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DESCRIBING ORAL SOFT TISSUE LESIONS
COLOR
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 COLOR
In order to properly record or chart an abnormal finding, a common
understanding of the various color changes associated with oral
lesions must be achieved. Click on any underlined, blue
text to see a picture of what is being described.
The vast majority of oral soft tissue lesions demonstrate some
color change. This section will discuss the following predominant
colors that are seen in oral soft tissue lesions: Pink,
red, white, and combinations
of red and white, blue,
yellow, purple,
gray, brown
and black.
 Color as perceived by the human eye represents light reflected from
an object.
The human skin and oral mucosa are translucent. Light penetrates
the covering epithelium to the various underlying layers of tissue
(lamina propria and submucosa). Thus the covering epithelium is
translucent.
As the incident light strikes each layer of tissue a portion is
transmitted (allowed to pass on)....absorbed....scattered.....and
reflected.
We perceive the normal oral mucosa as Pink
in color due to the reflection of light striking the capillary bed.
Pigments are present in all layers and influence the tissue color.
Normal tissue contains four primary endogenous pigments or biochromes:
- oxyhemoglobin
- reduced hemoglobin
- melanin
- lipofuscin
Hemoglobin is present in red blood cells. Two types: Oxyhemoglobin
and reduced hemoglobin, reflecting the oxygen concentration. Oxyhemoglobin has more oxygen
and imparts a bright red color.
Reduced
hemoglobin is less oxygenated and imparts a bluish
color.
Melanin
is brown pigment formed in specialized
cells known as melanocytes. The pigment particles are transferred
to malpighian cells of the epithelium. Since melanin is a significant
diagnostic indicator, it will be discussed in detail with brown
and black lesions.
Lipofuscin is yellow
pigment of the submucosal fat that is also found in the cornified
superficial layer of the epithelium, in sebaceous glands and blood
plasma.
The blood contributes more to normal and abnormal tissue
colors in the oral mucosa than any other single factor. The color
imparted by blood is due primarily to hemoglobin.
The redness or blueness of tissue reflects the relative
proportion of oxyhemoglobin and reduced hemoglobin in the underlying
vessels. The arterioles contain approximately 95% oxyhemoglobin
and 5,% reduced hemoglobin. The capillaries contain approximately
70% oxyhemoglobin and 30% reduced hemoglobin. The sub-papillary
venous plexus contains approximately 50% of each.
Other factors related to the effect of blood on tissue
color are:
- The number of blood vessels concentrated in an area.....the
more, the redder
- The degree of dilatation or constriction of the vessels...The
more dilated, the redder
- The thickness of the overlying connective tissue and epithelium
or the proximity of vessels to the surface...The closer to the
surface, the redder.
Due to the complex interaction of the tissue biochromes and other
secondary factors affecting tissue colors which this unit will discuss,
it should be noted that single pure colors, as we normally interpret
or see them, are rarely seen when dealing with soft tissue lesions.
| In determining the color of soft tissue
lesions, the predominant color, the color involving the greatest
surface area, should be noted first. Lesser color changes involving
smaller areas of the lesions may or may not be helpful in making
a diagnosis. The complex interaction of colors, and the pathophysiologic
implication of color changes (where known) will be discussed
as they relate to each predominant color included in this unit. |
Normal
oral mucosa color is predominantly Pink
but can vary from Pink
to dark brown depending on the
amount of melanin in the epithelium. Thus, rather than referring
to the normal oral mucosal color as "Pink,"
it will be referred to as "normal color."
The vermilion borders of the lips, alveolar mucosae, soft palate,
and pharynx show more variation in color. In people with little
melanin, the lips may be more red,
due to the prominent vascularity and nonkeratinization of the epithelium.
In people with dense melanin deposits, the lips and gingiva may
appear very dark brown. You have to look at each person's entire oral
mucosa and establish in your mind what appears to be the "normal"
color for that individual.
Normal mucosal color in elevated lesions indicates the
pathology is submucosal in origin:
The surface mucosa has not been altered significantly, and the
mucosal color is intact. Elevated
lesions with a normal color most commonly manifest clinically
as nonblisterform lesions, or as generalized lesions, tumors,
nodules, or papules.Elevated normal color lesions may be due to
one of several forms of underlying pathosis, most commonly hyperplasia,
neoplasia, fluid accumulation, or cyst formation.
Hyperplasia
results from an increased quantity of normal tissue. In the oral
cavity, normal color
elevated lesions resulting from hyperplasia usually represent
hyperplasia of connective tissue or bone.
