There are no diseases, only sick people'

1
There are no diseases, only sick people.

• It was a French clinician who said,
• Il ny a pas des maladies, seulement les
  malades. (translation above)

2
What the Dentist Needs to Know about
Histopathology

• Dentists sometimes are erroneously inclined to
  consider the pathologists diagnosis as final and
  therefore immutable.
• The ultimate establishment of the diagnosis
  sometimes requires more than just the examination
  of a very thin slice of tissue through a series
  of lenses that magnify the tissues several
  hundred times.
• The process of diagnosing a biopsy specimen and
  deciding whether it is benign or malignant is
  not an exact science.
• Pathologists, in spite of the aura of
  infallibility with which they sometimes are
  regarded by their clinical colleagues, do make
  mistakes in diagnosis, and clinicians should
  remember that.

3
Pathologists Are Human and Therefore Fallible

• In general, the more experienced the pathologist,
  the greater the likelihood that he/she will be
  accurate in diagnosis.
• Important corollary Oral pathologists should be
  dentists first and histopathologic experts
  second. They can serve you and your patients
  best if you communicate with them and provide
  them with adequate clinical data.

4
Histologic Technique (and therefore
Histopathology) is not an Exact Science

• With present methods, it is not practically
  feasible to study living cells from a patient to
  establish a positive diagnosis while those cells
  are still alive.
• Preparation of tissue for examination must either
  freeze or coagulate the tissue with chemicals,
  producing a variety of artifacts.
• Technologists who prepare such specimens for
  require extreme skill in the traditional methods
  of making stained slices of these tissues and
  pathologists have become quite adept in
  interpreting such sections microscopically.

5
Histopathology is not an Exact Science

• Not all histotechnologists are equally skillful.
  Grievous errors can occur including incorrect
  identification of the specimen with the proper
  patient and failure to properly embed the one
  diagnostic bit of tissue out of several
  submitted, so that the pathologist never sees it.
• The best possible histologic techniques cannot
  provide an adequate specimen for diagnosis if the
  biopsy technique is poor or if the sample of
  tissue selected fails to include the diagnostic
  part of the lesion.
• Pressure, thermal, or cryogenic injuries to the
  tissues during the biopsy may prevent proper
  histologic diagnoses.
• Routine histologic technique only produces a
  two-dimensional sample to be studied by the light
  microscope. Many pathologists and clinicians
  fail to think of the lesion in three dimensions
  and even more importantly in terms of the fourth
  dimension time.

6
Important corollaries

• If the histopathologic diagnosis on a given
  patient does not fit with all the other facts,
  first double check with the pathologist to be
  sure that the specimen examined under the
  microscope actually came from your patient.
• Get (or become) an expert in the technique of
  biopsy.
• Be sure that that you and your staff has properly
  labeled that specimen and completed all paperwork
  properly.

7
Important corollaries

• Examination of a microscopic slide is similar to
  looking at a single frame of a movie. It may be
  possible to deduce from the single still picture
  much of what the earlier pictures might have
  looked like, but one can only guess at the way
  the plot (or disease process) may develop
  subsequently.
• Pathologists are not omniscient and you should
  not expect them to be able to predict accurately
  what will happen in any patient. For example, if
  a pathologist makes a diagnosis of reactive
  hyperplasia on a lymph node and the patient
  subsequently develops a nodular malignant
  lymphoma, you should not necessarily assume that
  the first diagnosis was incorrect.

8
Dentists Frequently Become Trapped by Semantics

• Once the histopathologist diagnosis or label is
  written on a patients record, that individual
  tends to be looked upon henceforth as having that
  specific disease.
• Diseases are subject to all the complexities of
  that host including genetic and environmental
  (both internal and external) influences.
• Disease may be modified by changes in a variety
  of host factors
• Important corollary The only true disease
  entity is the disease process in the individual
  patient.

9
Histologic Appearance May Vary from Place to
Place within any Lesion

• It can be hazardous and misleading to predict
  biologic behavior on the basis of limited
  histologic samples.
• Samples from necrotic areas are almost always
  impossible to interpret microscopically.
• Important corollary Whenever the nature of a of
  disease suggests that a variety of forms may be
  present, the pathologist must take sufficient
  samples.

