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DESCRIBING ORAL SOFT TISSUE LESIONS
MORPHOLOGY
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 MORPHOLOGY
In learning to make a differential diagnosis of soft tissue pathosis,
the first step is to recognize the presence of an abnormal change,
either in function or structure, during a clinical oral examination.
In this series of presentations, we will only be concerned with
structural changes. Click on any underlined, blue text to see a picture of what is being described.
In order to properly record or chart an abnormal finding, a common
understanding of the morphology or oral lesions must be achieved.
All lesions of the oral cavity can be placed in one of three broad
morphologic categories:
(1) Elevated
(2) Depressed
(3) Flat.
 Elevated, Depressed and Flat lesions
can exist in specific basic forms which are  referred to frequently in texts and literature.
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As you encounter various oral lesions, you should
be able to answer questions such as:
Is the lesion elevated, depressed or flat?
Is it generalized or localized?
Is it single or multiple?
Is it fluid filled or not?
What is the character of the fluid, if present?
What is the approximate size (use millimeters and centimeters)
of the lesion?
Is it larger at the base or on the top?
If multiple lesions are present, are they separate or coalescing?
In fact, the way you will know whether or not you have learned
this material is when you encounter an oral lesion, do questions
like these automatically come up in your mind.
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ELEVATED LESIONS:
- An elevated lesion is one in which the surface is
above the normal plane of the mucosa.
- All elevated lesions are not necessarily symmetrical but may
have irregular contours.
- Clinically, it is quite easy to determine that a lesion is elevated
by looking at the lesion at different angles and relying on stereoscopic
vision.
- Perspective is helpful since an elevated lesion may hide or
cover any normal structures.
Elevated lesions may be localized
or generalized.
- A localized elevated lesion is limited to a small, focal
area.
- A generalized elevated lesion involves most or all of
an area or site. Some generalized lesions may involve more than
one site.
- It is usually easier to determine the limits of involvement
of localized lesions than of generalized lesions.
- Localized lesions may be single or multiple.
The number of lesions are often characteristic for a particular
disease. A single lesion is one lesion of a particular
morphology. Where more than one lesion of a particular morphology
is present, they are considered as multiple lesions.
Elevated lesions may be further divided into blisterform
or non-blisterform
lesions.
| Blisterform lesions are those which contain
a body fluid, usually identified by their characteristic translucent
appearance. Tactile examination of a blisterform lesion
will reveal a soft rebounding sensation. Blisterform
lesions are given descriptive names, depending on their
size and the material contained within the blister. A blisterform
lesion is either a vesicle, pustule, or bulla. |
- A vesicle
is a blisterform lesion which is less than 5 mm in
its greatest diameter and contains serum or mucin.
The serum or mucin gives the vesicle a clear or translucent,
slightly white appearance. Vesicles in the oral cavity are often
collapsed due to trauma, creating a collapsed
vesicle which appears white or cream colored.
A pustule
is a blisterform lesion that contains pus which
imparts a yellowish coloration. It may be greater or less than
5 mm.
- A bulla
is a blisterform lesion larger than 5 mm in
its greatest diameter which may contain serum or mucin.
It may occasionally contain extravasated blood. The color may
appear clear, red or blue, depending upon the fluid content. Similar
to vesicles, bullae often collapse due to trauma in the oral cavity
and are termed collapsed bullae which
are white or red in color.
| Non-blisterform lesions are solid and
contain no fluid. They are recognized by their opaque appearance.
On palpation, they feel firm and solid. Non-blisterform
lesions are also given descriptive names, depending on their
size and pattern. A non-blisterform lesion is either
a papule, nodule, tumor or plaque. |
A papule
is a lesion which consists of tissue and is less than
5 mm in its greatest diameter.
A nodule
is similar to a papule in that it consists of tissue, but
it is greater than 5 mm and less than 2 cm in its greatest
diameter.
A tumor
is similar to a nodule in that it consists of tissue, but it is
greater than 2 cm in its greatest diameter.
A plaque
is a slightly raised non-blisterform lesion which
has a broad flat top like a plateau. It has a "pasted
on" or "stuck on" appearance and is usually
greater than 5 mm in diameter. The elevation and
density of plaques vary. When the plaque is not as obviously raised
above the plane of the normal mucosa, or not as dense,
it will be more difficult to interpret as a "plaque".
| A papule, nodule, and tumor may be classified
as sessile or pedunculated according to their base or attachment
to the mucosa. |
A sessile
lesion is a papule, nodule, or tumor whose base or attachment
to the normal mucosa is the greatest diameter of the lesion.
A pedunculated
lesion is a papule, nodule, or tumor that has an attachment
to the normal oral mucosa which is smaller than the greatest
diameter of the lesion. In other words, the lesion is attached
by a stalk or pedicle.
