Lichen Nitidus

Clinical Presentation:

■ Chronic eruption which typically presents as multiple, grouped, asymptomatic, pinpoint-sized, flesh-colored papules in children and young adult men

■ Occurs most commonly on the upper extremities and genitalia

Histology:

■ Lymphohistiocytic infiltrate filling the dermal papilla and obscuring the dermoepidermal junction (Fig. 12)

■ "Claw-like" hyperplasia of the rete surround the infiltrate (Fig. 12)

■ Epithelioid and multinucleated histiocytes may be present, or the infiltrate may be frankly granulomatous (Fig. 12)

Immunofluorescence:

■ Direct immunofluorescence is usually negative (in contrast to lichen planus)

Differential Diagnosis:

Lichen Nitidus

Lichen Scrofulosorum

Infiltrate causes widening of

Granulomatous infiltrate does not

dermal papillae

expand dermal papillae

Neutrophils not usually a

There may be neutrophils in the epider-

feature

mis associated with mild spongiosis

Pathophysiology:

■ The etiology of lichen nitidus is unknown

■ The relationship between lichen nitidus and lichen planus is controversial

References:

1. Lapins NA, Willoughby C, Helwig EB. Lichen nitidus. A study of forty-three cases. Cutis 1978; 21:634-637.

2. Smoller BR, Flynn TC. Immunohistochemical examination of lichen nitidus suggests that it is not a localized papular variant of lichen planus. J Am Acad Dermatol 1992; 27:232-236.

3. Khopkar U, Joshi R. Distinguishing lichen scrofulosorum from lichen nitidus. Dermatopathol: Practical Concept 1999; 5:44-45.

LICHENOID INTERFACE DERMATITIS—SUPERFICIAL AND DEEP

LICHEN STRIATUS Clinical Presentation:

■ Typically presents as a unilateral, pruritic eruption of Blaschko linearly-arranged, erythematous, slightly scaly papules in children or adolescents

■ There is a female predominance

■ Sites of predilection are the extremities, neck, and trunk; occasionally, there is nail involvement

Histology:

■ Superficial and deep perivascular and periadnexal (often peri-eccrine) inflammatory cell infiltrate (Fig. 13A)

■ Band-like lymphohistiocytic infiltrate which obscures the dermoepidermal junction (Fig. 13B)

Clinicopathologic Correlation:

Clinical Feature

Histopathologic Correlate

Purpuric papules

Extravasated erythrocytes in superficial dermis

Pigmented Purpuric Dermatosis

Mycosis Fungoides

Stasis Dermatitis

Hemosiderin

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