7/27/2010 1 RESPIRATORY CYTOLOGY ML 301 Cytology Dr Pritinesh Singh Department of Pathology School of Health Sciences Fiji School of Medicine Course Objectives • Appreciate the anatomy, histology and cytology of the respiratory system. • Describe the pathology and cytology of benign respiratory conditions evaluated on benign respiratory conditions evaluated on sputum and FNA specimens. • Distinguish between the different malignant conditions seen in the respiratory system and the appearance of this in smears THE RESPIRATORY SYSTEM CELLULAR COMPONENTS OF THE RESPIRATORY SYSTEM Introduction • Respiratory cytology consists of 3 basic types of exfoliative specimens – Sputum, bronchial cytology (including washings & brushings) and bronchoalveolar lavage (BAL) • In general large central tumors are more readily detected by exfoliative methods then small peripheral ones exfoliative methods then small peripheral ones • Squamous & Small cell carcinomas are more accurately diagnosed then adenocarcinomas • Poorly differentiated cancers are more easily detected then well differentiated ones • Benign tumors may not shed any diagnostic cells • Most diagnostic problems relate to sampling (false negative) & inflammation (false positive)
Transcript
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RESPIRATORY CYTOLOGY
ML 301 Cytology Dr Pritinesh Singh
Department of PathologySchool of Health Sciences
Fiji School of Medicine
Course Objectives
• Appreciate the anatomy, histology and cytology of the respiratory system.
• Describe the pathology and cytology of benign respiratory conditions evaluated onbenign respiratory conditions evaluated on sputum and FNA specimens.
• Distinguish between the different malignant conditions seen in the respiratory system and the appearance of this in smears
THE RESPIRATORY SYSTEM
CELLULAR COMPONENTS OF THE RESPIRATORY SYSTEM
Introduction• Respiratory cytology consists of 3 basic types of exfoliative
specimens– Sputum, bronchial cytology (including washings & brushings) and
bronchoalveolar lavage (BAL)• In general large central tumors are more readily detected by
exfoliative methods then small peripheral onesexfoliative methods then small peripheral ones• Squamous & Small cell carcinomas are more accurately
diagnosed then adenocarcinomas• Poorly differentiated cancers are more easily detected then
well differentiated ones• Benign tumors may not shed any diagnostic cells• Most diagnostic problems relate to sampling (false negative)
& inflammation (false positive)
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SPUTUM• Composed predominantly of mucus but also contains
cells & other elements• Significant spontaneous sputum production indicates the
presence of pulmonary disease• Most smokers & patients with bronchogenic carcinoma p g
have a cough & can produce sputum• Sputum production can also be induced• Sputum screening unable to prevent lung cancer in the
way pap smear has prevented cervical cancer• Most readily accessible pulmonary cytology specimen,
cannot be used to localize lesion
SPUTUM• To look for cancer in spontaneous sputum specimens, its
best to examine pooled morning secretion.• At least 3 specimens should be submitted to diagnose
cancer, single specimen is unreliable in tumor detection• Fresh specimens are preferred• It can be preserved in alcohol but is not recommended• It can be preserved in alcohol but is not recommended
as it can shrink the cells making them difficult to interpret• It can fail to penetrate the mucus, leaving embedded
cells poorly fixed & can make smearing difficult because it coagulates the mucus
SPUTUM• Specimens can be prepared by the
Saccomanno (blender) technique or by the “pick and smear” technique– Advantage of Saccomanno
• is that it concentrates cells, increasing diagnostic yieldDi d t i l d– Disadvantages include:
• fragmentation of fungal organisms, disruption of glands, dispersion of cells of small cell carcinoma & creation of potentially infectious aerosols
• Post bronchoscopy sputum has the highest sensitivity of any exfoliative respiratory cytology specimen.
BRONCHIAL CYTOLOGY– Patients with abnormal sputum cytology
should undergo bronchoscopy– Bronchial cytology including bronchial
washings and brushings is better suited for diagnosis of peripheral lung lesions thandiagnosis of peripheral lung lesions than sputum cytology
– Bronchoscopy is also useful in diagnosing patients with central lesions & negative sputum cytology who are not candidates for surgery
BRONCHOALVEOLAR LAVAGE
• Often used to diagnose opportunistic infections in immuno-compromised hosts (AIDS or transplants)
• Helpful in diagnosis of interstitial lung disease, granulomatous disease includign sarcoid, hypersensitivity pneumonia, drug induced pulmonary toxicity, asbestosis, pulmonary hemorrhage & cancer (particularly when peripherally located)
• It’s important to look for fungus, Pnuemocystis, viral changes, hemosiderin laden macrophages & malignant cells; some specimen should also be cultured
• Can help separate inflammatory processes in which lymphocytes predominate (eg. Sarcoid, hypersensitivity pneumonia including drug reaction, berylliosis) from those in which neutrophils or macrophages predominate (eg pneumonia, idiopathic pulmonary fibrosis, cytotoxic drug reaction, Langerhans histiocytosis)
• Haemosiderin laden macrophages suggest pulmonary hemorrhage but also can be seen in infection & cancer.
