Errant embryological migration is also believed to be the source of melanocytic nevus cell "rests," which can be observed in the capsules of lymph nodes. (medscape.com)
[ 3 ] Assuming that all precursors reach their final destination, the epidermis would represent the only postnatal source of melanocytic nevus cells, thus supporting the concept of Abtropfung . (medscape.com)
Benign5
[ 2 ] In contrast, most acquired melanocytic nevi are considered benign neoplasms. (medscape.com)
The term benign melanocytic nevus refers to a heterogeneous group of nonmalignant melanocytic nevi manifesting either as pigmented or nonpigmented cutaneous lesions. (medscape.com)
The prototypical benign melanocytic nevus is the common acquired nevus, which typically appears within the first 6 months of life, reaches maximal size and number in young adulthood, then disappears with advancing age. (medscape.com)
The pathogenesis of leiomyoma is characterized by benign smooth muscle neoplasm . (wikidoc.org)
ABSTRACT: Spindle cell-predominant trichodiscoma (SCPT) is a benign adnexal neoplasm, best categorized within the trichodiscoma-fibrofolliculoma continuum. (bvsalud.org)
Nevi16
Congenital melanocytic nevi are thought to represent an anomaly in embryogenesis and, as such, could be considered, at least in a sense, malformations or hamartomas. (medscape.com)
Melanocytic nevi occur in all mammalian species and are especially common in humans, dogs, and horses. (medscape.com)
Melanocytic nevi represent proliferations of melanocytes that are in contact with each other, forming small collections of cells known as nests. (medscape.com)
Melanocytic nevi commonly form during early childhood. (medscape.com)
However, genetic factors are also clearly involved in the development of some types of melanocytic nevi. (medscape.com)
Some kinships express an autosomal dominant condition (the so-called dysplastic nevus syndrome or the familial atypical multiple mole and melanoma syndrome), in which members have a large number of large nevi, sometimes hundreds, scattered over the integument. (medscape.com)
Melanocytic nevi have also been observed to develop or spread rapidly after blistering events, such as second-degree thermal burns, severe sunburns, or toxic epidermal necrolysis or in persons with genetic blistering diseases such as epidermolysis bullosa . (medscape.com)
In such instances, the development of so-called eruptive melanocytic nevi appears to be propagated by a traumatic stimulus, with scattering of melanocytic nevus cells over a large area within a zone of blistering and with the subsequent development of multiple independent melanocytic nevi within the injured area. (medscape.com)
In summary, the exact etiology behind the development of melanocytic nevi is complex and multifactorial and is incompletely understood. (medscape.com)
In contrast, congenital melanocytic nevi are perhaps best interpreted as congenital malformations. (medscape.com)
Evidence of errant embryological migration can be seen histopathologically within giant congenital melanocytic nevi. (medscape.com)
Go to Melanocytic Nevi for complete information on this topic. (medscape.com)
[ 2 ] This hypothesis detailed the sequential development of junctional, compound, and finally purely dermal melanocytic nevi. (medscape.com)
[ 10 ] Such alterations in genetic makeup and the cytokine milieu cause impairment of cellular signaling between keratinocytes and melanocytes, which presumably leads to the formation of melanocytic nevi. (medscape.com)
Studies from families with multiple melanomas and atypical nevi (familial atypical multiple mole-melanoma [FAMMM] syndrome, also known a sB-K mole syndrome) have identified germline mutations of the p16 gene ( CDKN2A ) on chromosome 9p21, which encodes a negative regulator of cell growth. (medscape.com)
Combined melanocytic nevi, comprising a Spitz nevus component in conjunction with another nevus type [usually acquired nevi] are not uncommon (Scolyer et al. (atlasgeneticsoncology.org)
Melanocytes1
Primary oral malignant melanoma (POM) is a rare, very aggressive neoplasm of melanocytic origin characterized by the proliferation of atypical melanocytes at the epithelial-connective tissue interface, associated with upward migration into the epithelium and by invasion of the underlying connective tissue. (waocp.com)
In 1893, Paul Gerson Unna, a German dermatologist, presented the concept of Abtropfung , in which melanocytic nevus cells develop in the epidermis, then "drop off" into the dermis over time. (medscape.com)
It is now established that melanocytic nevus precursor cells are derived from neural crest tissue and migrate to and populate the developing epidermis of the embryo. (medscape.com)
