Patient Presentation
A 6-year-old Caucasian female presented to the pediatric dermatology clinic with numerous tan and pink verrucous papules coalescing into a heart-shaped 2.3-cm x 1.5-cm plaque on her left anterior thigh (Figure 1). Underlying the same region of her left anterior thigh, she had a 6.5-cm x 1.5-cm linear hypopigmented patch that followed the lines of Blaschko. Her mother reported that both lesions were asymptomatic, had been present since birth, and were enlarging in proportion to her general body growth. The patient’s medical history was unremarkable for any abnormalities.
What is Your Diagnosis?
Diagnosis: Epidermal Nevus with Underlying Nevus Depigmentosus
Epidermal nevi are benign hamartomatous lesions that often present at birth, but they may also develop later in life. They are likely the result of somatic mutations.1,2 Von Baerensprung first described an epidermal nevus in 1863, naming a variant, “naevus unius lateralis”.3 Nevus depigmentosus, also known as nevus achromicus, is a well-demarcated patch of hypopigmentation that tends to be round or oval and usually occurs on the trunk or proximal extremities. First described by Lesser in 1884, it is an uncommon, congenital, stable, sporadically occurring quasidermatomal hypomelanosis.4
In one case report by Adebola et al, the findings of nevus depigmentosus and inflammatory linear epidermal nevus were reported to co-occur on the same side of a patient’s body.5 As the co-occurrence of a heart-shaped epidermal nevus and a nevus depigmentosus localized to the left anterior thigh in our patient was somewhat unusual, further histopathological studies were pursued.
Pathogenesis
The pathogenesis of epidermal nevi is unclear; however, they arise from embryonic ectoderm that then differentiates into keratinocytes and the cells that form the epidermal appendages. Epidermal nevi are multicellular structures best categorized into their predominant cellular makeup, whether it is keratinocytic, sebaceous, follicular or sweat gland nevi. Each type of epidermal nevi represents the cutaneous manifestation of a unique mosaic phenotype.6-8 On the other hand, nevus depigmentosus is believed to result from the impaired transfer of melanosomes from melanocytes to keratinocytes, and the number of melanocytes are reported to be either normal or slightly reduced.9,10
Clinical Features
Epidermal nevi usually present on the extremities, affect both sexes equally, and are usually asymptomatic, although pruritus has been reported to occur in inflammatory linear verrucous epidermal nevi. Linear epidermal nevi frequently follow the lines of Blaschko. These lines are thought to represent examples of cutaneous mosaicism in embryologic development. Individual lesions may be hyperpigmented or skin-colored and have either a velvety or verrucous texture. There are many different types of epidermal nevi, which include verrucous (localized, congenital, warty papule or plaque), ichthyosis hystrix (“porcupine-like,” verrucous hyperkeratosis), systematized (extensive, bilateral, and often truncal), and nevus unius lateris (extensive unilateral lesions).1,2 When coupled with neurologic, ocular, skeletal, and cardiovascular abnormalities, the diagnosis of epidermal nevus syndrome (ENS) should be considered.11,12 Epidermal nevus syndrome or nevus sebaceous (also known as Solomon and/or Jadassohn syndrome) or Schimmelpenning-Feuerstein-Mims syndromes are sporadically arising genodermatoses. Multiple epidermal nevi can also be found in neurocutaneous congenital hemidysplasia with ichthyosiform nevus and limb defects (CHILD) syndrome. When skin involvement is extensive in patients with ENS, the defective gene may be transmitted to future children, resulting in a more widespread ichthyosiform condition known as epidermolytic hyperkeratosis.6
A single nevus depigmentosus occurs in approximately 0.2% to 0.3% of all neonates.6 Linear lesions, which often cover large body surfaces, may at times resemble splashed paint.13,14 Nevus depigmentosus is a congenital pigmentary process categorized as a single isolated circular-rectangular lesion, segmental lesion, or systematized lesion. The systematized variant usually follows the lines of Blaschko.15 Although there is no sex predilection or definitive pattern of inheritance, the lesions persist throughout an individual’s life.
