Phacomatosis pigmentokeratotica: speckled-lentiginous nevus in association with nevus sebaceus

Phacomatosis spilosebacea: A new name for a distinctive binary genodermatosis

Phacomatosis pigmentokeratotica (PPK) is defined by the association of papular nevus spilus arranged in a flag-like pattern and sebaceous nevus following Blaschko's lines. A systematic search of the worldwide literature retrieved 95 well-established PPK cases. An additional 30 cases were excluded for a number of reasons. Based on this study, we propose to rename PPK phacomatosis spilosebacea (PSS). Mosaic mutations of the HRAS gene are the only proven cause of PSS. The extracutaneous abnormalities of PSS result from various degrees of intermingling of Schimmelpenning syndrome and papular nevus spilus syndrome. PSS seems to be a condition at particularly high risk of developing basal cell carcinoma, urogenital malignancies, and vitamin D-resistant hypophosphatemic rickets. Extracutaneous abnormalities were detected in approximately 75% of PSS cases.

Congenital melanocytic nevi

The relative risk for melanoma arising within a congenital nevus is related to the size of the lesion. The timing of and clinical presentation of development of melanoma is also related to the size of the lesion. Medical decisions are individualized taking into account the perceived risk of malignancy, psychosocial impact, and anticipated treatment outcome. In this article, the common features of congenital nevi are discussed as well as the potential individual variations and their impact on treatment recommendations.

The group of epidermal nevus syndromes Part I. Well defined phenotypes

The epidermal nevus syndromes represent a group of distinct disorders that can be distinguished by the type of associated epidermal nevus and by the criterion of presence or absence of heritability. Well defined syndromes characterized by organoid epidermal nevi include Schimmelpenning syndrome, phacomatosis pigmentokeratotica, nevus comedonicus syndrome, angora hair nevus syndrome, and Becker nevus syndrome. The molecular basis of these disorders has so far not been identified. By contrast, the group of syndromes characterized by keratinocytic nevi comprises three phenotypes with a known molecular etiology in the form of CHILD (congenital hemidysplasia with ichthyosiform nevus and limb defects) syndrome, type 2 segmental Cowden disease, and fibroblast growth factor receptor 3 epidermal nevus syndrome (García-Hafner-Happle syndrome), whereas Proteus syndrome is still of unknown origin. From this overview, it is clear that a specific type of these disorders cannot be classified by the name "epidermal nevus syndrome" nor by the terms "organoid nevus syndrome" or "keratinocytic nevus syndrome."

LEARNING OBJECTIVES

After completing this learning activity, participants should be able to distinguish nine different epidermal nevus syndromes by their characteristic features, understand the practical significance of avoiding terms like "epidermal nevus syndrome" or "keratinocytic nevus syndrome" to define any specific entity within this group of disorders, and differentiate between nonhereditary traits and those bearing a genetic risk because of either Mendelian or non-Mendelian inheritance.

Nevus Spilus and Melanoma: Case Report and Review of the Literature

Background:

Nevus spilus is characterized by a pigmented patch with scattered flat or maculopapular speckles. Nevus spilus was first described by Burkley in 1842. Since then, this lesion has been widely debated in the literature, particularly for the possible occurrence of melanoma within the lesion.

Objective:

We describe the case of a 65-year-old female presenting with a nodular achromic melanoma that occurred within a nevus spilus on the left thigh.

Conclusion:

Our observation is consistent with the idea that this entity in some circumstances may have the ability to evolve into a malignant melanoma.

Carcinomas basocelulares múltiples sobre facomatosis pigmentoqueratótica

We present a patient with phacomatosis pigmentokeratotica (PPK) who developed several basal cell carcinomas on epidermal nevus lesions in adult life. PPK shows an elevated incidence of development of malignant lesions both on the sebaceous or epidermal nevus component as well as on the nevus spilus one.

Phacomatosis pigmentokeratotica associated with hemihypertrophy and a rhabdomyosarcoma of the abdominal wall

Phacomatosis pigmentokeratotica (PPK) represents a specific "twin nevus" syndrome in which a speckled lentiginous nevus (SLN) is associated with an organoid nevus with sebaceous differentiation. A boy with a large nevus sebaceus on the left face and upper part of the trunk, a giant segmental SLN extending from the abdomen to the feet bilaterally, and right hemihypertrophy developed an embryonal rhabdomyosarcoma of the right abdominal wall at age 6 months. A variety of musculoskeletal, neurologic, and ocular anomalies have been observed in patients with PPK, reflecting the individual manifestations of both SLN and Schimmelpenning syndromes. This report adds hemihypertrophy to the spectrum of extracutaneous manifestations of PPK and, to our knowledge, represents the first observation of a rhabdomyosarcoma arising in contiguity with an SLN in a patient with PPK. The development of a rhabdomyosarcoma in our patient likely reflects both increased propensity for growth (as evidenced by the hemihypertrophy) and the pluripotent nature of neural-crest derived cells within the field defect that underlies an SLN.