The size of a lesion is often a clue
to its diagnosis. It is not necessary to measure exactly the size
of a lesion. Only a reasonably accurate estimate of the lesion's
size is expected. Size of lesions is best estimated
by comparing the lesion with familiar landmarks of known size
immediately adjacent to it. These landmarks include teeth, parotid
papillae, lingual papillae, incisive papillae, etc.
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example, lower incisor teeth are approximately 5 mm
in their greatest width and upper central incisors, 8-9 mm in
their greatest width. Molars are approximately 10 mm or 1 cm
in their mesiodistal aspect. The lingual filiform and fungiform
papillae are less than 1 mm in diameter. |
You will recall that more than one lesion
of a particular morphology is considered multiple. Multiple
lesions with any of the morphologic characteristics so far described
can be separate or coalescing. However, in the oral cavity,
small lesions coalesce more frequently than large ones.
Separate
lesions are usually few in number and relatively
widely spaced, but not always. They usually remain individual,
distinct lesions, even if they tend to enlarge after their initial
appearance.
Coalescing
lesions are numerous and in proximity to one another. Their
margins may merge and leave a single lesion, even if they enlarge
only slightly after their initial appearance.
With multiple lesions that vary in size, the morphology
of peripheral lesions becomes important in deciding whether the
lesions should be classified as separate or coalescing.
Whenever both separate and coalescing lesions are present,
the predominant type of lesion determines the correct morphologic
classification. If neither separate nor coalescing lesions is
predominant, it may be described as either.
DEPRESSED LESIONS
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A depressed
lesion is one in which the surface is below the normal
plane of the mucosa.
- Most depressed lesions are ulcers. An ulcer is a loss in continuity
of the oral epithelium. Clinically, the center
of the ulcer is often yellow to grey with
a red periphery. Occasionally, a red center may be observed.
Ulcers often result from the rupture of elevated lesions
such as vesicle, bullae, pustules, and papules.
- Some depressed lesions are the result of atrophy or scarring
and have an intact epithelial surface.
- Other depressed lesions may.be pits or blind "pouches"
caused by a failure of complete filling out during embryologic
development.
- Clinically, it is quite easy to determine if a lesion
is depressed by looking at the lesion from different angles
and relying on stereoscopic vision.
- Depressed lesions may be single or multiple.
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A single depressed lesion is one lesion
of a particular morphology. Where more than one lesion
of a particular morphology is present, they are multiple.
Since descriptors of single and multiple lesions vary slightly,
single lesions will be considered first.
Single
depressed lesions
Outline
- regular
- if the border is a continuous linear outline and
resembles a circle or an oval.
- irregular
- if the border has numerous deviations from a circular or
oval pattern
Margin
- Raised
- margin is above the plane of the normal mucosa.
- Smooth
- margin is on the same plane as the normal mucosa.
Depth - distance from the base of the ulcer to the plane
of margin
Multiple depressed lesions
have the same morphologic descriptors as discussed for single
lesions: Outline, margin, depth, and diameter.In addition, multiple
lesions may be either separate or coalescing.
- Separate lesions - few in number or widely spaced, not
likely to merge or blend into one another, even if they enlarge.
They remain distinct.
- Coalescing lesions - numerous and in proximity, may merge
or blend into one another after minor enlargement. When this occurs,
a single lesion is formed. The original outline of the initial
lesions may or may not still be detectable.
- If both separate and coalescing lesions are present,
the predominant type of lesion determines the correct morphologic
classification. In this case, the lesions are best described as
coalescing. If neither separate nor coalescing lesions are predominant,
it may be described as either.
FLAT LESIONS
| A flat lesion is one in which the surface
is on the same plane as the normal oral mucosa. Because of this,
any lesion of normal mucosal coloring would be undetectable
(except on the dorsum of the tongue). Therefore, the only way
most flat lesions can be detected is through a change in color. |
A flat lesion with an abnormal color is
called a macule.
Although color is a primary characteristic of macules, color will
be the subject of another unit.
Since the tongue is anatomically unique,
special considerations must be given to flat lesions occurring on
the dorsal and lateral borders of the tongue.
Loss of papillae results in an apparent depressed lesion,
but since the mucosal surface is intact, it is in fact a flat
lesion. Since it does not involve an abnormality of color, however,
it is not a macule. What you have to understand is that lesions
of the tongue that involve loss of papillae are exceptions, the
only flat lesions that are not macules.
Lesions resulting from a loss of papillae may be single
or multiple.
- Single
and multiple lesions may be regular or irregular in outline.
- Multiple
lesions are often irregular.
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