Although patients with nevus depigmentosus are otherwise healthy, associated neurological defects have been reported.16 One rare case described nevus depigmentosus associated with developmental delay and seizure disorder.17 Yet in a large series study of 4,641 newborns, neurological defects were not found to be closely associated.13 In an analysis of 20 patients with segmental nevus depigmentosus, two patients were found to have pes cavus, hemihypertrophy, mental retardation, and seizure disorder.18 The diagnosis of both epidermal nevi and nevus depigmentosus are usually made clinically; biopsy is required only for confirmation.
Histology
Histologically, a variety of features have been described for epidermal nevi; however, those that reveal “epidermolytic hyperkeratosis” imply a mosaic disorder of keratin genes. In addition, acanthosis, papillomatosis, and increased melanin in the basal layer have been described.
Although the skin appears normal, upon histological examination of nevus depigmentosus, electron microscopic examination demonstrates a defect in transfer of pigment between melanocytes and keratinocytes, which produces the hypopigmentation.9
Our patient’s biopsy revealed papillomatosus, slight hyperkeratosis, focal epidermal thickening, and basal hypermelanosis.
Differential Diagnosis
The differential diagnosis of an epidermal nevus includes linear whorled hypermelanosis (presenting as whorled pigment following Blaschko’s lines), lichen striatus (acquired erythematous-to-skin-colored lichenoid papules coalescing into linear plaques following Blaschko’s lines, which commonly affect the lower leg and tend to regress with time), incontinentia pigmenti (verrucous stage, changes with time), hypomelanosis of Ito (the negative image of the hyperpigmented stage of incontinentia pigmenti and generally associated with neurological and skeletal malformations), or an inflammatory linear verrucous epidermal nevus (pruritic, erythematous, linearly arranged papules and plaques with a more chronic course).
The differential diagnosis of nevus depigmentosus includes vitiligo, hypomelanotic macules of tuberous sclerosis, and nevus anemicus.
Vitiligo can be differentiated from nevus depigmentosus by a bright white appearance under Wood’s lamp examination.
In a patient with tuberous sclerosis, other skin findings would be present, such as adenoma sebaceum, angiofibromas, Shagreen patch favoring the buttock area, periungual fibromas, fibrous plaques, or hamartomas of the skin favoring the forehead.
Nevus anemicus is a developmental anomaly described as a round-to-oval patch of pale or mottled skin.19,20 Friction or heat application fails to induce erythema of the hypomelanotic areas, and the lesion disappears with blanching. Also within the differential diagnosis is hypomelanosis of Ito (incontinentia pigmenti achromians), which is associated with congenital abnormalities involving multiple organ systems and presents as hypopigmented bands and whorls following Blaschko’s lines. Likewise, the fourth stage of incontinentia pigmenti should be ruled out. Patients with incontinentia pigmenti also have hypopigmented but atrophic lesions found primarily on the lower limbs. A positive history of changes to the index lesion including vesicular, verrucous, and hyperpigmentation should be elicited.
Treatment
Treatment for epidermal nevi can be challenging. Potential therapies include topical and intralesional steroids, topical and systemic retinoids, topical calcitriol, podyphillin, topical 5-fluorouracil, dermabrasion, liquid nitrogen cryotherapy, CO2 laser therapy, and surgical excision.1,21-23 Surgical excision provides the best opportunity for complete remission but is limited by scar formation. For the pruritus associated with epidermal nevi, the flashlamp pumped pulsed-dye laser has been reported to be effective.24
Treatment of nevus depigmentosus is not necessary and was not sought by our patient. Cover-up makeup is another option for cosmesis. In addition, without a tan, the lesion is less noticeable. Regardless, broad-spectrum sunscreen and sun avoidance is strongly recommended to diminish the cosmetic appearance of the lesion as well as to prevent painful sunburn.
Our patient’s treatment included topical tazarotene 0.1% cream (Avage) nightly to the epidermal nevus to give the nevus a smoother and flatter appearance. She was also instructed to avoid sun exposure during peak sun hours and to regularly wear sunscreen.
CALL FOR CASES
If you have a case you’d like to see published, send a write-up (1,200 to 1,500 words) and an image of the patient’s condition to:
Dr. Amor Khachemoune
Ronald O. Perelman
Department of Dermatology
New York University School of Medicine
530 First Avenue, Ste. 7R
New York, NY 10016
Or, e-mail them to amorkh@pol.net.
