Melanocytic tumors of uncertain malignant potential (MELTUMP) are melanocytic lesions in the dermis that cannot be classified by morphology as either benign naevi (moles) or malignant melanomas because the mass shows features of both. Several lesion types may be classified as MELTUMPs: these include atypical melanocytic proliferations with features that may overlap with atypical Spitz naevi/tumors, dysplastic naevi, pigmented epithelioid melanocytoma, deep penetrating naevi, congenital neavi, cellular nodules in congenital naevi, possible naevoid melanomas, and cellular blue naevi. A related category of melanocytic proliferation is superficial atypical melanocytic proliferations of uncertain significance (SAMPUS). This category, unlike MELTUMP, which implies as yet undetermined potential for metastases even after complete excision, signifies lesions without metastatic potential at time of excision but with potential to progress upon incomplete excision.
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Such naevi can also manifest themselves as beauty marks, which most commonly appear on the face, neck or arms.
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A nevus may also be spelled naevus. The plural is nevi or naevi. The word is from nævus, Latin for "birthmark".
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Tegumental angiomyxoma-neurothekeoma (TAN syndrome) is a syndrome, an acronym, and eponym proposed by Malaysian ophthalmologist of Chinese Descent, Tan Aik Kah (b. June 1975). Angiomyxomas are associated with LAMB (lentigines, atrial myxomas, muco-cutaneous myxomas, and blue naevi) syndrome, NAME (nevi, atrial myxoma, myxoid neurofibromas, and ephelides) syndrome and Carney syndrome (atrial, cutaneous and mammary myxomas, lentigines, blue naevi, endocrine disorders and testicular tumours). TAN syndrome is characterized by multiple superficial angiomyxoma and neurothekeoma confined only to the skin (tegument).
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Diagnosis is by clinical examination. Spider naevi are most commonly seen by general practitioners, or dermatologists. Whilst a lesion can be identified as a spider naevus, this is not a diagnosis in itself. The clinical picture should be indicative of whether there is underlying disease that should be investigated.
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The scalp is the most commonly involved area with lesser involvement of trunk and extremities. Frieden classified ACC with fetus papyraceus as type 5. This type presents as truncal ACC with symmetrical absence of skin in stellate or butterfly pattern with or without involvement of proximal limbs.Moss C, Shahidulla H. Naevi and other developmental defects.
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The exact etiology of ACC is still unclear but intrauterine infection by varicella or herpes virus, drugs such as methimazole, misoprostol, valproate, cocaine, marijuana etc., fetus papyraceus, feto-fetal transfusion, vascular coagulation defects, amniotic membrane adherence, abnormal elastic fiber biomechanical forces and trauma are implicated.Moss C, Shahidulla H. Naevi and other developmental defects. In: Burns T, Breathnach S, Cox N, Griffiths C, editors. Rook’s Textbook of Dermatology.
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Aplasia cutis congenita is a rare disorder characterized by congenital absence of skin. Frieden classified ACC in 1986 into 9 groups on the basis of location of the lesions and associated congenital anomalies.Moss C, Shahidulla H. Naevi and other developmental defects. In: Burns T, Breathnach S, Cox N, Griffiths C, editors. Rook’s Textbook of Dermatology. 8th ed. United Kingdom (UK): Wiley-Blackwell Publication; 2010. p. 18, 18.98-18. 106.
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Pigmented birthmarks caused by excess skin pigment cells include: moles, café au lait spots, and Mongolian spots. Vascular birthmarks, also called red birthmarks, are caused by increased blood vessels and include macular stains (salmon patches), hemangiomas, and Port-wine stains. A little over 1 in 10 babies have a vascular birthmark present by age 1. Several birthmark types are part of the group of skin lesions known as nevi or naevi, which is Latin for "birthmarks".
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A spider angioma or spider naevus (plural spider naevi) is a type of telangiectasis (swollen blood vessels) found slightly beneath the skin surface, often containing a central red spot and reddish extensions which radiate outwards like a spider's web. They are common and may be benign, presenting in around 10–15% of healthy adults and young children. However, having more than three spider angiomas is likely to be abnormal and may be a sign of liver disease. It also suggests the probability of esophageal varices.
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While Siemens focused on dermatological phenotypes, he also explored psychological features using twin studies. An example of this research was on the academic performance of identical and fraternal twins: His research found that identical twins were more likely to have a similar performance in school than fraternal twins. Siemens wrote in "Zwillingspathologie" about his findings: > "If an illness is regularly dominant, then both of the identical twins > either suffer from it or are free from it.. the nonidentical twins correlate > as the siblings of a two-child family .... With the help of twin pathology, > we found a possible way to judge hereditary influence on the investigated > features .... The assessment is based on the comparison of the findings in > identical and nonidentical twins." His research included reporting on similarities in skin traits in monozygotic twins, including naevi among other dermatological traits.
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Galton's article considered environmental factors such as social conditions and education; here, Galton faced objection that these environmental conditions were only a small part of the circumstances that could affect similarity of twins. Curtis Merriman, an assistant professor of Education at the University of Wisconsin, also published a report called "Psychological Monographs" on the twin method describing the difference between the identical and fraternal twins in 1924; however, Merrimen did not suggest that the difference between identical and fraternal twins could be used to explore hereditary traits and only interpreted his results as evidence for two types of twins. Siemens' work introduced the classical "Twin Method", which is recognized as highly influential by current Twin Studies experts in genetics. Hermann Werner Siemens was the first researcher to attempt to determine the roles of genetics and environment in the specific case of naevi, which are moles or birthmarks.
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