THE CELLS• Cells obtained in bronchial washings & brushings are
better preserved than those in sputum• Cells from squamous cell carcinoma in sputum are
usually keratinized (differentiated) than those found in bronchial washing or brushing specimens of the same ttumor
• All cell types of bronchogenic carcinoma tend to appear less mature in bronchial brush specimens
• Although single tumor cells are an important feature of malignancy, occasionally they are not present in bronchial brushing specimens of malignant tumors.
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SQUAMOUS CELLS• Most squamous cells come from the mouth as
contaminants• Cytologic appearance is similar to those in the pap
smear with a predominance of superficial cells• Anucleate squames & intermediate cells may also be
presentpresent• Benign pearls & occasional spindle squamous cells may
be seen• Reactive/ degenerative changes are common• Squamous cells originating in the mouth often show
cytologic atypia that can cause diagnostic problems
Pearl Squamous cells
Glandular Cells
• Tracheobronchial tree is lined by pseudostratified glandular epithelium composed predominantly of ciliated columnar & mucous goblet cells, normally in a ratio of at least 5:1
• Other cell types include Clara cells, reserve cells & Kulchitsky cells. Lymphoid cells are present in the walls of the bronchi (bronchial associated lymphoid tissue, BALT)
Ciliated columnar cells• Most characteristic feature of ciliated cells is presence of
cilia on the apical surface, anchored into a terminal bar• At the other end the cells have a cytoplasmic tail by
which they attach to the basement membrane• Cytoplasm is basophilic & homogenous with basally y p p g y
oriented, round to oval nuclei.• Chromatin ranges from fine – mildly coarse – dark• Small nucleoli may be present• Ciliary tufts become detached from cells as a non
specific reaction to injury.
Ciliated columnar cells -bronchial
Mucous Goblet Cells• Degenerate rapidly in sputum• Commonly seen in bronchial cytology• Have abundant, vacoulated cytoplasm, filled with
mucin• Nuclei are uniform & basally located• Are numerous in asthma, chronic bronchitis,
bronchiectasis & allergic conditions• When in abundance, consider mucinous
• Can include nuclear enlargement & pleomorphism with abnormally coarse dark chromatin & prominent nucleoli
• Multinucleation is common• Reactive changes seen more in bronchial thanReactive changes seen more in bronchial than
sputum cytology• In contrast with cancer, benign cells have good
intercellular cohesion with fewer single cells• There is a range of atypia in benign conditions,
whereas in malignant neoplasms there is usually a discrete population of abnormal cells
Reactive bronchial cells showing markednuclear size variation. Note the cilia is
retained evidence of their benign nature
Reparative/ Regenerative Bronchial Cells
• Similar to that seen in the pap smear• Atypia can range from mild – severe, mimicking cancer• Repair is characterized by cohesive, orderly, flat sheets of
cells with adequate cytoplasm, single cells are absent or rare• Although nuclei can be enlarged & pleomorphic with large or
irregular nucleoli the nuclei are not significantly crowded orirregular nucleoli, the nuclei are not significantly crowded or disorderly & the NC ratio remain WNL.
• Chromatin is fine but nuclei can degenerate, undergoing karyopyknosis, karyorrhexis or karyolysis
• Cancer is characterised by crowded disorderly groups & single atypical cells with hyperchromatic coarse chromatin.