Neoplasia
an abnormal new growth of tissue or a cellular infiltrate which
may be benign or malignant. Thus a benign
or malignant neoplasm may be normal color.
Fluid accumulation
in elevated normal
color lesions is usually due to deep accumulation of
fluid. If fluid accumulation is superficial, the lesion will
be more translucent and the color will vary according to the color
of the underlying structures.
Cysts
generally well localized lesions which represent a fluid-filled,
epithelial-lined cavity.
Normal-colored,
depressed lesions
Rare. However, such unusual lesions as developmental pits, clefts,
or perforations will often be normal color. Atrophic scars may
also have a normal color.
Some flat
lesions of the tongue
may also be normal color. These are unique lesions which result
simply from the loss of normal lingual papillae.
Tongue lesions which result
from loss of papillae
may appear as dark
normal color or red
as the result of contrast with the surrounding papillae which
are heavily keratinized. These should be considered normal color.
 Melanin-related normal variations:
Melanin pigment causes normal variations from the Pink
color of the oral tissues. This pigment is normally more prominent
in African Americans, Asians, Native Americans and people of Mediterranean
and Middle Eastern nationalities.
Melanin
pigment concentrations are most common on the buccal mucosa,
attached gingiva, and hard palate. Normal melanin pigmentation may
be patchy or diffuse. It may cause the color of the mucosa to be
brown to bluish-black,
depending on the amount of melanin present. As discussed earlier,
blood is the most significant factor influencing red
color change. An increased quantity of blood to an area will result
in an increased redness or erythema.
 Redness or erythema - a variation
of Pink
Redness
or erythema may be localized or widespread, ranging from
minute macules to involvement of large areas of skin or mucosa.
Erythematous changes may occur without alteration in the morphology
of the site. Red may be the
predominant color in lesions of any morphology.
Redness or erythema may be caused by an increased quantity
of blood, resulting from dilatation of existing blood vessels and/or
proliferation of new vessels. Dilatation may be due to internal
factors, such as naturally secreted substances that cause vasodilation
or external factors involved with the inflammatory process that
cause vascular dilatation and proliferation.
 Lesions
Inside the oral cavity, the most obvious articles that appear white
or a variation of white are the teeth. But bear in mind,
approximately 50% of the soft tissue lesions of the oral cavity
may appear as white lesions.
| White lesions of the oral mucosa are mostly
due to alterations in the epithelium or alterations in the connective
tissue. In some instances, the changes may be a combination
of epithelial and underlying connective tissue changes. |
The most common causes of white lesions of oral mucosa relate
to changes in the epithelium:
- hyperkeratinization
- acanthosis
- necrosis
- fluid accumulation.
Hyperkeratinization
one of the most frequent epithelial changes. Hyperkeratosis,
the term for a thickening of the outer surface (keratin layer)
of the epithelium is analogous to a callus on the skin. This excessive
build-up and retention of surface cells alters the translucency
of the epithelium by absorbing fluid from the environment and
turning white. Chronic irritation and various other etiological
factors can cause an alteration in epithelial cell maturation
which also results in hyperkeratosis.
A very important point:
| Hyperkeratosis is a MICROSCOPIC
term. You cannot see hyperkeratosis with the naked eye. All
you can see is the white color that is the result of
hyperkeratosis. Thus when you are speaking clinically you should
use the descriptive clinical term WHITE LESION on the
oral mucosa. OR, if the white lesion is a flat plaque
on the mucosa, you can call it a LEUKOPLAKIA. Either term is
OK for a flat plaque on the mucosa, but if the lesion is a lump,
for example, or other than a white plaque, the term white
lesion is preferred. |
Acanthosis
Another common MICROSCOPIC epithelial change. Acanthosis is an
increased thickening caused by hyperplasia of the prickle cell
layer. When the epithelium becomes thickened by acanthosis, it
becomes less translucent and more white because of decreased
reflection of light from the normal capillary bed.
Necrosis
A common cause of white change, necrosis is death
of cells in a localized area which can result in a slough when
extensive areas of the epithelium become necrotic. Necrosis frequently
follows moderate or severe inflammation but it may also be the
result of physical or chemical trauma.
Increased fluid accumulation
Seen within the cells of the epithelium or beneath it, intracellular
edema can cause a pale white appearance of extensive
areas of oral mucosa. This is often associated with conditions
involving the labial and buccal mucosa.
Extracellular accumulation
of fluid
Beneath the epithelium, extracellular
fluid can also alter light reflection resulting in a white
color change. This holds for cysts or accumulations of other fluids
such as edema or mucin.