Patient Presentation
A 6-year-old Caucasian female presented to the pediatric dermatology clinic with numerous tan and pink verrucous papules coalescing into a heart-shaped 2.3-cm x 1.5-cm plaque on her left anterior thigh (Figure 1). Underlying the same region of her left anterior thigh, she had a 6.5-cm x 1.5-cm linear hypopigmented patch that followed the lines of Blaschko. Her mother reported that both lesions were asymptomatic, had been present since birth, and were enlarging in proportion to her general body growth. The patient’s medical history was unremarkable for any abnormalities.
What is Your Diagnosis?
Diagnosis: Epidermal Nevus with Underlying Nevus Depigmentosus
Epidermal nevi are benign hamartomatous lesions that often present at birth, but they may also develop later in life. They are likely the result of somatic mutations.1,2 Von Baerensprung first described an epidermal nevus in 1863, naming a variant, “naevus unius lateralis”.3 Nevus depigmentosus, also known as nevus achromicus, is a well-demarcated patch of hypopigmentation that tends to be round or oval and usually occurs on the trunk or proximal extremities. First described by Lesser in 1884, it is an uncommon, congenital, stable, sporadically occurring quasidermatomal hypomelanosis.4
In one case report by Adebola et al, the findings of nevus depigmentosus and inflammatory linear epidermal nevus were reported to co-occur on the same side of a patient’s body.5 As the co-occurrence of a heart-shaped epidermal nevus and a nevus depigmentosus localized to the left anterior thigh in our patient was somewhat unusual, further histopathological studies were pursued.
Pathogenesis
The pathogenesis of epidermal nevi is unclear; however, they arise from embryonic ectoderm that then differentiates into keratinocytes and the cells that form the epidermal appendages. Epidermal nevi are multicellular structures best categorized into their predominant cellular makeup, whether it is keratinocytic, sebaceous, follicular or sweat gland nevi. Each type of epidermal nevi represents the cutaneous manifestation of a unique mosaic phenotype.6-8 On the other hand, nevus depigmentosus is believed to result from the impaired transfer of melanosomes from melanocytes to keratinocytes, and the number of melanocytes are reported to be either normal or slightly reduced.9,10
Clinical Features
Epidermal nevi usually present on the extremities, affect both sexes equally, and are usually asymptomatic, although pruritus has been reported to occur in inflammatory linear verrucous epidermal nevi. Linear epidermal nevi frequently follow the lines of Blaschko. These lines are thought to represent examples of cutaneous mosaicism in embryologic development. Individual lesions may be hyperpigmented or skin-colored and have either a velvety or verrucous texture. There are many different types of epidermal nevi, which include verrucous (localized, congenital, warty papule or plaque), ichthyosis hystrix (“porcupine-like,” verrucous hyperkeratosis), systematized (extensive, bilateral, and often truncal), and nevus unius lateris (extensive unilateral lesions).1,2 When coupled with neurologic, ocular, skeletal, and cardiovascular abnormalities, the diagnosis of epidermal nevus syndrome (ENS) should be considered.11,12 Epidermal nevus syndrome or nevus sebaceous (also known as Solomon and/or Jadassohn syndrome) or Schimmelpenning-Feuerstein-Mims syndromes are sporadically arising genodermatoses. Multiple epidermal nevi can also be found in neurocutaneous congenital hemidysplasia with ichthyosiform nevus and limb defects (CHILD) syndrome. When skin involvement is extensive in patients with ENS, the defective gene may be transmitted to future children, resulting in a more widespread ichthyosiform condition known as epidermolytic hyperkeratosis.6
A single nevus depigmentosus occurs in approximately 0.2% to 0.3% of all neonates.6 Linear lesions, which often cover large body surfaces, may at times resemble splashed paint.13,14 Nevus depigmentosus is a congenital pigmentary process categorized as a single isolated circular-rectangular lesion, segmental lesion, or systematized lesion. The systematized variant usually follows the lines of Blaschko.15 Although there is no sex predilection or definitive pattern of inheritance, the lesions persist throughout an individual’s life.