Reactive bronchial cells
Pneumocytes• Alveoli are lined by 2 kinds of pneumocytes:
Type I & Type II• Type I alveolar pneumocytes are flat cells
(squamous) & cover > 90% of the alveolar surface. Not recognized in cytologic specimensg y g p
• Type II granular pnuemocytes are columnar cells that are normally found scattered in the alveoli & secrete surfactant, usually recognized when they are hyperplastic (reactive)
• ↑ NC ratio, angular membranes, chromatin clumping or clearing, macronucleoli & can be
Type II Reactive Pneumocytes
multinucleated• Primary DDX is with
adenocarcinoma (BAC)
BAC is characterised by the presence of numerous well preserved tumor cellsWhile reactive are fewer & may be degenerated. Benign groups have scalloped borders & less dept of focus. Cilia if present point to benign diagnosis
Alveolar Macrophages• Bone marrow derived histiocytes found in free
alveolar space• Presence is necessary but not sufficient
condition for adequacy of sputum specimen• Indicate that some of the peripheral, alveolarIndicate that some of the peripheral, alveolar
part has been sampled.• Ciliated respiratory cells are insufficient
evidence of deep lung sample in sputum• In BAL alveolar macrophages should be
abundant
• Identical to other histiocytes• Vary in size• Have round – oval – bean shaped nuclei• May be mono – bi – multi nucleated• Giant cell histiocytes mainly found in granulomatous
di h id & TB
Alveolar Macrophages
diseases such as sarcoid & TB• Chromatin has salt & pepper texture• One or more nucleoli may be present• Cytoplasm is foamy & stains variably• Cells are phagocytic & contain various particles such as
carbon• Cells named according to particles found in them
• Carbon histocytes– Common in smokers & urban dwellers– Known as “dust cells” and contain black carbon pigment
• Siderophages– Occur in reaction to bleeding, contain blood pigment hemosiderin.– Presence usually indicates old bleeding associated with benign
conditions such as infarcts heart failure & hemosiderosis or with
Alveolar Macrophages
conditions such as infarcts, heart failure, & hemosiderosis or with malignant conditions
• Lipophages– Have lacy bubbly cytoplasm due to lipid content. Lipid source can be
endogenous (tissue destruction) or exogenous (nasal drops)– Can be seen in conditions such as lipid pneumonia, fat embolism,
acute pancreatitis. In children may be associated with aspiration pneumonia
– When present particularly in adults, malignant conditions must be considered.
BAL – Alveolar macrophages
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BAL – Dust macrophages Siderophages
Acellular Material Curschmann’s spiral
• Found in conditions with excess mucus production eg asthma & smoking
• Formation due to intrinsic property of mucus
• Have dark stained centerHave dark stained center with lighter stained periphery & usually spiral like a corkscrew
• Maybe associated with eosinophils or neutrophils
Ferriginous Bodies• Form when iron salts
precipitated onto tiny rounded or fibrous inhaled dust
• Fiber is often asbestos but can be other particles peg fiberglass, carbon, or other minerals
• Typically golden brown, beaded and have bulbous tips. Frequently engulfed by macrophages.
Charcot – Leyden Crystals• Bi-pyramidal or needle
like red crystals composed of condensed granules derived from eosinophils.
• Eosinophils are usually p ypresent near the crystals
• Are particularly associated with asthma but can occur in other allergic reactions
Other acellular material
• Alvelolar proteinosis – due to enzymatic disorder of macrophages, results in coarsely granular, periodic acid – schiff (PAS) – positive debris.
• Amyloid is dense, acellular, waxy material that has a characteristic “apple green” birefringence under polarized light after congo red staining.
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• Corpora amylacea are concentrically laminated, non-calcified, alveolar casts associated with preceding pulmonary edema
Psammoma bodies are concentrically laminated, calcified bodies associated with BAC but can also be seen in benign disease (eg TB or microlithiasis)
Contaminants• Food particles –
common in sputum and source of diagnostic error.
• Meat is recognized by• Meat is recognized by cross striations.
Starch – from glove powder typically has a cracked center & a maltese cross polarization
Pollen – appears as colorful bodies with cell walls and spikes
Benign Proliferation• The bronchial epithelium can undergo a series
of transformations including reserve cell hyperplasia, squamous metaplasia & bronchial hyperplasia in response to a variety of chronic irritations or inflammations ranging from airirritations or inflammations ranging from air pollution to infections to cancer
• Squamous epithelium is more mechanically resistant but less specialized than the respiratory epithelium
• Not premalignant, squamous metaplasia is the mileu in which cancer may arise
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Reserve Cell Hyperplasia• Most commonly observed in bronchial brush specimens• Exfoliates as tightly cohesive groups of small uniform
cells, often lined on one surface by ciliated columnar cells
• Individual reserve cells resemble l h t /hi ti tlymphocytes/histiocytes
