History
Small keratotic papules typically begin to develop symmetrically on the lower extremities (see the images below).
Clinical photograph of the upper thigh showing numerous red-brown papules with sparing of the inguinal crease.
A higher-powered view of the patient seen in the previous image. Photograph of the upper thigh demonstrates 1- to 4-mm, noncoalescing keratotic papules.
Papules spread proximally at a slow rate. Hyperkeratosis lenticularis perstans usually is an asymptomatic condition.
Physical Examination
Small, red-brown, hyperkeratotic, 1-5 mm papules on the lower extremities are the most frequent and characteristic presentation of hyperkeratosis lenticularis perstans. [4, 5] Involvement of the eyes, ear pinnae, arms, axillae, palms, soles, and the oral mucosa has been reported, although these reports are rare. Involvement of the trunk has been reported but remains an unusual variant. [6, 7, 8]
Dermatoscopic findings suggest a brown, structureless center with peripheral scaly, white areas enhanced by polarized light. [9]
Removal of the scale reveals a bright-red base, often with pinpoint bleeding. A localized unilateral variant has been reported. [10, 11] The trunk tends to be spared; absence of axial lesions is characteristic.
Causes
To date, the causes of hyperkeratosis lenticularis perstans (Flegel disease) are unknown. Some authors suggest that exposure to the sun may be involved.
-
Clinical photograph of the upper thigh showing numerous red-brown papules with sparing of the inguinal crease.
-
A higher-powered view of the patient seen in the previous image. Photograph of the upper thigh demonstrates 1- to 4-mm, noncoalescing keratotic papules.
-
Hematoxylin and eosin-stained section, low magnification. Epidermal hyperplasia with rete elongation surmounted by a thickened, compact, hyperkeratotic scale. A bandlike lymphoid infiltrate expands the papillary dermis.
-
Hematoxylin and eosin-stained section, medium magnification. The lateral edge of the lesion demonstrates abrupt hyperkeratosis and a combination of epidermal atrophy and acanthosis.
-
Hematoxylin and eosin-stained section, high magnification. The section shows mostly orthokeratotic scale, thinning of the epidermis with a diminished granular cell layer, and an infiltrate of lymphocytes in the superficial dermis, which approximate the dermal-epidermal interface.
