Localized hypopigmented keratoses

Abstract

A 16‐year‐old girl presented with a 2‐year history of hypopigmented, hard papules involving the extensor surfaces of the forearms and lower legs. Initially, 2–3‐mm‐sized papules were present on the forearms; gradually they increased in number and spread to involve the lower legs. Her family history was unremarkable. There was a history of worsening in the summer. On examination, she was skin type 3, with multiple, round, hypopigmented, keratotic, flat‐topped papules located on the distal dorsal parts of the extremities, with a stuck‐on appearance (Fig. 1). The papules were unrelated to follicular orifices, symmetrically distributed, and could not be detached. The lesions were not itchy. Her face, trunk, palms, and soles were spared, and no mucosal lesions were present. The nails and hair were normal. 1 Numerous, hypopigmented, flat‐topped papules on the arm Histologic examination of a papule revealed orthokeratotic hyperkeratosis, mild acanthosis, mild papillomatosis, and vacuolization in basal cells. A mild lymphocytic inflammatory response was seen. There were normal amounts of melanin in the basal cell layer and no melanophages were present (Fig. 2). 2 Hyperorthokeratosis, mild acanthosis, and papillomatosis. A mild inflammatory infiltrate is present in the dermis (hematoxylin and eosin, × 100) Despite some slight differences, the clinical and histologic features appeared to be similar to cases previously described under the title “disseminated hypopigmented keratoses”. The patient was treated with 0.1% tretinoin gel and 10% salicylic acid ointment and marked improvement was observed after several weeks.

Hypopigmented keratosis: is it a hyperkeratotic variant of idiopathic guttate hypomelanosis?

“…We identified two similar cases in the literature, which had been diagnosed as disseminated and localized hypopigmented keratosis. 1,2 The clinical appearance in those cases was of multiple, hypopigmented, keratotic, flat-topped papules, similar to our patient samples. Histopathologically, the previous cases also had marked hyperkeratosis, which was consistent with our patient cases, but the former had the additional findings of mild acanthosis with papillomatosis and vacuolar alteration of the basal layer, which we did not see in our cases.…”

“…The lesions were well‐demarcated, hypopigmented papules, characterized by decreased melanogenesis and marked hyperkeratosis. We identified two similar cases in the literature, which had been diagnosed as disseminated and localized hypopigmented keratosis . The clinical appearance in those cases was of multiple, hypopigmented, keratotic, flat‐topped papules, similar to our patient samples.…”

“…Stucco keratoses are small, whitish, keratotic papules and plaques that may clinically resemble our patient samples; however, the papules and plaques of stucco keratoses are easily lifted off from the skin with a fingernail, are found in high numbers, are located principally on the limbs, and generally occur in older people. 2,5 The histopathological characteristics of stucco keratosis, such as a 'church spire'-like papillomatosis, make this condition distinguishable from the hyperkeratotic variant of IGH. 5 Some authors have suggested that stucco keratosis is one of the subtypes of seborrheic keratosis.…”

Annular hypopigmented mycosis fungoides: a novel ringed variant

“…This entity has been described in vitiligo patients treated with both PUVA and UV-B therapy. 21,22 The raised and keratotic nature is in stark contrast to the macular hypopigmented lesions observed in our patient. Disseminated annular lichen planus and porokeratosis could also be considered in the clinical scenario; however, the histopathologic findings did not support either of these conditions.…”

Confetti-like lesions with hyperkeratosis: a novel ultraviolet-induced hypomelanotic disorder?

“…Accordingly, stucco keratosis, lichen sclerosus et atrophicus and verrucae planae juveniles may be confused, especially in their early stage, with confetti leucoderma. Another ‘confetti‐like’ dermatosis is disseminated hypopigmented keratoses, an extremely rare entity that has been reported only twice in the dermatological literature 2,3 . We report a unique constellation of dermatopathological, immunohistochemical and ultrastructural findings in a patient with vitiligo and mycosis fungoides following phototherapy.…”