• Have small dark round nuclei with a thin rim of basophilic cytoplasm & high NC ratio
• Nuclei may show some molding• Nucleoli are usually absent unless cells are irritated• Background is clean• Dif Dx: small cell carcinoma (nuclear pleomorphism,
nuclear molding, crush artifact, tumor diathesis)
Reserve Cell hyperplasia
Squamous Metaplasia• Essentially normal & ranges from focal – extensive• Frequently associated with reserve cell hyperplasia• Can be similar to that seen in pap smear with rounded
parabasal sized cells.• When immature has smaller cells with angulated, polygonal
outlinesoutlines• Cells appear in a loose cobblestone sheet• Metaplastic cytoplasm is dense with distinct cell borders &
usually stains cyanophilic (blue-green)• Nuclei round with granular chromatin, nucleoli present when
cell is irritated• Degenerative changes include cytoplasmic eosinophilia or
orangeophilia & nuclear karyorrhexis or pyknosis. (May be difficult to distinguish from parakeratosis)
Parakeratosis & Atypical Parakeratosis
• Similar to that of pap smear• Usually results from severe irritation• Atypical parakeratosis can occur with
squamous cell dysplasia or carcinomasquamous cell dysplasia or carcinoma– Is also known as pleomorphic parakeratosis
mimicking keratinizing squamous cell carcinoma
– Look for clear-cut malignant cells to diagnose cancer
Atypical Parakeratotic cells Therapeutic Agents• Radiation & Chemotherapy can induce severe
cytologic atypia which can mimic cancer• Clinical history is essential in diagnosis.RADIATION• Induces changes that are characterized by
cytomegaly of squamous or glandular cells• Irradiated malignant cells show characterized
malignant cells plus radiation effect• These induced changes may subside with time
or persist for life
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Radiation Effect• On squamous cells causes enlargement of
cytoplasm and nucleus so the NC ratio remains WNL
• Multinucleation is commonN l i b h /h h ti &• Nuclei may be hyper/hypochromatic & sometimes vacuolated
• Prominent nucleoli or macronucleoli may be seen
• Cytoplasm is thick & dense, vacoulated & polychromatic
Chemotherapy• Similar changes to that of radiation• Cells are enlarged, pleomorphic and have large
nuclei with dark chromatin and prominent nucleoliMit ti fi b• Mitotic figures can be seen
• Can be an increase in mucin and goblet cells• Histiocytes and inflammatory cells are frequently
seen in the background• Atypical cells tend to be few, degenerated and
• Can be seen in TB, fungus, or other infections; rheumatoid arthritis, sarcoid & as a reaction to cancer
• Granulomas are nodular collections of epitheloid histiocytes
• Epitheloid histiocytes are found in loose syncytial aggregatesaggregates
• The nuclei are usually elongated and have folded nuclear membranes, fine pale chromatin & tiny nucleoli. Cytoplasm is more abundant, eccentrically located around the nucleus & has fibrillar quality with poorly defined cell borders.
• In foreign body granulomas, phagocytosis is more prominent.
Tuberculosis
• Epitheliod histiocytes, giant cells, lymphocytes and a necrotic background
• Acute inflammation can be seen in early course of disease
• Identification of beaded, red AFB or +ve culture clinches the diagnosis
• Reactive atypia of bronchial or squamous metaplasia cells or alveolar pneomocytes could result in a false +ve diagnosis.
SPUTUM - TB
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TB granuloma Sarcoid• Chronic granulomatous disease of unknown
aetiology• Non caseating granulomas• Schaumann bodies or asteroid bodies are
ti f idi isuggestive of sarcoidiosis• Schaumann bodies are concentrically laminated
calcifications found in the cytoplasm of giant cells
• Asteroid bodies are intracytoplasmic, radiate, crystalline arrays.
Rheumatoid Granuloma of Lung• Can exfoliate epitheloid histiocytes with bizarre
shapes• Have hyperchromatic, degenereated, smudged
nuclei with variably colored cytoplasm ranging from blue- red – orangeg
• Occasional multi-nucleated giant cells may be seen
• Bizarre cells can mimic keratinizing squamous cell carcinoma.
Viral Pneumonia
• Can cause reactive change in bronchial cells
• Have specific viral changes such as those due to cytomegalovirus or herpesdue to cytomegalovirus or herpes
• Atypical cells usually are sparse in infection while in BAC are numerous
HSV infection
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Other Infections
• Candida/ bacterial colonies –contamination or overgrowth
• Actinomyces – common saprophyte in tonsilstonsils
• Aspergillus, Pneumocystis – common in immunocompromised hosts
Pneumocystis carinii Pneumocystis carinii
Pneumocystis carinii (meth. silver)
Pneumocystis carinii (giemsa)
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Candida Aspergillosis
Aspergillosis Aspergillosis
Pulmonary Embolism/ Infarct• Solitary pulmonary embolism can mimic a neoplasm• Some cases exfoliate with markedly reactive cells• 3 D clusters of pleomorphic cells with enlarged nuclei,
irregular chromatin clearing & macronucleoli can mimic adenocarcinoma
• Blood, inflammation, siderophages may be seen in the background
• Squamous metaplasia is common• Clues to benign nature – sparsity of atypical cells,
variability within groups• Shallow depth of focus, tight cell grouping, presence of
