A dysplastic nevus or atypical mole is a nevus mole whose appearance is different from that of common moles. These nevi may look different from the gardenvariety uniformly pigmented round nevus, but their different appearance should not trigger the alarm for melanoma, and they do not require excision. Nevoid malignant melanoma, mall cell type compound nevus similarities. Herein we describe the eclipse nevus and the cockade nevus. This form of a congenital naevus is also known as a. Design digital dermoscopic images of clark nevi were classified according to structural features, ie, reticular, globular, or. The natural history of melanoma over time and the time that it takes for an atypical nevus to progress to melanoma are largely unknown. Melanocytic nevi, which are benign tumors of melanocytes, may have occasional cosmetic significance but, for the most part, they are important only in relation to melanoma. Common moles, dysplastic nevi, and risk of melanoma. Clinically, dysplastic nevi show variation in size, shape, and coloration.
Dysplastic melanocytic nevus has been a subject of controversy in the last 20 years. Both children and adults can be affected by malignant melanoma arising in a giant congenital nevus. In this section, you will find excerpts directly from dr. Melanoma arising in a giant congenital melanocytic nevus. Halo nevi are also known as suttons nevi, or leukoderma acquisitum centrifugum. What is a congenital melanocytic naevus a congenital melanocytic naevus american spelling nevus is a proliferation of benign melanocytes that are present at birth or develop shortly after birth 1. A giant congenital melanocytic nevus gcmn is found in 0. The lesion was an irregular, flat, brown 2 x 2 cm lesion over the left forearm. A spitz nevus is a rare type of skin mole that usually affects young people and children. Clark compound nevus, mm wide,yearold male, biopsy con rmed. It is due to an overgrowth of the epidermis upper layers of the skin, pigment cells melanocytes and hair follicles. These are features that are also seen in melanoma, and it is a matter of degree that allows for the clinical distinction of dysplastic nevus from common nevus or melanoma.
The occurrence of an atypical dermoscopic pattern in spitz nevus is well recognized as is the occurrence of mela. A, an atypical proliferation of solitary units of melanocytes is present along the dermalepidermal and infundibular dermal junctions. Clark and breslow staging melanoma skin cancer cancer. World health organization of tumors, 4th ed volume 11. Other terms include clark nevus or melanocytic nevus with architectural disorder. Melanocytic nevus an overview sciencedirect topics.
Halo nevus also known as leukoderma acquisitum centrifugum, perinevoid vitiligo, and sutton nevus. Giant congenital melanocytic nevus gcmn is usually defined as a melanocytic lesion that is present at birth and will reach a diameter of. Protocol for the examination of biopsy specimens from. A variant of conjunctival melanocytic nevus, which tends to be seen in young children, that is associated with a greater extent of architectural disorder than usually seen has been referred to as atypical nevus of the conjunctiva or juvenile conjunctival nevus. Clinically, spitzoid melanomas usually evolve from amelanotic nodular lesions, growing to 1 cm or more in diameter. However, even after multiple nih consensus conferences and studies to examine reproducibility of dysplastic nevi by pathologists andor clinicians studying these lesions4, 1018, no single definition or name for these melanocytic nevi has yet been accepted by all pathologists, dermatopathologists, dermatologists, oncologists, other clinicians, epidemiologists, or geneticists4, 7, 8, 16. Gcmn is the main risk factor for the development of melanoma in childhood. Dysplastic nevi are described as being on a continuum between common acquired nevi and melanoma because they are morphologically and biologically intermediate between these 2 entities. Rather, these scalp nevi should be considered markers for a potentially higher lifetime risk of melanoma because they are seen more. The prevalence of nevus associated melanoma varies across studies. Some dermatopathologists have suggested abandoning this concept to use clark s nevus term for a large. Clark et al 1 described the atypical, or dysplastic, nevus as having unusual clinical and pathologic features found in individuals or families predisposed to melanoma. Second, by removing their dns, one could potentially prevent the development of melanoma.
It has been considered that most cutaneous malignant melanomas arise from pre. Some people have only a couple of dysplastic nevi, but other people have more than 10. Dif ferential diagnosis of pigmented spitz nevus may include hyperpigmented clark nevus and melanoma 4,5. Herein, we report the case of a patient who developed nodal melanoma metastasis under. Long term clinical and dermoscopic followup of a child. Melanoma arising in congenital nevus melanoma arising in a blue nevus uveal melanoma various sun exposure nodular melanoma nevoid melanoma references 1. A national institutes of health consensus conference 2 further defined atypical nevi as having diameter greater than 5 mm, color or border irregularity, and certain histologic features. They tend to be larger than nondysplastic nevi, typically exhibit some degree of asymmetry, and have somewhat irregular illdefined borders fig. In 1992, the nih recommended that the term dysplastic nevus be avoided in favor of the term atypical mole. The patient is a 70yearold white female who has had a longstanding, pigmented nevus over her left forearm. An atypical mole may also be referred to as an atypical melanocytic nevus, atypical nevus, bk mole, clark s nevus, dysplastic melanocytic nevus, or nevus. Although it can look like a serious form of skin cancer called melanoma, a spitz nevus. Select the bookmark tab or the thumbnail tab from the left hand edge to open the indexes.
Many clinical and histopathological studies seem to support this concept. Up to 95% of gcmns harbor nras mutations, and mutations in the braf, mc1r, tp53, and gnaq genes have also been. No biopsy needed for eclipse and cockade nevi found on the. Location of pink as an indicator of melanoma in dermoscopic images. A dysplastic nevus may occur anywhere on the body, but it is usually seen in areas exposed to the sun, such as on the back. Clinical and histopathological evidence suggests that melanoma develops in a sequence of steps, progressing from benign proliferative lesions, to primary melanomas that do not show evidence for metastasis, to invasive primary lesions, and to metastases. Recently she noticed some change with pruritus and increase in size. Dysplastic nevus originally proposed by clark s group is a key entity of the intermediate lesion between benign nevus and. If present, the lesion has a chance of about 6% to develop into malignant melanoma. Simple excision of an atypical nevus therefore does not obviate the patient from close dermatologic followup. The authors report on the morphologic changes of an atypical nevus by. It develops during childhood or adolescence on the shoulders or upper trunk, occasionally elsewhere. This is different to the number staging system that doctors also use.
Spitzoid melanoma is a subtype of melanoma that, clinically and histologically, resembles a spitz nevus. Histological comparison of nevoid melanoma and nevus. B, solitary units of melanocytes predominate along the dermalepidermal junction. Dermoscopic classification of atypical melanocytic nevi. Clark material handling usa 700 enterprise drive lexington, kentucky 40510 tel. Dysplastic nevus syndrome an overview sciencedirect topics. Clark nevi atypical melanocytic nevi can be considered as risk markers and potential precursors of melanoma. The clark scale and breslow thickness describe how deeply the melanoma has gone into the skin. This section discusses these starting with cancer, hiv and then other illnesses. A dysplastic nevus may also appear in areas not exposed to the sun, such as the scalp, breasts, and areas below the waist 1, 3. Nevi with architectural disorder and cytologic atypia of melanocytes nad, aka dysplastic nevi, have varying degrees of histologic abnormalities. A becker naevus nevus in american spelling is a lateonset epidermal naevus or birthmark occurring mostly in males.
819 703 1368 136 764 979 316 675 1363 536 243 1396 874 276 471 180 1220 961 35 12 241 197 539 941 151 293 1217 1541 867 920 633 1108 391 148 1073 1331 813 364 110 519 297 594 25 1075