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Mucocutaneous Junction (mucocutaneou + junction)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Dermoscopy of pigmented lesions on mucocutaneous junction and mucous membrane

BRITISH JOURNAL OF DERMATOLOGY, Issue 6 2009
J. Lin
Summary Background, The dermoscopic features of pigmented lesions on the mucocutaneous junction and mucous membrane are different from those on hairy skin. Differentiation between benign lesions and malignant melanomas of these sites is often difficult. Objective, To define the dermoscopic patterns of lesions on the mucocutaneous junction and mucous membrane, and assess the applicability of standard dermoscopic algorithms to these lesions. Patients and methods, An unselected consecutive series of 40 lesions on the mucocutaneous junction and mucous membrane was studied. All the lesions were imaged using dermoscopy devices, analysed for dermoscopic patterns and scored with algorithms including the ABCD rule, Menzies method, 7-point checklist, 3-point checklist and the CASH algorithm. Results, Benign pigmented lesions of the mucocutaneous junction and mucous membrane frequently presented a dotted-globular pattern (25%), a homogeneous pattern (25%), a fish scale-like pattern (18·8%) and a hyphal pattern (18·8%), while melanomas of these sites showed a multicomponent pattern (75%) and a homogeneous pattern (25%). The fish scale-like pattern and hyphal pattern were considered to be variants of the ring-like pattern. The sensitivities of the ABCD rule, Menzies method, 7-point checklist, 3-point checklist and CASH algorithm in diagnosing mucosal melanomas were 100%, 100%, 63%, 88% and 100%; and the specificities were 100%, 94%, 100%, 94% and 100%, respectively. Conclusion, The ring-like pattern and its variants (fish scale-like pattern and hyphal pattern) are frequently observed as well as the dotted-globular pattern and homogeneous pattern in mucosal melanotic macules. The algorithms for pigmented lesions on hairy skin also apply to those on the mucocutaneous junction and mucous membrane with high sensitivity and specificity. [source]

2432: Histological characteristics of the posterior lid margin

ACTA OPHTHALMOLOGICA, Issue 2010
N KNOP
Purpose The structure of the lid margin is insufficiently understood and defined although it is of obvious importance for ocular surface integrity. In particular the histological structure of the tissues of the normal lid margin and their zonal differentiation is partly unclear. Methods The structure and function of the different zones at the posterior lid margin are explained with a focus on dry eye disease, based on the available literature on the lid margin together with own findings on the histology of normal and pathological tissues from the human lid margin. Results The Meibomian glands (MG) that are of particular significance for the integrity of the ocular surface open still within the cornified epidermis. Their obstructive dysfunction (MGD) is a main cause for dry eye disease. The orifice is followed by the mucocutaneous junction (MCJ) that extends from the abrupt termination of the epidermis to the crest of the inner lid border. The physiological vital stainable line of Marx represents its surface and can be used as a diagnostic tool for the location and functionality of the MG orifices and lacrimal puncta. The marginal conjunctiva starts at the crest of the inner lid border and forms a thickened epithelial cushion. This is the point in closest apposition to the globe, represents the zone that wipes the bulbar surface and distributes the thin pre-ocular tear film. It is hence termed as the lid wiper and pathological alterations that result in a vital staining are a sensitive early indicator of dry eye disease. Conclusion The margin of the eyelid is an important but yet underestimated structure for the maintenance of the pre-ocular tear film and of utmost importance for the preservation of ocular surface integrity and for development of dry eye disease. Support DFG KN317/11 [source]

2433: A revolutionary hypothesis to explain Marx's line and progressive disease at the lid margin

