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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two cases of melanocytic lesions in lymph node associated with congenital naevus are presented. The first was a 30-year-old man with a nodular melanoma arising in a small congenital naevus. The second was a 2-year-old male infant with a giant congenital naevus. In both cases, naevus cell aggregates were observed in the capsule, trabeculae, perisinusoidal areas and lymphatic vessels surrounding the nodes. In the first case, clusters of large atypical melanocytes were present amongst naevus cell aggregates in the perisinusoidal areas as well as in the lymphoid parenchyma. Between the naevus cells and large atypical melanocytes, transitional forms were observed which supports the idea that the presence of large atypical melanocytes is indicative of benign naevus cells. In the second case, marginal sinuses were packed with clusters of large melanin-rich cells. Immunohistochemically, these cells were S-100 protein negative, but ultrastructural studies proved them to be melanocytes. They were considered indicative of spread of benign naevus cells via lymphatic vessels. Arrested migration of naevus cells during embryogenesis and benign spread of naevus cells are possible explanations for the histogenesis of naevus cell aggregates in lymph nodes associated with congenital naevus.
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PMID:Melanocytic lesions in lymph nodes associated with congenital naevus. 831 18

We report a case of a congenital melanocytic nevus accompanied by a mucous cyst and satellite pigmented macules on the undersurface of the left great toe in a 17-year-old Japanese man. Myxoid change was confirmed by the discharge of viscous liquid when conducting biopsy of the tumor. Besides such an unusual clinical feature of the tumor, accompanying satellite lesions led us initially to consider the possibility of malignant melanoma. However, a biopsy specimen obtained from the tumor revealed the typical features of intradermal type melanocytic nevus. In a specimen obtained from the satellite pigmented lesion, there was a small mass of nevus cells underneath the basement membrane zone, suggestive of having originated from the spread of nevus cells through lymphatic vessels.
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PMID:Congenital plantar melanocytic nevus with satellite lesions. 882 99

Classification of cutaneous vascular anomalies is difficult because conceptual confusion persists between vascular neoplasms and malformations. However, hemangiomas of the infancy fulfill criteria both for hyperplasia and neoplasm because they result from proliferation of endothelial cells, but often undergo complete regression. Despite these pitfalls we have classified cutaneous vascular anomalies into the following categories: hamartomas, malformations, dilatations of preexisting vessels, hyperplasias, benign neoplasms, and malignant neoplasms. In this first part of our clinicopathologic review of vascular anomalies, hamartomas, malformations, and dilatation of preexisting vessels are covered. Hamartomas include several combined vascular and melanocytic proliferations grouped as phakomatosis pigmentovascularis and the so-called eccrine angiomatous hamartoma that consists of proliferations of both eccrine glands and blood vessels. Vascular malformations result from anomalies of embryologic development, and in some of them the abnormalities of the involved vessels are more functional than anatomic, as is the case of nevus anemicus. In contrast, other cutaneous vascular malformations show striking morphologic abnormalities of the vascular structures. These anatomic vascular malformations are subdivided into the following groups: capillary, venous, arterial, lymphatic, and combined anomalies. Spider angioma, capillary aneurysm-venous lake, and telangiectases are not vascular proliferations at all, but dilations of preexisting vessels. In our opinion, most of the lesions described with the generic term of "angiokeratoma" are not authentic vascular neoplasms, but hyperkeratotic malformations of capillaries and venules or acquired telangiectases of preexisting blood vessels of the papillary dermis. Therefore the first group of these "angiokeratomas" are included in the vascular malformations section, and the second group are covered in the section of dilation of preexisting vessels. Lymphangiectases are considered the lymphatic counterpart of angiokeratomas because they result from ectasia of preexisting lymphatic vessels of the papillary dermis.
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PMID:Cutaneous vascular anomalies. Part I. Hamartomas, malformations, and dilation of preexisting vessels. 934 91

Vascular malformations and neoplasms are very common skin disorders, found in up to 5% of newborns. However, a clear distinction has to be made between proliferating vascular lesions and permanent malformations. An exact classification is also extremely useful, since many new specific diagnostic and therapeutic measures have been developed in recent years. True proliferating tumors are, for example, childhood hemangiomas, glomus tumors, granuloma pyogenicum, tufted angiomas, senile angiomas, and malignant vascular lesions. Vascular malformations can affect capillaries, veins or arteries, as well as lymphatic vessels. Arteriovenous shunts and combined malformations may also exist (Hamburg classification). Nevi flammei, nevi anaemici, hematolymphangiomas, angiokeratotic nevi, circumscribed venous-arterious malformations, and the blue-rubber-blebnevus-syndrome may either be infiltrating or circumscribed and are characterised by a persistence of the primitive vessel network. In contrast, other malformations involve various vascular trunks, showing vessel dilation or obstruction, often combined with changes in bone or soft tissue. Significant large vessel malformations are the Bockenheimer syndrome, the Klippel-Trenaunay syndrome and the Parkes-Weber syndrome. Combinations involving both large trunks and extravascular space such as the Klippel-Trenaunay syndrome also occur.
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PMID:[Classification of vascular abnormalities and neoplasms]. 941 Aug 45

