Near-infrared radiation causes sebaceous gland enlargement along with an ROS-dependent augmentation of epidermal growth factor receptor expression in hamsters.

As near-infrared radiation (NIR), which is a composition of sunlight with an 780-1400 nm wavelength, is associated with skin aging such as wrinkles and slacks, the biological actions of NIR with high dermal penetration remains unclear. In the present study, we found that NIR irradiation (40 J/cm2 ) at different levels of irradiance (95-190 mW/cm2 ) using a laboratory device with a xenon flash lamp (780-1700 nm) caused sebaceous gland enlargement concomitantly with skin thickening in the auricle skin of hamsters. The sebaceous gland enlargement resulted from the proliferation of sebocytes due to an increase in the number of proliferating cell nuclear antigen (PCNA)- and lamin B1-positive cells in vivo. In addition, NIR irradiation transcriptionally augmented the production of epidermal growth factor receptor (EGFR) accompanied with an increase in the reactive oxygen species (ROS) level in hamster sebocytes in vitro. Furthermore, the administration of hydrogen peroxide increased the level of EGFR mRNA in the sebocytes. Therefore, these results provide novel evidence that NIR irradiation causes the hyperplasia of sebaceous glands in hamsters by mechanisms in which EGFR production is transcriptionally augmented through ROS-dependent pathways in sebocytes.

The role of hypothalamus-pituitary-adrenal (HPA)-like axis in inflammatory pilosebaceous disorders.

Skin is the largest peripheral endocrine organ and functions as a hormone target and endocrine gland. A cutaneous hypothalamus-pituitary-adrenal (HPA)-like axis enables the skin to respond to stress and regulates its steroidogenic activity. The pilosebaceous unit is a site for production and metabolism of a number of steroid hormones, including stress and sex hormones. This is an overview of the important role that the cutaneous HPA-like-axis plays in the pathogenesis and treatment of inflammatory pilosebaceous disorders, including acne, rosacea, seborrheic dermatitis, and hidradenitis suppurativa.

1H NMR-based lipidomics of rodent fur: species-specific lipid profiles and SCD1 inhibitor-related dermal toxicity.

A method is described that allows noninvasive identification and quantitative assessment of lipid classes present in sebaceous excretions in rodents. The method relies on direct high-field proton NMR analysis of common group lipid protons in deuterated organic solvent extracts of fur. Extracts from as little as 15 mg of fur from rat, mouse, and hamster provided acceptable results on a 600 MHz NMR equipped with a cryogenically cooled proton-observe probe. In rats, sex- and age-related differences in lipid composition are larger than differences in fur collected from various body regions within an individual and much larger than interanimal differences in age- and sex-matched specimens. The utility of this method to noninvasively monitor drug-induced sebaceous gland atrophy in rodents is demonstrated in rats dosed with a stearoyl-CoA desaturase 1 (SCD1) inhibitor. In this model, a 35% reduction in sebum lipids, extracted from fur, was observed. Finally, structural elucidation of cholesta-7,24-dien-3ß-ol ester as the most prominent, previously unidentified sebum sterol ester in male Syrian hamsters is described. The utility of this method for drug and cosmetic safety and efficacy assessment is discussed.

Intratarsal keratinous cysts of the meibomian gland (a sebaceous duct cyst): report of 2 cases.