ACTA OPHTHALMOLOGICA, Issue 2010
AJ BRON
Purpose The conjunctiva of the lid margin is protected from direct exposure to the atmosphere, by the tear meniscus. We examine the pathophysiological consequences of evaporation from this compartment. Methods A consideration of empirical data. Results The concave meniscus thins progressively to the point where it is pinned at the mucocutaneous junction (MCJ). We predict that, as a result, over the interblink period, evaporation generates a solute gradient which peaks behind the MCJ and is amplified over multiple cycles of the blink. We hypothesise that this creates a hyperosmolar state here which: i. stresses epithelial cells behind the MCJ, ii. stimulates a high cell turnover and iii. leads to immaturity of the surface cells and their glycocalyx. This is considered to explain an increased permeability to dyes at this site (rose bengal, lissamine green and fluorescein) and the stainability with dyes which is termed Marx's line. This gradient mechanism could also concentrate proteins, such as inflammatory mediators, at this location. Conclusion Since Marx's line lies directly behind the terminal Meibomian ducts and acini, chronic stress in this region is further invoked to explain forward migration of Marx's line and the MCJ which occurs with age and the induction of primary Meibomian gland dysfunction. Arguments are put forward to explain how this mechanism might be accentuated in dry eye and how the globe might be protected from this gradient effect in the region of the ,black line', where the tear film is segregated from the meniscus after the blink. Factors pro and con the hypothesis are discussed. [source]

Structure of the lid margin in laboratory animals

ACTA OPHTHALMOLOGICA, Issue 2008
N KNOP
Purpose The eye lid margin is of great importance for the spreading and the limitation of the tears. The so called lid wiper which is a specialized zone at the inner lid border directly apposed to the corneal surface for spreading the preocular tear film has, at present, only been described for the human conjunctiva. We have investigated common laboratory animals (rat and rabbit) for the presence of such a zone. Methods Conjunctival whole-mount specimens and total bulbi were investigated by serial section histology in ten rats (DA and Lewis) and in ten rabbits (NZW and Chinchilla). Results The stratified squamous keratinised epidermis of the free lid margin showed a sharp transition with loss of the keratin layer at the level of the meibomian glands. Close to the inner lid border it was replaced by a small zone of an optically denser epithelium covered by para-keratinised cells. This area represented the mucocutaneous junction (MCJ) equivalent to the line of Marx in the human. The MCJ rapidly transformed into a thickened 8-12 cell layered stratified epithelium of that formed a cushion-like epithelial elevation, reclined sharply towards the inner lid border and hence formed a typically relatively sharp lip-like edge. The lid-wiper epithelium showed species-specific differences in morphology (cuboidal with goblet cells in the rabbit versus squamous without goblet cells in the rat) but it extended all along the lid margin in both species. Conclusion At the inner border of the upper and lower lid of rat and rabbit, several zones of different morphology occur similar to the human including a lid-wiper structure. Since lid wiper epitheliopathy was shown as a sensitive early indicator for human dry eye syndrome its investigation may be useful for future research in dry eye models of laboratory animals. [source]

Fixed drug eruption in Nigeria

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 9 2006
Edith N. Nnoruka MBBS
Fixed drug eruption (FDE) causes cosmetic embarrassment in Nigerian patients, particularly when the characteristic hyperpigmented patches affect the face and lips. Drugs that have been implicated in the etiology of FDE, and the sites of lesions, may vary from country to country. Antimalarials, such as Fansidar, Fancimef, Maloxine, Amalar, and Metakelfin, were the most common offending agents, accounting for 38% of FDEs, followed by trimethoprim + sulfamethoxazole (co-trimoxazole) (28%), dipyrones (10%), Butazolidin (6%), thiacetazone (6%), metronidazole (4%), paracetamol (3%), and naproxen (3%). Lesions induced by the combination of sulfadoxine and pyrimethamine (in antimalarials) mainly involved the face and lips. In most cases, patients took these sulfa-containing antimalarials in combination with numerous other drugs, particularly analgesics. Unlike chloroquine-induced pruritus, which affects most Africans, the association between antimalarials and FDE has not been well documented in our region. Co-trimoxazole was associated more often than antimalarials with FDEs involving the mucocutaneous junctions of the genitalia and lips. Males with genital lesions on the glans penis represented 11 (48%) of those with co-trimoxazole hypersensitivity. The trunk and limbs were affected mainly by pyrazoles and Butazolidin, respectively; however, solitary lesions on the trunk were usually due to co-trimoxazole, whereas solitary lesions on the limbs were associated with Butazolidin. [source]