Disseminated hypopigmented keratosis is a distinct clinical entity and only few cases have been reported so far. Here, we present a 21-year-old man with almost 10-year history of hypopigmented, nonfollicular, keratotic lichenoid papules occurring on the extensor surfaces of the extremities, back and lumber region. Histopathological examination showed orthohyperkeratosis, irregular acanthosis, and sporadic papillomatosis with a normal amount of melanin and number of melanocytes. In addition, no marked inflammation or melanophages were seen. In order to exclude other possible causes, we performed laboratory tests and radiological examination which were all found to be normal. As the clinical and histopathological features of our patient were taken into account, it was considered to be compatible with the diagnosis of disseminated hypopigmented keratoses. So far, only topical therapies have been used with failure in the previously reported cases except one patient. Considering the extensive lesions, we treated the present patient with 5% salicylic acid in addition to oral acitretin and significant regression in all lesions was achieved, particularly on the keratosis.
Disseminated hypopigmented keratosis (DHK) was first described by Morison et al. in 1991 [
A 21-year-old man referred to our outpatient clinic because of the numerous asymptomatic hypopigmented lesions which appeared 10 years ago. The lesions persisted since the beginning and they had a course of gradual and slow increase in number. The lesions were disseminated during this period. He had no history of any systemic disease or phototherapy/UV exposure and he was healthy in all other respects. The family history was unremarkable.
Dermatological examination revealed hypopigmented, 2–5 mm in size, nonfollicular, numerous keratotic lichenoid papules on the whole body with a symmetrical distribution (Figure
(a) The hypopigmented keratotic lesions on the upper back. (b) The close-up appearance of the lesions on the extensor surface of the right upper arm.
Orthohyperkeratosis, irregular acanthosis, and sporadic papillomatosis. HE ×40 (HE: hematoxylin and eosin).
The patient was treated with topical 5% salicylic acid in petrolatum for 2 weeks and oral acitretin for 2 months and showed significant improvement predominantly on the keratosis (Figure
The appearance of the left upper back and the left upper arm after 2 months of the treatment.
Here we presented a case of DHK improved with oral acitretin that represents a distinct entity with a unique presentation [
The general characteristics of the cases of DHK reported in the literature.
Year | Author (ref.) | Age | Gender | Site | Age of onset | Histopathology |
---|---|---|---|---|---|---|
1991 | Morison et al. [ |
19 | Female | Trunk, extremities, and dorsa of the hands and feet | 19 | Mild orthohyperkeratosis and papillomatosis |
1991 | Morison et al. [ |
5 | Female | Extremities and trunk | 5 | Biopsy was not performed |
2013 | Kim et al. [ |
4 | Female | Arm, leg, and trunk | 2 | Hyperkeratosis, acanthosis, decreased melanin content, and number of melanocytes |
2013 | Kim et al. [ |
5 | Female | Arm | 0 | Same with above |
2013 | Kim et al. [ |
40 | Male | Trunk | 33 | Biopsy was not performed |
2013 | Kim et al. [ |
70 | Female | Trunk | 50 | Biopsy was not performed |
2017 | Present case | 21 | Male | Trunk, extremities, and face | 11 | Orthohyperkeratosis, irregular acanthosis, and sporadic papillomatosis |
In the study reported by Kim et al., 13 cases of HK were reported and 4 of them had a disseminated distribution [
Many dermatoses could be considered in the differential diagnosis of DHK including stucco keratosis, verruca plana, lichen nitidus, Darier’s disease, and guttate psoriasis. The diagnosis of DHK was established based on the exclusion of the differential diagnosis regarding the clinical and histological features.
A few treatment modalities were tried for the HK in the previous reports including tretinoin, propylene glycol, salicylic acid gel, and cryosurgery without significant improvement [
DHK is a rarely reported entity with widespread hypopigmented keratotic papules with unknown etiology. Acitretin may be a considerable option for the treatment of HK.
There are no conflicts of interest.