Intratarsal keratinous cyst of the meibomian gland is a recently described entity that recurs if not completely excised. Herein, we report 2 cases and discuss their diagnosis and management: (1) A 57-year-old man with a recurrent mass of the upper eyelid treated with incision and drainage as a chalazion for more than 5 years and (2) An 85-year-old man presented with a slow growing nodule of the upper eyelid. Exploration via the eyelid crease approach revealed cysts fixed to the tarsus that were completely excised with a portion of the anterior tarsus. Histologically, these cysts exhibited a keratinizing squamous epithelium without a granular layer (trichilemmal keratinization), were lined by an eosinophilic undulating cuticle, contain string-like keratin debris, and had a fibrous wall without sebaceous lobules. All epithelial components strongly expressed high-molecular weight keratins, whereas the lining, cuticle, and keratin contents strongly expressed carcinoembryonic antigen. No recurrence has occurred 7 and 12 months postoperatively. The location and clinicopathologic findings of intratarsal keratinous cysts distinguish it from sebaceous tumors, steatocystoma simplex, epidermoid cyst, and dermoid cyst. However, like steatocystomas, intratarsal keratinous cysts exhibit a sebaceous duct phenotype. The anterior lid crease approach with partial tarsectomy seems to be an effective treatment.

The clinical, histological and immunohistochemical characteristics and nomenclature of meibomian gland ductal cysts (intratarsal keratinous cysts) and eyelid steatocystomas.

PurposeMeibomian gland ductal cysts (MGDCs) and steatocystomas are epithelial lined, keratin-containing lesions of the eyelids. MDGCs are variably called tarsal keratinous cysts, intratarsal keratinous cysts of the meibomian glands, intratarsal inclusion cysts, epidermal cysts and epidermoid cysts. Both lesions are poorly described in the literature. We report a series of seven MGDC and steatocystomas, and examine their clinical, pathological and immunohistochemistry features and their management and outcomes.Patients and methodsA retrospective review of case notes and histopathology slides of all MGDCs and steatocystomas identified at one major histopathology service in South Australia between 2013 and 2015.ResultsSeven cases were identified, with an average age of 64. The lesions range from 4 to 18 mm diameter and are firm, well-circumscribed and non-tender, and sometimes the keratin-filled cyst protrudes visibly under the tarsal conjunctiva. Two cases were previously misdiagnosed as chalazia but recurred after incision and curettage. Histologically, these lesions are lined by squamous epithelium but lack a well-formed stratum granulosum and can be distinguished by their immunohistochemical staining characteristics. Complete excision, including a wedge of underlying tarsal plate for MDGCs, is curative for with a follow up of 12-36 months.ConclusionsMGDCs and steatocystomas should be included in the differential of benign eyelid lesions. Diagnosing and differentiating these lesions from chalazia is important for determining the optimal management strategy.

Association of meibum oleic acid with meibomian seborrhea.

PURPOSE: We sought to determine whether patient meibum fatty acid unsaturation is associated with meibomian gland secretion consistency. METHODS: Meibomian gland secretions were dissolved in chloroform and separated into lipid classes by thin-layer chromatography. Fatty acids in individual lipid classes were characterized by gas chromatography after transmethylation. RESULTS: Meibum from patients with meibomian seborrhea was higher, and meibum from patients with meibomian keratoconjunctivitis (meibomianitis) was lower in the monounsaturated fatty acid, oleic acid, than that of other disease groups and normal subjects. CONCLUSION: Our results strongly suggest that the melting characteristics of meibum, influenced primarily by the amount of oleic acid in wax and sterol esters and free fatty acids, greatly influence the consistency of meibomian gland secretions.

Transient postnatal secretion of androgen hormones is associated with acne and sebaceous gland hypertrophy in early infancy.