Mélanome sur naevus spilus : 5 observations

BACKGROUND

Nevus spilus is defined as café-au-lait macules with dark maculopapular speckles. Histologically, it has the aspect of lentigo associated with nevocellular nevus. There are 3 types of nevus spilus: small or medium-sized (<20 cm), giant and zosteriform. Malignant transformation of nevus spilus is rare.

PATIENTS AND METHODS

We analyzed the cases of 5 patients presenting melanoma within nevus spilus as well as 20 published cases. The evaluation criteria were: for nevus spilus: size, type, topography, age of onset and presence of dysplastic nevi within the nevus spilus; for melanoma: clinical aspect, histological type, thickness, level and age at diagnosis. The presence of other risk factors for melanoma was noted.

RESULTS

The 14 women and 11 men had a mean age of 49 years at melanoma diagnosis. Type of nevus spilus was: small or medium-sized (15 cases), zosteriform (6 cases) and giant (4 cases). Only 3 nevi spili were<4 cm in diameter. Nevus spilus was present since birth (11 cases), childhood (7 cases), after the age of 20 years (3 cases) and was unspecified in 4 cases. Three of our five patients had other risk factors for melanoma. Two patients were presenting 2 melanomas within nevus spilus. The histological type of melanoma was not specified in 8 cases but SSM was the most common type (13 cases). Median Breslow thickness was 1.25 mm (0.27 to 8 mm) for the 19 cases in which it was specified.

CONCLUSION

The following criteria appeared to be associated with risk of developing melanoma in nevus spilus patients: nevus spilus present since birth, nevus spilus over 4 cm in diameter, and giant or zosteriform nevus spilus. Development of melanoma within nevus spilus is a rare event. Consequently, guidelines for follow-up of nevus spilus cannot be defined. However, follow-up is recommended, and in particular, self-examination.

Two Distinct Types of Speckled Lentiginous Nevi Characterized by Macular versus Papular Speckles

BACKGROUND

Speckled lentiginous nevus (SLN; synonym: nevus spilus) is a darkly spotted light-brown macule that mostly occurs as an isolated lesion of rather limited dimensions but sometimes may involve large areas of the body. So far, this skin disorder has been considered to represent one clinical entity.

OBJECTIVE

Because SLN is occasionally associated with complex birth defects such as phacomatosis pigmentovascularis, phacomatosis pigmentokeratotica, or SLN syndrome, we tested our idea that two different types of SLN may exist, each one associated with a particular syndrome.

METHODS

A review of case reports on SLN published during the years 1970-2004 was performed.

RESULTS

This evaluation of cases provided evidence that two different types of SLN exist, in the form of macular versus papular SLN, each one being related to a specific syndrome. Macular SLN is characterized by a tannish-brown background with darker flat speckles. The distribution of speckles is rather even and resembles a polka-dot pattern. Histopathologically, this type of SLN is characterized by what has been called a 'jentigo' pattern in the darker speckles and by some nests of melanocytes at the dermoepidermal junction at the tips of the papillae, whereas the background pigmentation shows the microscopical features of a lentigo. Papular SLN is characterized by a light-brown macule superimposed by multiple melanocytic nevi in the form of papules or nodules that show a more uneven distribution reminiscent of a star map. Small dark macules may likewise be present. Histopathologically, the papular component consists of dermal or compound melanocytic nevi. A separation of the two types of SLN is important because our analysis showed that macular SLN is a hallmark of a particular type of phacomatosis pigmentovascularis, whereas papular SLN is typically present in phacomatosis pigmentokeratotica as well as in SLN syndrome.

CONCLUSIONS

Macular SLN and papular SLN appear to be two distinct cutaneous entities. This dichotomy may turn out to be important when such nevi will be analyzed at the molecular level.

Phacomatosis pigmentokeratotica: a 20-year follow-up with malignant degeneration of both nevus components

Phacomatosis pigmentokeratotica is a rare syndrome defined by the association of an organoid nevus occasionally with sebaceous differentiation, a speckled lentiginous nevus, and other extracutaneous anomalies. The disorder is a consequence of the so-called twin spot genetic mechanism. We describe the first occurrence involving malignant degeneration of both nevus components, giving rise to three basal cell carcinomas over the sebaceous nevus and a malignant melanoma of the superficial spreading type over the speckled lentiginous nevus. This observation, in concert with the other instances reported in the literature, points to the need for adequate patient follow-up to ensure early detection and treatment of any possible associated malignant degeneration.