Changes in the connective tissue
In addition to or instead of changes in the epithelium, an increased
quantity of collagen or an alteration in maturity of collagen
may result in white lesions. Increased quantity of collagen
above the capillary bed decreases the reflection of red
color to the surface. An example of this change can be seen in
fibromas or scars.
Some white lesions may be due to both epithelial and connective
tissue changes.
The morphologic characteristics most often associated with white
lesions are plaques and papules because these are
primarily the result of epithelial alteration. Nodules and tumors
are usually due to changes in the connective tissue. If allowed
to persist they will frequently show a white change due to
secondary hyperkeratinization. This
hyperkeratinization is the result of mechanical friction from opposing
structures during normal masticatory function.
Pallor is a unique variation of the white color change.
Pallor
is a minimal white change of the skin or mucosa most commonly
seen in nonkeratinized and melanin-free sites such as the vermilion
zones, fingernail beds, and conjunctival mucosa of the eyes. Pallor
may be due to a decreased flow of blood, decreased hemoglobin content,
or from an actual loss of hemoglobin.
 Red and White Color
Red and
white lesions commonly indicate the presence of inflammation.
Large
ulcers, or depressed lesions are the most common
morphologic characteristic associated with red
and white color.
An inflamed lesion, which was
originally red, may exhibit
some white coloration as a result
of necrosis and sloughing. Conversely, lesions originally
white in color may undergo some red
changes as a result of inflammation.
Some lesions such as superficial burns or fungal infections are
white lesions initially, but when rubbed, result in the partial
loss of the necrotic white surface. This leaves a denuded
red area due to exposure of
the capillary bed. Some large elevated lesions having a white
hyperkeratotic surface undergo trauma which causes thinning
and loss of the epithelial surface resulting in a red
and white lesion. In either case the process of rubbing off
the surface or traumatic thinning and denuding is called erosion.
Red and white
color is frequently associated with dysplastic or malignant  change in epithelium.
This is because dysplastic or frankly malignant epithelium
is more friable and less durable than normal and thus more subject
to injury. Also, malignant or dysplastic epithelium is less
prone to heal normally once injured, therefore it retains a
red and white injured
appearance.
| It is important to put this observation
in perspective so you won't be suspecting every red
and white lesion to be a malignant one. Remember,
reactive lesions such as trauma and inflammatory lesions such
as lichen planus are far more frequently encountered than
malignant or dysplastic lesions. Also, malignant and dysplastic
lesions often are associated with risk factors, for example
heavy smoking and alcohol consumption. This is why factors
such as age, sex, race and history are important to consider
along with clinical appearance. An important point to remember
is that dysplastic or malignant change cannot be determined
by the naked eye. A microscopic examination is always necessary
to distinguish benign from malignant. |
When determining the color of red
and white lesions, the predominating color should be selected.
If the red and white
colors are approximately equal, the lesion should be indicated as
red and white.
 Gray Color
Gray is a relatively uncommon
color in the mouth. Gray is
not due to a biologic pigment but usually results from deposition
of foreign material in the connective tissues. The gray
color may be localized or diffuse.
Localized gray pigmentation
This usually results from implantation
or deposition of foreign materials into lacerations or abrasions
of the mucosa. The most common foreign particles encountered
in the oral mucosa are amalgam or gold particles. These particles
can be driven into the mucosa at high speed when finishing or
polishing restorations. Amalgam is used in deciduous teeth as
well as permanent. Amalgam fragments may be broken off teeth during
extraction and fall into the extraction site leaving a gray
discoloration after healing, provided they are close enough to
the surface.
Diffuse gray pigmentations
These may result from heavy
metal ingestion with subsequent systemic deposition of
the material. This is seen in silver, lead, bismuth or mercury
poisoning. Discoloration of this type can occur in both gingiva
and unattached mucosa. The color may
vary from gray to
dark brown to black.
Natural brown pigments
Melanin or hemosiderin
may occasionally appear as a gray
color clinically. Since some of the reflected light from the material
is absorbed as it passes through the thickness of the mucous membrane
they appear gray rather than brown.
This gray color change may
be localized or diffuse. The natural grayness of some of the oral
mucosa in African Americans is an example of a brown
pigment, melanin, appearing as a gray
color clinically.
Heavy
concentrations of a pigment in the lamina propria may make
the gray color very dark, almost black.
Gray color is most often associated with
macules, since usually the amount of pigmented material is not sufficient
to raise or otherwise alter the normal contour of the mucosa.
 Blue Color
Blue is a relatively uncommon
color in the mouth. It is the predominant color in approximately
13%, of oral lesions.
Blue is not a biologic pigment.
