Others may warrant more thorough examination and biopsy for histopathological examination (looking at a sample of skin under a microscope to detect unique cellular features). For example, a clinician may want to determine whether a pigmented nevus is a type of melanocytic nevus, dysplastic nevus, or melanoma as some of these skin lesions pose a risk for malignancy. The ABCDE criteria (asymmetry, border irregularity, color variegation, diameter > 6 mm, and evolution) are often used to distinguish nevi from melanomas in adults, while modified criteria (amelanosis, bleeding or bumps, uniform color, small diameter or de novo, and evolution) can be used when evaluating suspicious lesions in children. In addition to histopathological examination, some lesions may also warrant additional tests to aid in diagnosis, including special stains, immunohistochemistry, and electron microscopy. Typically, the nevi that exist since childhood are harmless. Differential diagnoses
Hypermelanotic nevi must be differentiated from other types of pigmented skin lesions, including:
Lentigo simplex
Solar lentigo
Café au lait macule
Ink-spot lentigo
Mucosal melanotic macule
Mongolian spot (dermal melanocytosis)

Management
The management of a nevus depends on the specific diagnosis, however, the options for treatment generally include the following modalities:

Observation
Destruction
Chemical peels
Cryotherapy
Dermabrasion
Electrodessication
Laser ablation

Surgery
The decision to observe or treat a nevus may depend on a number of factors, including cosmetic concerns, irritative symptoms (e.g., pruritus), ulceration, infection, and concern for potential malignancy. Syndromes
The term nevus is included in the names of multiple dermatologic syndromes:

Basal cell nevus syndrome
Blue rubber bleb nevus syndrome
Dysplastic nevus syndrome
Epidermal nevus syndrome
Linear nevus sebaceous syndrome

Etymology
A naevus may also be spelled nevus. The plural is nevi or naevi.
It is about equipotent in blocking beta1- and beta2- receptors.The amount of alpha to beta blockade depends on whether labetalol is administered orally or intravenously (IV). Orally, the ratio of alpha to β blockade is 1:3. Intravenously, alpha to β blockade ratio is 1:7. Thus, the labetalol can be thought to be a beta-blocker with some alpha-blocking effects. By comparison, labetalol is a weaker β-blocker than propranolol, and has a weaker affinity for alpha-receptors compared to Phentolamine.Labetalol possesses intrinsic sympathomimetic activity. In particular, it is a partial agonist at beta2- receptors located in the vascular smooth muscle. Labetalol relaxes vascular smooth muscle by a combination of this partial beta2- agonism and through alpha1- blockade. Overall, this vasodilatory effect can decrease blood pressure.Similar to local anesthetics and sodium channel blocking antiarrhythmics, labetalol also has membrane stabilizing activity. By decreasing sodium entry, labetalol decreases action potential firing and thus has local anesthetic activity. Physiological action
The physiological effects of labetalol when administered acutely (intravenously) are not predictable solely by their receptor blocking effect, i.e. blocking beta1- receptors should decrease heart rate, but labetalol does not. When labetalol is given in acute situations, it decreases the peripheral vascular resistance and systemic blood pressure while having little effect on the heart rate, cardiac output and stroke volume, despite its alpha1-, beta1- and beta2- blocking mechanism. These effects are mainly seen when the person is in the upright position.Long term labetalol use also has different effects from other beta-blocking drugs. Other beta-blockers, such as propranolol, persistently reduce cardiac output during exercise.