons pubis, labia majora, labia minora, the hymen, the clitoris, the vestibule of the vagina, the urethral orifice, Skene’s glands, Bartholin’s glands, and the vestibular bulbs. The mons pubis, the perineum, and the labia share an ectodermal origin and have a keratinized, stratified, squamous epithelial structure with hair follicles, sebaceous glands, and sweat glands, similar to those of other skin sites. The degree of thickness of the vulvar skin epidermal keratinization progressively decreases from the outer part, the labia majora, to the inner part, the labia minora. The vulvar vestibule, conversely, is nonkeratinized and derived from the endodermal fold.
Tumors of the Epidermis
Omar P. Sangueza, Sara Moradi Tuchayi, Parisa Mansoori, Saleha A. Aldawsari, Amir Al-Dabagh, Amany A. Fathaddin, Steven R. Feldman in Dermatopathology Primer of Cutaneous Tumors, 2015
Epidermal nevus is a term that encompasses hamartomatous proliferations of epithelium that originate from embryonal ectoderm. They are classified on the basis of the main histologic component: keratinocytes, sebaceous gland, pilosebaceous unit, eccrine gland, or apocrine gland. Clear cell acanthoma is a benign epidermal neoplasm composed of keratinocytes with ample pale cytoplasm and centrally placed nuclei. It consists of a well-demarcated, solitary, shiny, and brown to orange papule or nodule. Inverted Follicular Keratosis is an uncommon benign tumor of the follicular infundibulum that can be confused, both clinically and histologically, with several benign and malignant skin conditions. Seborrheic keratoses are the most common benign skin tumor in older individuals characterized by well-demarcated papules with a verrucous surface. Warty dyskeratoma is a benign papulonodular lesion characterized by an endophytic proliferation of squamous epithelium, typically occurring in relation to a folliculosebaceous unit and showing prominent areas of acantholysis.
Differentiation of the sebaceous gland
Published in Dermato-Endocrinology, 2009
The sebaceous gland is renewed throughout adult life and homeostasis of this particular organ is controlled by a precise interplay of hormones, cytokines, signalling molecules and mediators of the lipid metabolism. Although the true function of sebaceous glands has yet to be fully determined, recent evidence demonstrated that normal homeostasis of the sebaceous gland and functional lipid metabolism of sebocytes is crucial for maintenance of the skin barrier. In addition, analysis of mutant mouse models revealed a close interdependency of the sebaceous gland with hair follicles because abnormal morphogenesis of sebaceous glands often results in degeneration of hair follicle structures. Anomalous regulation of sebaceous glands is involved in the pathogenesis of acne, one of the most prevalent human diseases, or could lead to formation of sebaceous hyperplasia and tumours. This review highlights some of the recent findings on the importance of signalling pathways controlling morphogenesis and differentiation of the sebaceous gland in vivo.
Recent advances in the endocrinology of the sebaceous gland
Published in Dermato-Endocrinology, 2017
Attila G. Szöllősi, Attila Oláh, Tamás Bíró, Balázs István Tóth
The sebaceous gland, long considered an evolutionary relic with little-to-no physiological relevance in humans, has emerged in recent decades as a key orchestrator and contributor to many cutaneous functions. In addition to the classical physico-chemical barrier function of the skin against constant environmental challenges, a more novel, neuro-immune modulatory role has also emerged. As part of the complex intercellular communication network of the integumentary system, the sebaceous gland acts as a “relay station” in the skin for many endocrine factors. This review aims to offer a comprehensive overview of endocrine effects and subsequent interactions on this much maligned mini-organ.
Microcystic adnexal carcinoma of the orbit mimicking pagetoid sebaceous gland carcinoma
Published in Orbit, 2018
Bipasha Mukherjee, Nirmala Subramaniam, Krishna Kumar, Pratheeba Devi Nivean
Microcystic adnexal carcinoma (MAC) is a rare malignancy of sweat glands that has been reported most often on the face in the form of a cutaneous lesion, with the potential for deeper invasion. The synonyms of MAC include sclerosing sweat duct carcinoma, syringomatous carcinoma, and malignant syringoma. Clinically, MAC in the periocular area has been misdiagnosed as basal cell carcinoma, squamous cell carcinoma, or even chalazia. We report a case of MAC presenting clinically as sebaceous gland carcinoma with pagetoid spread for the first time in literature.