However the color blue is usually
associated with two types of lesions. Some cystic lesions containing
clear fluid appear blue, some
vascular lesions are blue and tattoos often are
blue.
Cysts
within soft tissue
Those which contain clear fluid such as mucin appear pale blue
clinically. The exact reason for this blue
appearance is not understood but may relate to absorption and
reflection of light passing through the overlying soft tissue
and the contents of the cyst itself.
Vascular
lesions
These may appear blue when
the blood within the lesion contains a large amount of reduced
hemoglobin. This blue color can be seen through the translucent mucosa.
The shade of this blue color
may be altered by the thickness of the overlying mucosa. A darker
blue or even reddish is seen with a more superficial
lesion. A lighter blue is
seen with a deeper lesion.
Cystic and vascular lesions are relatively large blisterform
lesions. The morphology most often associated with blue
color is a bulla. This does not mean always.
Tattoos
from foreign bodies may appear as blue
macules.
 Purple Color
Purple is also
a relatively uncommon color in the mouth.
Purple color is often associated
with vascular lesions and deposition and interaction of pigments.
Vascular
lesions
Some appear blue, others
may appear purple. The perception
of purple is due in part to the basic bluish color
being modified by the normal Pink
or reddish mucosa. Purple
color may also be due to the combination of both oxygenated and
reduced hemoglobin in the blood.
Deposition and interaction
of pigments
Pigments from breakdown products of extravasated blood may cause
a purple discoloration. Purple
lesions resulting from deposition
and interaction of pigments are usually macules, nodules or
tumors.
Purple vascular lesions
are often bullae.
Bleeding into blisterform lesions and hematomas may
cause a purple discoloration.
Brown Color
Brown is a relatively uncommon
color in the mouth.
Brown coloration may be caused
by melanin or hemosiderin.
| Melanin is a substance produced
within melanocytes by structures called melanosomes. Melanocytes
are normally found near the basal layer of cells within the
epithelium. Not all melanocytes are functionally active at any
particular time so that even oral mucosa which is not pigmented
clinically, does contain melanocytes. An increase in brown
pigmentation may be brought about by an increased number
of melanocytes, increased melanin synthesis of
available melanocytes, and an increased size of melanosomes. |
Brown pigmentation due
to melanin usually appears as a macule but may also appear as a
nodule
or tumor.
Hemosiderin
may also be a source of brown
coloration. You will recall that hemosiderin is a breakdown product
of hemoglobin following extravasation of blood. Brown
color resulting from hemosiderin is most frequently associated
with crusting and drying of ulcerated
lesions on the vermilion zones and skin.
 Black
Color
Black is a relatively uncommon color in the mouth. Black
is the predominant color in approximately 7% of oral lesions.
| The most common cause for black color
in the mouth is foreign body deposition. Less frequently,
a black color may result from altered blood pigments,
necrosis and gangrene of tissue, and dense
accumulations of melanin pigment. |
Darkly
colored foreign materials
Beneath the oral mucosa foreign particles may appear as black.
Amalgam or gold particles beneath the oral mucosa, although usually
Gray, often appear as black. Black
lesions caused by foreign body deposition are usually macules.
Alteration
in blood pigments
Loss of epithelium in ulcerative lesions may allow the escape
of blood onto the surface of the mucosa. If an alteration in blood
pigments occurs, such as with oxidation and drying, a black
color may appear in the crust. Black lesions caused by
breakdown of blood pigments are usually macules.
Extravasated blood
Blood in the tissue in the form of a hematoma undergoing degradation
may appear as a black lesion (or a "black and blue"
mark) .
Tissue
death or necrosis
With invasion of saprophytic organisms, gangrene occurs. This
process is characterized by black color. When necrosis
and gangrene of tissue result in a black color, the lesion
usually undergoes a macular change. As the dead tissue sloughs,
a depressed lesion with a black periphery is formed.
Heavy
concentrations of foreign or biologic pigments
This may result in a black appearance. For example, melanin,
which is brown, in very heavy
concentrations, may appear black. Dense concentrations
of melanin pigment causing a black lesion usually appears
as a macule, but may also appear as a nodule or tumor.
Yellow Color
Yellow is a relatively
uncommon color in the mouth.
| Yellow
color may be caused by lipofuscin (the pigment of fat).
It may also result from other causes such as accumulation
of pus, aggregation of lymphoid tissue, exudation
of serum, degeneration of blood pigments, lipid
containing structures, neoplasms and extrinsic
stains |
Accumulation
of pus
Pus from degenerating leukocytes takes on a yellowish tinge seen
in acute inflammation. Thus a yellow
color may be seen in association with ulcers or pustules.