Malignant Melanoma1
Common non-epithelial neoplasms that may cause malignant effusions include malignant melanoma, sarcomas, and other neoplasms including germ cell tumors [ Figure 1 ]. (cytojournal.com)
Renal4
Wilms' tumors is a renal malignancy commonly occurring in childhood with classic histopathological features. (jiaps.com)
While the majority of the tumors present as renal masses, atypical presentations like extrarenal masses have also been known. (jiaps.com)
Oncocytoid Renal Cell Carcinomas After Neuroblastoma" Represent TSC-mutated Eosinophilic Solid and Cystic Renal Cell Carcinomas: Association With Prior Childhood Malignancy and Multifocality With Therapeutic Implications. (ufl.edu)
Granulomas associated with renal neoplasms: A multi-institutional clinicopathological study of 111 cases. (ufl.edu)
Heterogeneous group1
MEM comprises a heterogeneous group of neoplasms believed to originate from the neural crest. (wikipedia.org)
Tumors4
There are several variants of cutaneous melanocytic tumors, characterized by differing clinical and pathologic features. (atlasgeneticsoncology.org)
Spitz tumors include a group of cutaneous melanocytic tumors that share certain histologic features. (atlasgeneticsoncology.org)
Only some of these characteristics are seen in atypical Spitz tumors and spitzoid melanomas. (atlasgeneticsoncology.org)
While most tumors metastatic to the serous membranes are of epithelial origin, cytologists should be aware that non-epithelial neoplasms can also cause malignant effusions including sarcomas, melanomas, germ cell tumors, and, more rarely, brain tumors. (cytojournal.com)
Proliferation1
LCH is characterized by the proliferation of CD1a-positive activated Langerhans (not atypical Langerhans cell, morphologically)-like cells (LCH cells) generating inflammatory granuloma. (mayabouchenaki.com)
Tumor8
A malignant tumor of migratory neural crest (ectomesenchyme) remnants showing ganglionic, schwannian, melanocytic and rhabdomyoblastic differentiation. (wikipedia.org)
Retinoblastoma is the most common intraocular tumor in childhood. (jiaps.com)
Melanocytic neuroectodermal tumor of infancy is a relatively rare pigmented neoplasm that primarily affects the maxilla of infants. (jiaps.com)
We report a case of melanocytic neuroectodermal tumor in a three month-old child with a greater extent of neuroblastic differentiation. (jiaps.com)
Medulloblastoma is defined by the World Health Organization (WHO) as "an embryonal neuroepithelial tumor arising in the cerebellum or dorsal brainstem, presenting mainly in childhood and consisting of densely packed small round undifferentiated cells with mild to moderate nuclear pleomorphism and high mitotic count. (medscape.com)
Medulloblastoma is the most common malignant central nervous system (CNS) tumor of childhood, with an annual incidence of about 0.5-0.8/100,000 in children younger than 19 years. (medscape.com)
Diagnosing non-epithelial malignancies in effusion specimens based entirely upon their cytomorphologic features is difficult because these neoplasms often exhibit considerable morphological overlap and their cytomorphology can differ from the original tumor. (cytojournal.com)
Medulloblastoma is the most common malignant CNS tumor of childhood with an annual incidence of about 0.5-0.8/100,000 in children younger than 19 years. (medscape.com)
Epithelioid1
Merkel cell carcinoma (MCC), squamous cell carcinoma (SCC), pigmented epithelioid melanocytoma (PEM), and other rare skin neoplasms have a well-known risk to spread to regional lymph nodes. (hindawi.com)
Cellular1
On the cellular level, melanocytic hyperplasia and increased melanin production are common observations in sun-exposed skin. (medscape.com)
Adults1
4 Malignant effusions caused by non-epithelial neoplasms are more frequently encountered in children than in adults. (cytojournal.com)
Cells2
Ganglion cells can appear immature and atypical, they can be bi- or multinucleated and showing evidence of Nissl substance (2-6). (wikipedia.org)
As malignant cells have a tendency to round up in body fluids these non-epithelial neoplasms can therefore mimic reactive mesothelial cells and metastatic adenocarcinoma. (cytojournal.com)
Origin1
2. Shuangshoti S, Nestky MG (1971) Neoplasms of mixed mesenchymal and neuroepithelial origin. (wikipedia.org)
Present2
Pigmentation depends upon the amount of melanocytic element present. (jiaps.com)
Hemorrhagic pustules with a "blueberry muffin" appearance accompanied by respiratory failure in a neonate present a challenging differential diagnosis that includes infections and neoplasms. (thieme-connect.de)