10
Some Lesion Appear to be Malignant Histologically
but are Benign Biologically

• Histopathologists cannot always equate anaplastic
  and polyploid cells with/without increased
  mitotic activity with a diagnosis of a malignant
  tumor.
• Important corollary Some lesions appear to be
  benign histologically but are malignant
  biologically.

11
Virtually Identical Histologic Patterns May
Represent Totally Different Diseases

• Many pathologists have learned to recognize the
  histologic pictures they see through the
  microscope and to identify them with specific
  labels.
• Occasionally they forget, or are unaware, that
  similar pictures may represent quite different
  disease processes.
• Such possibilities of misinterpretation must be
  considered and avoided.

12
Virtually Identical Histologic Patterns May
Represent Totally Different Diseases

• Important corollary Diagnosis should not be a
  guessing game when patients lives are at
  stake. Be sure that you share all the data
  (including historic, laboratory, and
  roentgenographic) with the pathologist.

13
Most Important Corollaries

• Never accept a written report of histopathologic
  diagnosis as unequivocal, especially when the
  pathologic diagnosis does not fit with the other
  clinical data.
• Histopathologic diagnoses should be considered as
  other laboratory values and the primary data (the
  microscopic sections) should be reviewed whenever
  the interpretation varies from the other clinical
  aspects of the case.
• If you not comfortable with a diagnosis, do not
  hesitate to request a consultation with the
  pathologist.
• If all the facts still fail to fit the clinical
  disease as expressed in the unique individual
  patient, another biopsy should be performed.

14
Orofacial Histology and Embryology
15
Slide 148. Lip of newbornsagittal section X 2.2
16
Slide 149. Skin of lipsagittal section X 8
17
Slide 150. Red margin of lipsagittal section X 8
18
Slide 151. Cheek epithelium X 20
19
Slide 145. Oral mucosa (lip)sagittal section X 8
20
Slide 152. Submucosa of lip X 63
21
Slide 147. Transition between gingiva and
alveolar mucosalongitudinal labiolingual section
X 25
22
Slide 153. Gingival epitheliumlongitudinal
labiolingual section X 63
23
Slide 143. Dentogingival junction after eruption
(monkey deciduous molar)coronal section X 16
24
Slide 160. Specialized mucosa, filiform
papillaecoromal section X 25
25
Slide 7. Human embryonic head (30 mm C-R, 8 wks
c.a.)-coronal section X 6
26
Slide 30. Early dental lamina of molar
regioncoronal section X 63
27
Slide 32. Early cap stage of maxillary molar
tooth germ regioncoronal section X 20
28
Slide 33. Bell stage of maxillary incisor tooth
germsagittal section X 8
29
Slide 34. Mitosis in bell stage of enamel organ
of maxillary incisor--sagittal section X 80
30
Slide 37. Deposition of dentin and enamel matrix
(maxillary incisor tooth germ, early apposition
stage)sagittal section X 50
31
Epithelial Pathology
32
Slide 151. Normal cheek epithelium X 20
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
33
Hard palatal mucosa (11.2 )
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
34
Mucosa of lower lip (11.1)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
35
Buccal mucosa (11.3)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
36
Thickened oral epithelium (acanthosis) (11.24)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
37
Hard palatal mucosa (11.4)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
38
Chronic hyperplastic candidiasis parakeratosis,
acanthosis, epithelial cell atypia and chronic
mucositis (11.18)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
39
Buccal mucosa (11.12)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
40
Buccal mucosa (11.10)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
41
Buccal mucosa (11.9)
42
Buccal mucosa (11.37)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
43
Buccal mucosa (11.80)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
44
Labial mucosa (11.82)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
45
Mucobuccal fold (11.77)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
46
Labial mucosa (11.79)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
47
Buccal mucosa (11.84)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
48
Labial mucosa (11.81)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
49
Buccal mucosa (11.7)
normal
?
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
50
Buccal mucosa (11.6)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
51
Buccal mucosa carcinoma in situ
Top-to-bottom dysplasia
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
52
Lateral border of tongue (11.31)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
53
Lateral border of tongue (11.30)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975
54
Dorsolateral tongue (11.72)
Marsland EA, Browne, RM. Colour Atlas of Oral
Histopathology. Chicago. Yearbook Medical
Publishing. 1975