Although patients with nevus depigmentosus are otherwise healthy, associated neurological defects have been reported.16 One rare case described nevus depigmentosus associated with developmental delay and seizure disorder.17 Yet in a large series study of 4,641 newborns, neurological defects were not found to be closely associated.13 In an analysis of 20 patients with segmental nevus depigmentosus, two patients were found to have pes cavus, hemihypertrophy, mental retardation, and seizure disorder.18 The diagnosis of both epidermal nevi and nevus depigmentosus are usually made clinically; biopsy is required only for confirmation.
Histology
Histologically, a variety of features have been described for epidermal nevi; however, those that reveal “epidermolytic hyperkeratosis” imply a mosaic disorder of keratin genes. In addition, acanthosis, papillomatosis, and increased melanin in the basal layer have been described.
Although the skin appears normal, upon histological examination of nevus depigmentosus, electron microscopic examination demonstrates a defect in transfer of pigment between melanocytes and keratinocytes, which produces the hypopigmentation.9
Our patient’s biopsy revealed papillomatosus, slight hyperkeratosis, focal epidermal thickening, and basal hypermelanosis.
Differential Diagnosis
The differential diagnosis of an epidermal nevus includes linear whorled hypermelanosis (presenting as whorled pigment following Blaschko’s lines), lichen striatus (acquired erythematous-to-skin-colored lichenoid papules coalescing into linear plaques following Blaschko’s lines, which commonly affect the lower leg and tend to regress with time), incontinentia pigmenti (verrucous stage, changes with time), hypomelanosis of Ito (the negative image of the hyperpigmented stage of incontinentia pigmenti and generally associated with neurological and skeletal malformations), or an inflammatory linear verrucous epidermal nevus (pruritic, erythematous, linearly arranged papules and plaques with a more chronic course).
The differential diagnosis of nevus depigmentosus includes vitiligo, hypomelanotic macules of tuberous sclerosis, and nevus anemicus.
Vitiligo can be differentiated from nevus depigmentosus by a bright white appearance under Wood’s lamp examination.
In a patient with tuberous sclerosis, other skin findings would be present, such as adenoma sebaceum, angiofibromas, Shagreen patch favoring the buttock area, periungual fibromas, fibrous plaques, or hamartomas of the skin favoring the forehead.
Nevus anemicus is a developmental anomaly described as a round-to-oval patch of pale or mottled skin.19,20 Friction or heat application fails to induce erythema of the hypomelanotic areas, and the lesion disappears with blanching. Also within the differential diagnosis is hypomelanosis of Ito (incontinentia pigmenti achromians), which is associated with congenital abnormalities involving multiple organ systems and presents as hypopigmented bands and whorls following Blaschko’s lines. Likewise, the fourth stage of incontinentia pigmenti should be ruled out. Patients with incontinentia pigmenti also have hypopigmented but atrophic lesions found primarily on the lower limbs. A positive history of changes to the index lesion including vesicular, verrucous, and hyperpigmentation should be elicited.
Treatment
Treatment for epidermal nevi can be challenging. Potential therapies include topical and intralesional steroids, topical and systemic retinoids, topical calcitriol, podyphillin, topical 5-fluorouracil, dermabrasion, liquid nitrogen cryotherapy, CO2 laser therapy, and surgical excision.1,21-23 Surgical excision provides the best opportunity for complete remission but is limited by scar formation. For the pruritus associated with epidermal nevi, the flashlamp pumped pulsed-dye laser has been reported to be effective.24
Treatment of nevus depigmentosus is not necessary and was not sought by our patient. Cover-up makeup is another option for cosmesis. In addition, without a tan, the lesion is less noticeable. Regardless, broad-spectrum sunscreen and sun avoidance is strongly recommended to diminish the cosmetic appearance of the lesion as well as to prevent painful sunburn.
Our patient’s treatment included topical tazarotene 0.1% cream (Avage) nightly to the epidermal nevus to give the nevus a smoother and flatter appearance. She was also instructed to avoid sun exposure during peak sun hours and to regularly wear sunscreen.
CALL FOR CASES
If you have a case you’d like to see published, send a write-up (1,200 to 1,500 words) and an image of the patient’s condition to:
Dr. Amor Khachemoune
Ronald O. Perelman
Department of Dermatology
New York University School of Medicine
530 First Avenue, Ste. 7R
New York, NY 10016
Or, e-mail them to amorkh@pol.net.