Cutaneous melanoma preferentially metastasizes via the lymphatic route. However, the mechanisms of lymphatic invasion and metastasis to regional lymph nodes are poorly understood. Nitric oxide is a free radical molecule synthesized from L-arginine by nitric oxide synthases that plays a critical role in various physiological and pathological processes, including tumor growth and angiogenesis. We have tested whether inducible nitric oxide synthase expression correlates with lymphatic vessel density identified with D2-40 antibody and/or blood microvessel density identified with CD105/endoglin in a series of melanocytic nevi (n=28) and cutaneous melanomas (n=38), representative of various pT. Inducible nitric oxide synthase expression was significantly lower in melanocytic nevi in comparison with primary and metastatic melanomas (P<0.001). Mean microvessel density was significantly higher in primary and metastatic melanomas in comparison with melanocytic nevi (P<0.001 for intratumoral and P=0.001 for peritumoral vessels). Vertical growth phase melanomas showed a higher intratumoral microvessel density in comparison with radial growth phase melanomas (P=0.02). The number of peritumoral lymphatics was significantly lower in nevi as compared with primary and metastatic melanomas (P=0.01). No correlation between microvessel or lymphatic vessel and clinical outcome was found in melanomas. A significant direct correlation was observed between inducible nitric oxide synthase immunostaining in melanocytic tumor cells and the density of lymphatic vessels (peritumoral: P=0.001; intratumoral: P=0.08), and the density of peritumoral blood microvessel (P=0.02). Our findings support the hypothesis that inducible nitric oxide synthase is implicated not only in blood, but also in lymphatic vascular neoformation in melanoma. Mechanistic studies are needed to address the possibility that inducible nitric oxide synthase controls lymphangiogenesis, dissemination and lymphatic borne metastases.
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PMID:Inducible nitric oxide synthase expression in melanoma: implications in lymphangiogenesis. 1866 Jul 96

Herbivorous mammals such as nutrias, guinea pigs, chinchillas, and mole-rats have a longitudinal mucosal colonic groove (furrow) in their ascending colon, which is thought to play a role in the colonic separation mechanism (CSM). It is not known whether this groove is structurally modified to adapt to this function in mole-rat species. The morphology of this groove was studied in 32 mol-rats, four species, one of which consisted of three subspecies, endemic to southern Africa and two species found in eastern Africa. The macroscopic morphology of the groove was documented, and samples for histological examination were taken. The groove was wide at its origin at the cecocolic junction and was lined on either side by a row of papillae with the opposing papillae slightly offset in arrangement. The papillated groove gradually decreased in size toward the distal part of the ascending colon where it disappeared. This pattern was similar in all species except in Heterocephalus glaber, where the papillae were absent and the groove was lined by two longitudinal ridges. A histological examination of cross sections revealed that the mucosa covering the inner and outer walls of the groove was rich in mucous-secreting goblet cells. The walls of the groove contained smooth muscle extending from the inner circular smooth muscle layer at the base to the tips of the papillae in all species examined as well as arteries, lymphatic vessels, and prominent sinusoid-like veins. The groove could be demonstrated both macroscopically and histologically in three Bathyergus suillus fetuses of varying sizes. The sinusoid-like veins present in all grooves, regardless of macroscopic shape, suggest that they have a role in the functioning of the groove.
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PMID:The colonic groove or furrow: a comparative morphological study of six species of African mole-rats (Rodentia, Bathyergidae). 1927 39

In the following report we describe a medium-sized congenital melanocytic nevus (CMN) on the upper back of a female patient biopsied at 9 days of age. This case is a unique variant of CMN occurring in the neonatal period that mimics malignant melanoma. This is not only because of histologic features such as a large round or ovoid cellular phenotype of melanocytes mimicking melanoma cells but also because of conspicuous angiotropism, a finding not previously reported in such CMN. Immunostaining for blood and lymphatic vessels demonstrated angiotropism of melanocytes about blood vessels but not lymphatics. We have already emphasized the significance of angiotropism as a marker of extravascular migratory metastasis (EVMM) of melanoma. EVMM, a process by which tumor cells migrate along vessels and other tracks, has striking parallels with the migration of embryonic stem cells from the neural crest. Thus we propose, because angiotropism is a common finding in CMN and metastatic melanoma, that (1) such pathways of cellular migration may result in the genesis of CMN and other melanocytic neoplasms; and (2) the dysregulation of such embryonic pathways may result in the retrograde migratory phenomena of melanoma as already described. In summary, extravascular cellular migration of melanocytes seems to be fundamental for melanoma (perhaps other cancer) metastasis but also hypothetically may be important for the development of other melanocytic lesions such as CMN and requires further investigation.
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PMID:Angiotropic neonatal congenital melanocytic nevus: how extravascular migration of melanocytes may explain the development of congenital nevi. 2158 36

The present case describes classical intradermal nevus with intralymphatic nevus cell emboli. A 13-year-old boy presented with black colored macule on the shin 1 cm in diameter which was gradually increasing in size. Histopathology of the lesion was typical of an intradermal melanocytic nevus. The most notable feature of this case, however, was an occasional aggregate of nevus cells within a lymphatic vessel of the upper dermis. The nevus cells within lymphatic lumen had morphological features of type A nevus cells. The cells were roundtocuboidal, exhibited abundant cytoplasm with welldefined cell borders and formed nests. These nevus cell aggregates were surrounded by flattened endothelial cells. Due to its rarity, a lymphatic nevus cell embolus creates diagnostic issues for pathologists. This observation must not be interpreted as evidence of malignancy but significant as a rare histological feature. In other words, the nevus cells might have been transported through the lymphatic vessels as a "benign metastasis."
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PMID:Dermal Lymphatic Invasion: A Rare Feature in Benign Intradermal Nevus. 3059 14