PIGMENTED LESIONS Flashcards
(29 cards)
What is Amalgam Tattoo, and what is its most common site in the oral cavity?
Amalgam tattoo (focal argyrosis)
is the most common pigmentation of oral mucous membranes caused by the implantation of amalgam particles. The most common site is the mandibular gingiva.
How does Amalgam Tattoo appear clinically and histopathologically?
Clinically, it appears as brownish-black granules or solid fragments of variable sizes. If large, they may appear on an x-ray. Histopathologically, it shows mild foreign body granulation tissue reaction with macrophages, lymphocytes, and giant cells.
What is the fate of amalgam in an Amalgam Tattoo, and what is a caution mentioned regarding amalgam fillings?
Amalgam is slowly eroded, with mercury and tin lost, leaving silver residues. A caution is to use a rubber dam, especially during an amalgam filling.
What causes heavy metal pigmentation in the oral cavity?
Heavy metal pigmentation is due to environmental, occupational exposure, or therapeutic administration of metals like Bismuth, Arsenic, Gold, Lead,رصاص في مواسير المياه Mercury, and Silver.
How does heavy metal pigmentation typically appear clinically?
pigmentation that follow the gingival contour around the neck of the teeth.
How do drug-related discolorations of the oral mucosa appear clinically, and what types of drugs can cause them?
Most common site
they appear as localized or generalized zones of blue to ill-defined black pigmentation affecting any oral site, most commonly the gingiva, tongue, and buccal mucosa. Various drugs, including antibiotics, antivirals, antimalarials, chemotherapeutics, antifungals, antileprotics, and antihypertensives, can cause them.
What is a melanocyte, and where do they originate?
Melanocytes are melanin-producing cells
that originate from the neural crest and migrate to the skin and mucous membrane to reside between basal cells.
How do melanocytes synthesize melanin, and what is the function of melanin?
Melanocytes synthesize melanin from tyrosine by the action of the tyrosinase enzyme. Melanin is synthesized in specialized granules called melanosomes
protect nuclei of epithelial cells from
the damaging effect of actinic rays اشعه
What are some non-neoplastic lesions of melanocytic origin?
Physiologic pigmentation
Smoking associated melanosis
Café au lait Macules,
Lentigoكبر السن
Vitiligo بهاق
and Oral/labial melanotic macule and Ephelis.
What is a Pigmented Nevus (Melanocytic Nevi), and how do nevus cells differ from normal melanocytes?
a type of nevus arising from altered melanocytes known as nevus cells. Nevus cells are usually
1smaller in size,
2without dendrites,
3and less metabolically active than normal melanocytes.
Where are pigmented nevi commonly found in the skin and intraorally?
In the skin,
pigmented nevi are very common at any site in childhoodطفولة .
Intraorally, they are uncommon, with the most common sites being the gingiva (41%), hard palate (40%), and buccal mucosa (19%).
What are the types of pigmented nevi discussed?
The types discussed are
Acquired melanocytic nevus (junctional, compound, intradermal) and Variants of melanocytic nevus, such as Blue nevus.
Describe a Junctional nevus clinically and histologically, and its malignant potential.
it has nests of nevus cells at the dermo-epidermal junction and has malignant potential.
What is a Compound Nevus?
A compound nevus contains both a junctional element and an intradermal element. The junctional element is what makes them dangerous.
Why are only the junctional cells in nevi considered potent for malignant transformation?
Cells reaching the dermis (nevus cells) become smaller, lose their melanin synthesizing enzymes, and lose their power to proliferate.قدره علي التكاثر
What is an Intradermal Nevus, and where are the nevus cells located?
intradermal nevus= (intramucosal) is the most common type of nevus where the nevus cells are situated in the dermis.
Describe a Blue Nevus clinically and histologically.
a flat bluish lesion found on the skin and mucosa.
Histologically, it has spindle-shaped nevus cells deep in the dermis.
What type of nevi are most likely to undergo malignant transformation, and what clinical signs suggest this transformation?
transformation include a
large number of acquired nevi,
rapid enlargement in size,
ulceration,
change in color,
and regional lymph node enlargement.
What is Melanoma, and where is it commonly found?
Melanoma arises from malignant transformation of melanocytes. It is common in the skin and is the 3rd most common skin cancer, accounting for 5% of skin malignancies.
How does the incidence of melanoma differ in skin and orally among different racial groups?
Skin melanoma is common in whites more than blacks and Asians. Orally, it is common in blacks and Asians more than whites.
What are the two modes of growth for melanoma, and how do they affect prognosis?
Melanoma has a radial growth pattern (neoplastic cells at the junction of epithelium and connective tissue) and a vertical growth pattern (neoplastic cells penetrate epithelium and connective tissue). A long radial growth phase gives a better prognosis, while vertical growth leads to metastasis and a poor prognosis.
What system is used clinically to diagnose melanoma?
The ABCDE system is used to diagnose melanoma clinically.
Describe Lentigo maligna melanoma.
Lentigo maligna melanoma arises only in sun-induced skin (face). It has a radial growth phase (25-30 years), giving an excellent prognosis until it enters the vertical growth phase, leading to metastasis and poor prognosis.
Describe Superficial spreading melanoma.
Superficial spreading melanoma is the most common type in the skin of the body. It has a radial growth phase for several years before changing to a vertical growth phase, resulting in a better prognosis compared to types that start with vertical growth.