Lymphoid
tissue
Lymph tissue located superficially beneath the oral mucosa may
present as yellow to yellow-orange
papules or nodules, a common finding on the posterior tongue or
pharynx.
Serum
Serum is normally a yellow
or straw-colored fluid. Exudation of serum in an inflammatory
reaction may reach the surface if loss of epithelium has occurred.
If drying occurs, as on the lips, a crust may form. This crust
may take the form of a rough, yellowish plaque or may be seen
at the periphery of an ulcer.
Degeneration of blood pigments
Degenerating blood pigments , particularly in the formation of
bilirubin, may result in a yellow
color either localized or diffuse.
Excess
bilirubin in the tissues
A diffuse yellow color may
occur if there is breakdown of bile pigments as in liver disease,
blockage of the bile ducts, or excess bilirubin formation in hemolytic
disease. This condition is jaundice and is a diffuse macular change.
Lipid, or fat, is yellow
Accumulation of fat near the surface such as occurs in obesity,
in neoplasms, and as a result of abnormalities of lipid metabolism
may cause a yellow color. Normal
lipid-containing structures, such as Fordyce's granules,
usually appear as yellow papules.
A fat-producing neoplasm
Localized accumulation of fat in neoplasms produces a yellow
lesion with the morphologic characteristics of a nodule or tumor.
Abnormalities of lipid metabolism
Localized deposition
of fatty substances may occur in systemic metabolic diseases.
These present as yellow papules,
nodules, or plaques.
Extrinsic stains
Staining of tissues, especially of white lesions may cause
a yellowish color. For example, use of tobacco may cause a white
lesion to assume a yellowish color. Extrinsic stains usually involve
hyperkeratotic areas such as plaques or nodules. When this occurs,
white should be considered as the predominant color.
| Yellow
is the predominant color in lesions of many different morphologies.
Yellow may appear in any
morphology with the possible exception of a bulla. |
 Translucent
lesions (totally transmits light)
| Clinically, it is usually quite simple to distinguish
between blisterform and nonblisterform lesions by palpation.
You will recall from the morphology section that many blisterform
lesions can be distinguished from nonblisterform lesions by
their translucent quality. Lesions which appear translucent
are blisterform. The translucency as well as the associated
color of the lesions can be significant factors in differential
diagnosis. Both the translucency and associated color change
of a lesion are accurate indicators as to the nature of the
fluid content and its proximity to the surface. |
Translucent Pink lesions
These usually indicate an accumulation of a relatively clear
fluid such as serum,
mucin, or lymph. The covering
mucosa has a relatively normal thickness which allows blood
in the overlying tissue to color the lesion.
Translucent blue
These lesions may represent clear
fluid or blood accumulation. The blue
color from clear fluid accumulation indicates a superficial
lesion covered by a thin mucosa which causes absorption
of most of the visible wavelengths of light except blue
which is reflected.
Translucent Red or purple
These lesions usually indicate blood
accumulation which may be either intravascular or extravascular.
Most lesions that demonstrate a translucent quality
are bullae or vesicles.
 Summary
This section has reviewed the nine colors associated with oral
soft tissue lesions. Pink, red,
white, and combinations of red
and white are the most common colors encountered whereas
blue, yellow,
purple, gray,
brown, translucent and black
are uncommon colors for oral lesions. If you want to return to any
of the color sections, just click on the color in this paragraph.
Return to TOP of color section.
Pure colors are extremely rare when dealing with soft tissue lesions.
The primary and secondary factors causing and influencing tissue
colors are varied and complex. Blue
and gray lesions may be extremely difficult to distinguish.
Fine distinctions between colors are the result of perception of
color by the observer. Thus what is Pink
to one person may be red or
reddish to another. Similarly
blue and purple distinctions are not always easy to make.
In general, the more common colors such as Pink,
red, white and red
and white are less significant in leading to a specific diagnosis;
however, colors such as blue, gray,
Yellow, purple,
black, and brown may be highly significant
in making an accurate clinical diagnosis.
| A final word about clinical diagnosis of
oral soft tissue lesions: With most clinical lesions, it is
impossible to make a final diagnosis with absolute certainty.
As your clinical experience broadens, and you mature in your
judgement, you will acquire significant expertise that will
make your clinical diagnoses frequently accurate. NOTHING, HOWEVER
CAN SUBSTITUTE FOR A BIOPSY (INCISIONAL OR EXCISIONAL). If
the lesion is present under your observation for 2-3 weeks and
you cannot point to a specific cause, you should biopsy the
lesion. The procedure is simple, safe and the peace of mind
for you and the patient is well worth the expense. |
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