A Panoply of Nevi

December 31, 2006

An area of pigment loss in the skinand surrounding hair is noted on thehead of a 10-year-old boy. Examinationof the vertex of the scalp revealsa nevus encircled by depigmentation.

Case 1:

An area of pigment loss in the skinand surrounding hair is noted on thehead of a 10-year-old boy. Examinationof the vertex of the scalp revealsa nevus encircled by depigmentation.Can you identify this lesion?

Case 2:

During a routine skin examination,a suspicious-looking pigmented lesionis noted on the upper back of a27-year-old man. The 4-cm, irregularlyshaped lesion is composed of multiple,small dark brown macules.Is this lesion likely to bemalignant?

Case 1:

This is a halo, or Sutton,nevus. The differential diagnosis of adepigmented area includes vitiligoand pityriasis alba; however, the centrallocation of a pigmented lesion in around, sharply demarcated area of almostcomplete pigment loss is uniqueto a halo nevus.The lesion gradually resolves,with repigmentation of the skin andhair and disappearance of the nevus.These nevi are usually benign; however,evaluate the central nevus usingthe "ABCD" rules for melanoma detection(

Table

).

Case 2:

This is a nevus spilus, a typeof congenital nevus. Because of thelesion's unusual clinical appearance,the differential diagnosis includes malignantmelanoma. However, a nevusspilus is a benign lesion that is associatedwith a very low rate of malignanttransformation. The patient also hasmultiple darkly pigmented nevi on hisback with a background of freckling.

Case 3:

The parents of a 6-year-old boy areconcerned about a small reddish lesionon the lateral side of their son'snose. The lesion has grown slightlylarger and more prominent overtime.What is your clinical impression?

Case 3:

A

spider angioma

, or

nevus araneus

, is a benign lesioncaused by dilated arterioles that supplyradiating surface telangiectases.The diagnostic sign is a central, oftenpulsatile, red papule; when the centeris compressed with a pen point orother blunt, narrow object, the entirelesion blanches. These features helpdistinguish spider angiomas fromsimple telangiectases.In children, spider angiomastypically fade over time. They can betreated by electrocautery or lasersurgery, if desired for cosmesis.Spider angiomas can also be inducedby various factors, includingexogenous estrogen intake, alcoholism,pregnancy, or thyrotoxicosis.

Case 4:

Two skin-colored papules--one at themedial right eyebrow, the other justabove the lateral half of the same eyebrow--have been present for years ina 34-year-old woman. The asymptomaticlesions may have enlarged withtime.What are these lesions?

Case 4:

Case 4: Both papules were removed by shave biopsy with good results. Histopathologicexamination revealed nevus cells confined to the dermis in nests orcords; 2

intradermal melanocytic nevi

were diagnosed.An intradermal nevus is a common melanocytic nevus. Most of these usuallydome-shaped, nodular, or polypoid lesions occur in adults. The nevi are oftenflesh-colored, or they can be slightly pigmented. Hairs may protrude throughthe surface. Very rarely, a melanoma may develop within an intradermal nevus;because of this potential, histopathologic examination of these nevi is prudent.

Case 5:

A large, well-defined, hypopigmentedmacule with an irregular border isnoted on the lower back of a 58-yearoldwoman; in addition, a few smallermacules appear beyond the border.The patient reports that the lesionhas been present since birth and hasnot changed.Do you recognize this lesion?

Case 5:

Nevus anemicus

is a rare congenital lesion that ismore common in women than in men. It is usually locatedon the chest or back. When the nevus is rubbed, a flaredoes not appear; however, a normal flare will occur outsidethe lesion. It is thought that the hypopigmentation is secondaryto relative vasoconstriction caused by increasedblood vessel sensitivity to catecholamines.Nevus anemicus is most frequently confused withtinea versicolor or vitiligo. Tinea macules generally featurescale; if the diagnosis is in doubt, a potassium hydroxidepreparation can rule out this fungal infection. A Woodlamp examination accentuates the depigmentation of themultiple spots of vitiligo, which characteristically involvethe hands, feet, and penis.

Case 6:

A 29-year-old woman presents for evaluationof a large blue-gray to brownpatch that surrounds her left eye andinvolves the sclera.What treatment will yourecommend?A

nevus of Ota

is a hamartoma of dermal melanocytes. The lesion may be present at birth,appear during the first few years of life, or arise in early adolescence. These nevi are more commonamong Asians and African Americans than among white persons. The male-to-female ratio is 4:1.A nevus of Ota presents as a unilateral blue-brown, speckled patch, usually involving the malarregion, periorbital area, temple, or forehead. The nevus may also affect the eye, as in this patient.Ocular muscles, periosteum, oral and buccal mucosae, and the retrobulbar fat may also be involved.These lesions enlarge slowly, become deeper in color, and persist throughout life. Approximately1 in 8 patients presents with bilateral patches rather than a unilateral lesion. Generally, neviof Ota are considered benign; however, rare cases of melanoma arising within the nevus have beenreported.

1,2

Histopathologically, the nevus of Ota is identical to the nevus of Ito; both demonstrate an increasednumber of elongated dendritic melanocytes scattered throughout the dermis. They differonly in their location; the nevus of Ito is commonly found in the supraclavicular area, side of theneck, shoulder, and scapular areas.The blue mongolian spot is similarto the nevus of Ota and the nevusof Ito. All 3 lesions represent a migrationor arrest of melanocytes duringembryologic development.The Nd:YAG laser has beenused successfully to lighten the neviof Ota and Ito, and mongolian spots.Because of the depth of the pigment,bleaching agents have little or noeffect. This patient plans to undergolaser treatment in the future.

References:

REFERENCE:


1. Friedman RJ, Rigel DS. The clinical features ofmalignant melanoma.

Dermatol Clin.

1985;3:271-283

FOR MORE INFORMATION:


  • Weedon D. Skin Pathology. 2nd ed. London: Churchill Livingstone; 2002:806-808.


REFERENCES:


1.

Ackerman AB, Kerl H, Sanchez J.

A Clinical Atlasof 101 Common Skin Diseases:

With HistopathologicCorrelation. New York: Ardor Scribendi; 2000.

2.

Dover JS, Jackson BA.

Pocket Guide to CutaneousMedicine and Surgery.

Philadelphia: WB Saunders Co;1996.