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ARTEFACTS IN CYTOLOGY
CELL LYSIS DUE TO ULTRASOUND GEL
Molyneux & Coghill (1994) Cytopath 5:41-45.
3 main categories of artefact:
1. Those found in cells exposed to extreme, unusual or
inappropriate physical conditions eg nuclear crush artefact
which is due to shear stresses on cells during specimen
collection and preparation.
2. Stain precipitate or deterioration of mountant.
3. Contamination of specimen eg blood or bacterial
overgrowth.
4. Contamination by ultrasound gel, possibly caused by an
osmotic effect. Causes:
(a) Heavy contamination will cause widespread cell lysis
in an inadequate sample.
(b) Lesser contamination may produce more subtle
cytological changes including cell swelling.
(c) Possible confusion with calcium salts or necrosis.
PLATELETS MIMICKING MICROORGANISMS
Abramczuk & Lachman (1995) Cytopathology 6: 419-425.
Platelets appear as small clusters of amphophilic round, oval
or slightly polygonal granules each measuring 1-2um in
diameter. Usually a narrow clearing around each granule.
Presence of platelets tend to coincide with the presence of
erythrocytes.
Phagocytosis of platelets by histiocytes, appearing as
intracytoplasmic inclusions, as well as platelets lying free
on the slide, can be confused with fungal spores or protozoa.
Suggest that silver and PAS stains for fungi will be negative.
PLANT CELL CONTAMINANTS IN PAP SMEARS
Ng & Reagan Tutorials in Cytology Slide set No.
Large cells (approx 80um in greatest dimension), with a dense
outer ectoplasmic zone and an inner lighter staining
endoplasm. Poorly defined laminations occur in the outer zone.
In the centre of the cell there is an amorphous reddish-brown
mass which cannot be identified as a nucleus.
Such cells have been found in vaginal lubricant which is
sometimes used to lubricate the the vaginal speculum. This
lubricant often contains gum guar.
CYTOCENTRIFUGE CARD FIBERS
Loughman & Scott (1987) Acta Cytolog 31(5):640-641.
Cytocentrifuge card fibers can be mistaken for urinary casts,
particularly hyaline and granular casts. The fibers vary in
size (12-120um) and is comparable to those possible for narrow
and broad casts.
Regular internal slit-like pores may be seen over the length
of the fiber.
Debris enmeshed in and adherent to these fibers may lead one
to suspect a granular caste.
The fibers often have a crenated edge and/or ragged ends.
Staining is variable, occasionally basophilic or acidophilic.
VEGETABLE CELL CONTAMINANTS
Weaver etal (1981) Acta Cytolog 25(3):210-214.
Cells of plant and animals are basically the same in that they
are both composed of nuclei and cytoplasm. It is in and around
the cytoplasm that thew more striking differences between
plant and animal cells can be found. Structures such as
mitochria, endoplasmic reticulum and golgi apparatus are
common to both. Plant cells contain cell walls, plastids and
starch grains, that are not found in animal cells.
Cell walls contain pectin compounds and cellulose fibers. They
may or may not be stained by the PAP stain, but their
appearance is revealed by their refractile appearance.
Plastids are cytoplasmic structures that have limiting
membranes. Some contain pigment, eg chloroplasts while many do
not being sites of manufacture and storage.
Starch can accumulate as grains and can be so numerous that
they occupy most of the cell.
Distinguishing features of vegetable cells:
* Presence of cell walls,
* Presence of storage vacuoles,
* Extraordinary large size,
* Quadrangular shapes,
* Regular spacial arrangement,
* A variety of colours irregularly distributed throughout
the cytoplasm,
* Hyperrefractile appearance,
* Overall alien appearance.
Green Bean: Resemble sheets of squamous metaplastic cells,
Walls identified as conspicuous, translucent boundaries to
the cells.
Navy Bean: Resemble a virocyte of molluscum contagiosum,
Is a storage cell for starch.
Carrot: Spiral vessels, called trachea, resemble
nematodes,
Are tubular remains of cells juxtaposed end to end that
have lost their intracellular contents.
Tomato: Resemble adenocarcinoma cells with mucin
distended cytoplasm,
Demonstrates the extremely large size that may be attained
by vegetable cells.
Asparagus: Have Indian file arrangement, similar to
metastatic lobular carcinoma.
Have distinctive quadrangular shapes.
Green Pea: Mistaken for virocytes of measles or herpes.
Peanut Butter: Mistaken for Cryptococcus,
Has refractile appearance.
Mushroom: Difficult to distinguish from Actinomyces or
Aspergillus.
Believe that plant nuclei are small and of little concern.
The darkly stained cytoplasm of plant cells can be mistaken
for large hyperchromatic nuclei and plant cell nuclei for
macronucleoli.
Last Updated on 9/11/05 by Tony Henwood.