A case of reticulate acropigmentation of kitamura: dowling degos disease overlap with unusual clinical manifestations.

Reticulate hyperpigmentary disorders are a group of rare genetic pigmentary abnormalities which includes reticulate acropigmentation of Kitamura (RAPK), Dowling-Degos disease (DD), reticulate acropigmentation of Dohi (RAPD), Haber's syndrome, and Galli-Galli disease. A 25-year-old male presented with asymptomatic dark-colored lesions on his hands and feet with light-colored skin lesions involving the trunk since three years. Dermatological examination revealed hyperpigmented macules in a reticulate pattern involving the dorsa of the hands and feet, front and sides of the neck, axillae, periorbital region, and groin. Multiple pits were present over both palms, with breaks in dermatoglyphics. He also had multiple nonacne facial scars predominantly on the nose and malar areas. The patient had overlapping features of RAPK and DDD. In addition, he also had hypopigmented macules and acneiform facial scars. Such an overlap of features of reticulate pigmentation has not been previously reported in the literature.

What was known?

Reticulate hyperpigmentary disorders are a group of rare genetic pigmentary abnormalities which includes reticulate acropigmentation of Kitamura (RAPK), Dowling Degos disease (DD), reticulate acropigmentation of Dohi (RAPD), Haber's syndrome, and Galli-Galli disease.

A few reports on the coexistence of RAPK and DDD have been reported in the literature.

There is one previous report of an overlap of RAPK, RAPD, and DDD.

Introduction

Reticulate hyperpigmentary disorders are a group of rare genetic pigmentary abnormalities which are inherited in an autosomal dominant fashion. It includes reticulate acropigmentation of Kitamura (RAPK), Dowling Dego's disease (DDD), reticulate acropigmentation of Dohi (RAPD), Haber's syndrome, and Galli-Galli disease (GGD).[1] We herein present a case with overlap features of RAPK and DDD along with hypopigmented lesions, acneform facial scars, and unusual sites of reticulate hyperpigmentation. Such a manifestation has not been reported earlier in the literature.

Case Report

A 25-year-old male presented to us with asymptomatic dark-colored lesions on his hands and feet and light-colored skin lesions involving the trunk since three years. The dark-colored lesions increased progressively in number to involve other parts of his body. There was no history of similar complaints in the family and he was not a product of consanguinity.

Dermatological examination revealed mildly atrophic, hyperpigmented macules in a reticulate pattern involving the dorsa of the hands and feet [Figure 1a and b], front and sides of neck, and axillae [Figure 1c and d]. In addition, he had similar lesions on the periorbital region [Figure 2a], groin, and scrotum [Figure 2b]. He also had multiple hypopigmented macules widely distributed over the trunk and anterior aspect of both legs [Figure 2c]. Multiple pits were present over both palms, with breaks in dermatoglyphics. He also had multiple nonacne facial scars predominantly on the nose and malar areas [Figure 2d].

Figure 1

Reticulate hyperpigmentation on: (a) Dorsa of both hands (b) Dorsa of both feet (c) Neck (d) Axilla

Figure 2

Unusual features: (a) Reticulate hyperpigmentation in periorbital area (b) Reticulate hyperpigmentation on scrotum (c) Hypopigmented macules on trunk (d) Acneiform scars on nose

Skin biopsy from a hyperpigmented lesion on the dorsum of the hand revealed filiform elongation of rete ridges with hyperpigmentation of basilar keratinocytes and clusters of melanocytes at the tip of the rete ridges. Histopathology axillary lesion was also similar except for features of follicular plugging [Figure 3a and b]. Melan-A stain confirmed increased melanocytes [Figure 3c]; skin biopsy from hypopigmented lesion on left leg revealed decreased melanocytes [Figure 3d].

Figure 3

Histopathology of skin lesions: (a) Biopsy from axillary lesion demonstrating filiform elongation of the rete ridges, hyperpigmentation of basilar keratinocytes, and clusters of melanocytes at the tip of the rete ridges along with follicular plugging (H and E, ×10) (b) High-power view of the same (H and E, ×40) (c) Melan-A staining demonstrating the increased melanocytes (×40) (d) Biopsy from hypopigmented macules showing reduced number of melanocytes (H and E, ×40)

Discussion

RAPK was first described in Japan in 1943 by Kitamura and Akamatsu. About 100 cases have been reported so far, mostly in the Asian ethnic groups. It usually develops during the first and second decades of life. A network of freckle like pigmentation on the dorsa of hands and feet, palmoplantar pits, and break in dermatoglyphics are present. The pigmentary lesions slowly darken over time and sunlight may aggravate the condition. Histopathological examination shows epidermal atrophy associated with clublike elongation of rete ridges and clumps of melanocytes in the basal layer.

DDD was first described by Dowling in 1938 and Degos in 1954. It is characterized by reticular hyperpigmentation of flexor areas mainly the neck, axilla, antecubital fossa, submammary area, and groin.[2] Dark comedo-like lesions on the face and neck and pitted perioral acneiform scars maybe present. Onset can occur from adolescence to late adult life. Histopathology is similar to RAPK with prominent involvement of hair follicles.[3]

Acropigmentation of Dohi also has reticulate hyperpigmentation on dorsal extremities along with hypopigmented macules. Autosomal recessive inheritance may occur rarely.[4] The differentiation between RAD and RAPK is based on clinical and histological findings. In RAPK, there are usually no hypopigmented macules and histologically there is epidermal atrophy and increase in the number of basal melanocytes.

GGD was first described in 1982 in two brothers manifesting with hyperpigmented macules on the face and neck similar to DDD. However, histopathologically they showed acantholysis in the suprabasal epidermal layers and so were easily differentiated on performing a skin biopsy.

Haber's syndrome is usually characterized by verrucous papules on the trunk and acneiform facial scars.

Our patient had acral pigmentation and palmar pits resembling RAPK with flexural involvement resembling DDD. There have been many reports on the coexistence of RAPK and DDD in the literature.[56] Therefore, some authors suggest that RAPK and DDD are different ends of the spectrum of the same disease. In 1986, Crovato reported a family in which the clinical features of DDD were associated with those of RAPK.[7]

There is one previous report of an overlap of RAPK, RAPD, and DDD.[8] Our patient had reticulate hyperpigmentation of the dorsa of hands and feet along with extensive hypopigmented macules distributed over the trunk and limbs. Hypopigmented macules have rarely ever been described in RAPK and DDD. So, our patient could have a minor overlap of features suggestive of RAPD. He also had acneiform scars with no preceding acne. Perioral scars have been reported in DDD, but not nasal or malar area scars. So, our patient could be having features of Haber's disease which characteristically has acneiform facial scars. This further brings us to the surmise that all these entities may be a part of the same disease.

Most treatment attempts for these disorders have been unsatisfactory. Adapalene, systemic retinoids, and Q-switch alexandrite laser have been tried in a few patients with mixed results.[910] 20% azelaic acid has shown some benefit among these patients. We therefore had a patient with overlap features of RAPK and DDD which itself is rarely mentioned in the literature. In addition, he also had features of extensive hypopigmented macules and acneiform facial scars. Such an overlap of features has rarely been previously reported in the literature.

What is new?

In addition to features of an overlap of RAPK and DDD, our patient also had hypopigmented macules and acneiform scars with no preceding acne. This combination of features has rarely been reported in the literature.

All the reticulate hyperpigmentary disorders maybe a part of the same disease entity.