Patient Presentation
A 6-year-old Caucasian female presented to the pediatric dermatology clinic with numerous tan and pink verrucous papules coalescing into a heart-shaped 2.3-cm x 1.5-cm plaque on her left anterior thigh (Figure 1). Underlying the same region of her left anterior thigh, she had a 6.5-cm x 1.5-cm linear hypopigmented patch that followed the lines of Blaschko. Her mother reported that both lesions were asymptomatic, had been present since birth, and were enlarging in proportion to her general body growth. The patient’s medical history was unremarkable for any abnormalities.
What is Your Diagnosis?
Diagnosis: Epidermal Nevus with Underlying Nevus Depigmentosus
Epidermal nevi are benign hamartomatous lesions that often present at birth, but they may also develop later in life. They are likely the result of somatic mutations.1,2 Von Baerensprung first described an epidermal nevus in 1863, naming a variant, “naevus unius lateralis”.3 Nevus depigmentosus, also known as nevus achromicus, is a well-demarcated patch of hypopigmentation that tends to be round or oval and usually occurs on the trunk or proximal extremities. First described by Lesser in 1884, it is an uncommon, congenital, stable, sporadically occurring quasidermatomal hypomelanosis.4
In one case report by Adebola et al, the findings of nevus depigmentosus and inflammatory linear epidermal nevus were reported to co-occur on the same side of a patient’s body.5 As the co-occurrence of a heart-shaped epidermal nevus and a nevus depigmentosus localized to the left anterior thigh in our patient was somewhat unusual, further histopathological studies were pursued.
Pathogenesis
The pathogenesis of epidermal nevi is unclear; however, they arise from embryonic ectoderm that then differentiates into keratinocytes and the cells that form the epidermal appendages. Epidermal nevi are multicellular structures best categorized into their predominant cellular makeup, whether it is keratinocytic, sebaceous, follicular or sweat gland nevi. Each type of epidermal nevi represents the cutaneous manifestation of a unique mosaic phenotype.6-8 On the other hand, nevus depigmentosus is believed to result from the impaired transfer of melanosomes from melanocytes to keratinocytes, and the number of melanocytes are reported to be either normal or slightly reduced.9,10
Clinical Features
Epidermal nevi usually present on the extremities, affect both sexes equally, and are usually asymptomatic, although pruritus has been reported to occur in inflammatory linear verrucous epidermal nevi. Linear epidermal nevi frequently follow the lines of Blaschko. These lines are thought to represent examples of cutaneous mosaicism in embryologic development. Individual lesions may be hyperpigmented or skin-colored and have either a velvety or verrucous texture. There are many different types of epidermal nevi, which include verrucous (localized, congenital, warty papule or plaque), ichthyosis hystrix (“porcupine-like,” verrucous hyperkeratosis), systematized (extensive, bilateral, and often truncal), and nevus unius lateris (extensive unilateral lesions).1,2 When coupled with neurologic, ocular, skeletal, and cardiovascular abnormalities, the diagnosis of epidermal nevus syndrome (ENS) should be considered.11,12 Epidermal nevus syndrome or nevus sebaceous (also known as Solomon and/or Jadassohn syndrome) or Schimmelpenning-Feuerstein-Mims syndromes are sporadically arising genodermatoses. Multiple epidermal nevi can also be found in neurocutaneous congenital hemidysplasia with ichthyosiform nevus and limb defects (CHILD) syndrome. When skin involvement is extensive in patients with ENS, the defective gene may be transmitted to future children, resulting in a more widespread ichthyosiform condition known as epidermolytic hyperkeratosis.6
A single nevus depigmentosus occurs in approximately 0.2% to 0.3% of all neonates.6 Linear lesions, which often cover large body surfaces, may at times resemble splashed paint.13,14 Nevus depigmentosus is a congenital pigmentary process categorized as a single isolated circular-rectangular lesion, segmental lesion, or systematized lesion. The systematized variant usually follows the lines of Blaschko.15 Although there is no sex predilection or definitive pattern of inheritance, the lesions persist throughout an individual’s life.