CONTEXT: Sebaceous gland hypertrophy (SGH) and acne-like skin eruptions are frequent during the first months of life, yet the etiology and prevalence of these conditions in infants are not clear. OBJECTIVE: The objective of the study was to evaluate the association of postnatal androgens with SGH and acne in infants. DESIGN: This was a longitudinal, monthly follow-up from 1 wk (D7) to 6 months of age (M1-M6). PATIENTS: Patients included 54 full-term (FT; 26 boys) and 48 preterm (PT; gestational age at birth 27.7-36.6 wk, 22 boys) infants. MAIN OUTCOME MEASURES: The occurrence of SGH (present/absent) and acne (5-10, 10-50, and >50 papules) was registered and compared with urinary levels of dehydroepiandrosterone and its sulphate and testosterone measured by liquid chromatography-tandem mass spectrometry. RESULTS: SGH was observed in 89% of FT and 96% of PT infants (P = 0.28). Acne (more than five papules) was observed in 91% of FT infants and in 75% of PT infants (P = 0.06). Both SGH and acne were associated with developmental rather than calendar age: SGH was limited to postmenstrual age less than 46 wk and acne was not observed less than 37 wk of postmenstrual age. Urinary androgen levels showed severalfold differences in magnitude between sexes and between the FT and PT groups. After grouping according to sex and maturity, the occurrence of SGH and the severity of acne were associated with higher urinary dehydroepiandrosterone sulphate and testosterone levels in each group. CONCLUSIONS: SGH and acne are common during the first months of life and associated with endogenous, physiologically elevated levels of androgens originating from the adrenals and gonads. These data suggest a novel role for postnatal androgen secretion in infancy.

The white caruncle: sign of a keratinous cyst arising from a sebaceous gland duct.

PURPOSE: To describe an acquired, smooth white lesion of the caruncle and to underscore the role of subsurface keratinizing squamous epithelium in its formation. METHODS: Clinical photographic documentation, histopathologic evaluation, and immunohistochemical staining of an excised specimen from a 25-year-old woman. RESULTS: A cyst was found that was lined by keratinizing squamous epithelium without a keratohyaline layer (trichilemmal keratinization), typical of lesions of the pilosebaceous unit. A portion of the cyst's lining was replaced by granulomatous inflammation resulting from an earlier spontaneous partial rupture. Ki-67 immunolabeling demonstrated relatively few nuclei in S-phase (DNA synthesis) in comparison with the overlying epithelium, thereby suggesting an obstructive, nonproliferative cause for the cyst. CONCLUSION: A white caruncular lesion is a very rare finding according to the literature. It is most likely caused by a cyst lined by squamous epithelium elaborating trichilemmal-type keratin. A sebaceous gland duct was established as the source for the current lesion.

Cytokeratin and filaggrin expression in nevus comedonicus.

To elucidate the pathogenesis of abnormal keratinization in nevus comedonicus, we performed an immunohistochemical study using antikeratin and antifilaggrin (filament-aggregating protein) antibodies. There were no significant differences between nevus comedonicus and normal skin in cytokeratin expression. Although filaggrin was only detected in the granular layer in open comedones, filaggrin was detected in both superficial cells and also intermediate cells in closed comedones, suggesting that filaggrin is involved in the formation of closed comedones. The disorder of terminal differentiation related to filaggrin may play a role in the pathogenesis of abnormal keratinization in nevus comedonicus.

An unusual hamartoma of the folliculosebaceous-apocrine unit: a case report.

Hamartoma is a neoplasm-like lesion composed of an abnormal mixture of tissues native to the area. We report on an unusual example of a hamartomatous lesion that showed an abnormal mixture of elements of the folliculosebaceous-apocrine unit and arrector pili muscle. A 13-year-old female presented with two nodules situated 2 cm apart on the lower leg that were present since birth. The patient reported some enlargement and slight pain of the otherwise asymptomatic lesions during 2 years, before they were surgically removed. The patient obviously had no skin problems afterwards; her 12-year follow-up was significant for leucopenia and nephrolithiasis. The biopsies from both lesions looked identical. Each lesion was biphasic, i.e. composed of a predominant mesenchymal component and epithelial elements. The mesenchymal part resembled a leiomyoma, or in minor areas, the constituting cells had a myofibroblastic appearance. Encased within the mesenchymal component were large infundibulocystic structures and plentiful grouped and scattered roundish solid epithelial nodules, duct-like, glandular, and tubular elements. Some of the epithelial structures were reminiscent of those seen in tubular apocrine adenoma; others resembled syringomatous elements. We interpreted this unusual lesion as a hamartoma of the folliculosebaceous-apocrine unit.