Histology Course Department of Pathology, University of Zurich Histology Course

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General Tumors      How to use the virtual microscope ICD-Code Scripts (German)
 
PROCEDURE WITH TUMORS
 
 
Diagnostics of tumors

Diagnostic procedure for the morphological diagnosis of tumors consists in principle always in the systematic search and evaluation of below-mentioned criteria. Clinical, laboratory and roentgenological examinations often result in localisation and a size approximation of a node or tumor. Precise diagnosis of the tumor - its morphology, grade of differentiation, dignity - has to be done on a cytological smear (fine needle aspiration cytology), instantaneous section (frozen section), paraffin section (needle biopsy, surgical biopsy) and/or on a surgical sample. The compostion of all findings is the base of the future therapy.
 

Criteria of histopathologic tumor diagnostics

Prerequisite
At a change you are detecting a "swell", a neoplasm of tissue and you are concluding due to differential diagnosis that the change is a tumor (see under 3rd point in "General Procedure", differential diagnosis). Now you are trying to ensure the diagnosis of a tumor and to characterise the tumor as exact as possible.
 

STEPWISE EVALUATION
 

 

Macroscopical criteria

- nodes ("neoplasia" = increased freshly built tissue)
- localisation
- size
- consistency
- capsule +/-
- adhesion with surrounding tissue and/or invasion
- cut surface
- homogenous/inhomogenous
- necrosis
- definition
- sharp
- diffuse (infiltration, invasion of the capsule)
Distinguish:
- infiltration without destruction (z.B. hemangioma)
- infiltration with destruction = invasion
 

Histological criteria

- Translation from the two-dimensiol section to the three-dimensional form (round lesion/node)
 

Loupe - Invasion and destruction of the surrounding parenchyma by the tumor
- capsule +/-
- capsule intact/broken
 
Low to medium magnification

- Atypia of tumor tissue (anaplasia)
- tissue architecture similar to a known tissue or no comparison to normal tissue possible
- solid tissue
- tubular glands: typical, regular/atypical, irregular, polymorphic
- papilla
- cellular strands
- cellular plates
- cell colonies
- no observable formation
- fibres irregular/bundled
- necroses
- stroma existing/missing, wide/narrow
 

Cytological criteria
 
 
High magnification

- Atypia of tumor cells (anaplasia)
- monomorphy/polymorphy of cells
- basophilic cytoplasm
- relation nucleus-plasm (normal 1:6 - 1:4) shifted in favour of nucleus (e.g. 1:1 or 2:1)
- monomorphy/polymorphy of nuclei
- hyperchromasia (polyploidy/aneuploidy)
- big, partially multiple nucleoli
- mitoses
       - number
       - typical/atypical shape
- reaction of surrounding tissue, inflammation
 

Strongest criteria for histological diagnosis of a malign tumor

1. Invasion and destruction of surrounding tissues with or without vascular invasion

2. Anaplasia (atypia, dysplasia) of tumor tissue = more or less abberance from known normal tissue
  3. Anaplasia (atypia, dysplasia) and polymorphia (pleomorphia) of tumor cells and tumor nuclei
  4. Metastasis: a metastasising tumor is malign by definition. But it is not often known, if a primary tumor has already metastasied. In such a situation you have to refer solely to criteria 1 - 3.
   
The mentioned criteria have to be systematically evaluated for each sample. They are not mentioned again at each sample with tumor tissue.
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