Although patients with nevus depigmentosus are otherwise healthy, associated neurological defects have been reported.16 One rare case described nevus depigmentosus associated with developmental delay and seizure disorder.17 Yet in a large series study of 4,641 newborns, neurological defects were not found to be closely associated.13 In an analysis of 20 patients with segmental nevus depigmentosus, two patients were found to have pes cavus, hemihypertrophy, mental retardation, and seizure disorder.18 The diagnosis of both epidermal nevi and nevus depigmentosus are usually made clinically; biopsy is required only for confirmation.
Histology
Histologically, a variety of features have been described for epidermal nevi; however, those that reveal “epidermolytic hyperkeratosis” imply a mosaic disorder of keratin genes. In addition, acanthosis, papillomatosis, and increased melanin in the basal layer have been described.
Although the skin appears normal, upon histological examination of nevus depigmentosus, electron microscopic examination demonstrates a defect in transfer of pigment between melanocytes and keratinocytes, which produces the hypopigmentation.9
Our patient’s biopsy revealed papillomatosus, slight hyperkeratosis, focal epidermal thickening, and basal hypermelanosis.
Differential Diagnosis
The differential diagnosis of an epidermal nevus includes linear whorled hypermelanosis (presenting as whorled pigment following Blaschko’s lines), lichen striatus (acquired erythematous-to-skin-colored lichenoid papules coalescing into linear plaques following Blaschko’s lines, which commonly affect the lower leg and tend to regress with time), incontinentia pigmenti (verrucous stage, changes with time), hypomelanosis of Ito (the negative image of the hyperpigmented stage of incontinentia pigmenti and generally associated with neurological and skeletal malformations), or an inflammatory linear verrucous epidermal nevus (pruritic, erythematous, linearly arranged papules and plaques with a more chronic course).
The differential diagnosis of nevus depigmentosus includes vitiligo, hypomelanotic macules of tuberous sclerosis, and nevus anemicus.
Vitiligo can be differentiated from nevus depigmentosus by a bright white appearance under Wood’s lamp examination.
In a patient with tuberous sclerosis, other skin findings would be present, such as adenoma sebaceum, angiofibromas, Shagreen patch favoring the buttock area, periungual fibromas, fibrous plaques, or hamartomas of the skin favoring the forehead.
Nevus anemicus is a developmental anomaly described as a round-to-oval patch of pale or mottled skin.19,20 Friction or heat application fails to induce erythema of the hypomelanotic areas, and the lesion disappears with blanching. Also within the differential diagnosis is hypomelanosis of Ito (incontinentia pigmenti achromians), which is associated with congenital abnormalities involving multiple organ systems and presents as hypopigmented bands and whorls following Blaschko’s lines. Likewise, the fourth stage of incontinentia pigmenti should be ruled out. Patients with incontinentia pigmenti also have hypopigmented but atrophic lesions found primarily on the lower limbs. A positive history of changes to the index lesion including vesicular, verrucous, and hyperpigmentation should be elicited.
Treatment
Treatment for epidermal nevi can be challenging. Potential therapies include topical and intralesional steroids, topical and systemic retinoids, topical calcitriol, podyphillin, topical 5-fluorouracil, dermabrasion, liquid nitrogen cryotherapy, CO2 laser therapy, and surgical excision.1,21-23 Surgical excision provides the best opportunity for complete remission but is limited by scar formation. For the pruritus associated with epidermal nevi, the flashlamp pumped pulsed-dye laser has been reported to be effective.24
Treatment of nevus depigmentosus is not necessary and was not sought by our patient. Cover-up makeup is another option for cosmesis. In addition, without a tan, the lesion is less noticeable. Regardless, broad-spectrum sunscreen and sun avoidance is strongly recommended to diminish the cosmetic appearance of the lesion as well as to prevent painful sunburn.
Our patient’s treatment included topical tazarotene 0.1% cream (Avage) nightly to the epidermal nevus to give the nevus a smoother and flatter appearance. She was also instructed to avoid sun exposure during peak sun hours and to regularly wear sunscreen.
CALL FOR CASES
If you have a case you’d like to see published, send a write-up (1,200 to 1,500 words) and an image of the patient’s condition to:
Dr. Amor Khachemoune
Ronald O. Perelman
Department of Dermatology
New York University School of Medicine
530 First Avenue, Ste. 7R
New York, NY 10016
Or, e-mail them to amorkh@pol.net.
