Ch. 2 - Respiratory Tract & Mediastinum Flashcards
What are the normal cells found in the trachea & bronchi?
Pseudostratified ciliated respiratory epithelium, goblet cells, reserve cells, and neuroendocrine (Kulchitsky) cells. Can also find smooth muscle, salivary gland…
What are the normal cells found in the terminal bronchioles
Nonciliated Clara cells (bland), Type I pneumocytes (paper thin), Type II pneumocytes (plump and cuboidal, vacuolated)
What are the strengths and weaknesses of sputum sampling?
Easy to obtain, but frequent contaminants from oral contents. Ideally should be collected multiple times (especially first in AM).
What role do bronchoalveolar lavages fulfill?
Useful for diagnosis of infections, especially opportunistic ones such as pneumocystis & mycobacteria.
What is the best indication for transbronchial aspiration (Wang needle method)?
Good for distinguishing small cell from NSCLC, staging of NSCLC.
How does EBUS compare to unguided transbronchial (Wang needle) aspiration?
Addition of ultrasound improves both sensitivity and specificity, and allows sampling of further/smaller lymph nodes.
What indications exist for percutaneous FNA of the mediastinum/lung? What are its major drawbacks?
For peripheral pulmonary masses. There are many contraindications and pneumothorax is extremely common (30%!).
What are some examples of targetable mutations in NSCLC?
EGFR, VEGF(?), BRAF, ALK, HER2(?).
What is the significance of reactive squamous cells in a BAL?
Probably represents oral contaminants.
Describe the morphology of reactive bronchial changes.
Enlarged nuclei with large nucleoli, occasional multinucleation. Occasional “Creola bodies” (large clusters).
What disease does bronchial reserve cell hyperplasia represent? How can it be distinguished?
SCLC (cohesive small cells with smudged chromatin and nuclear molding). Distinguished by absence of mitoses/apoptoses.
How can pneumocytes repair/hyperplasia be distinguished from carcinomas?
Can be difficult; clinical history is the best guide.
What are ferruginous bodies?
Dumbbell-shaped mineral fibers encrusted with ferroproteins, sometimes associated with asbestos exposure.
What are Curschmann spirals?
Coiled strands of mucin that stain dark purple. They are nonspecific, not even specific for asthma.
What are Charcot-Leyden crystals?
Rhomboid, orangeophilic structures derived from eosinophils in asthmatic patients.
In what conditions can psammoma bodies be seen?
- Papillary tumors (pulmonary adenocarcinoma, mesothelioma, metastatic thyroid & ovarian cancer)
- Pulmonary TB
- Alveolar microlithiasis
What are corpora amylacea?
Proteinaceous spherical structures of unknown composition; identical to those of prostate.
What does the presence of amorphous protein raise concern for?
Amyloidosis, PAP
What are the morphologic features of Measles/RSV?
Look for giant cell pneumonia with enormous multinucleated cells.
What are the morphologic features of adenovirus infection?
- Smudge cells (Basophilic inclusions filling entire nucleus)
- Cowdry-A like inclusions.
- Also look for ciliocytophthoria.
What role does FNA play in bacterial pneumonia?
Not useful for distinguishing infectious agents; only for ruling out underlying malignancy.
What are the FNA features of tuberculosis?
Granulomatous inflammation with epithelioid histiocytes and Langhans giant cells, often necrotic. Organisms visible with AFB stain.
What are the morphologic features of Cryptococcus?
Highly refractile yeast with thick mucinous capsule.
What are the morphologic features of Histoplasma?
Small yeast within macrophages with narrow-based budding, best visualized with silver stain.
What are the morphologic features of Blastomyces?
Broad-based budding large yeast with thick cell wall.
What are the morphologic features of Coccidioides?
Huge spherules with endospores.
What are the morphologic features of Paracoccidoides?
Large “mariner wheel” organism with overlying squamous metaplasia.
What are the morphologic features of Sporotrichosis?
Small intracellular yeast; quite hard to distinguish from Histoplasma.
What are the morphologic features of Aspergillosis?
45’-branching organisms with eosinophil and charcot-leyden crystals. May invade vessels. In cavitary lesions, fruiting bodies may be seen.
What are the morphologic features of Zygomycosis?
90’-branching organisms with aggressive vessel invasion and necrosis.
What are the morphologic features of Pneumocystis?
Masses of organisms enmeshed in proteinaceous foamy green material. Cysts appear as negative images, but intracystic bodies and trophozoites are distinct.
Describe the cytology of Sarcoidosis.
Noncaseating granulomas: Multinucleated giant cells, lymphocytes, and epithelioid histiocytes (reniform/boomerang nuclei)
Describe the cytology of Wegener granulomatosis
Neutrophils, giant cells, “pathergic” (necrotic) collagen, and epithelioid histiocytes.
Describe the cytology of Pulmonary amyloidosis.
Irregular waxy amorphous material with scalloped and cracked blue-green appearance. May also have giant cell reaction.
Describe the cytology of Pulmonary alveolar proteinosis.
Opaque, milky gross material with acellular eosinophilic blobs of PAS+ material, some within macrophages.
Describe the cytology of pulmonary hamartoma.
Mixture of mesenchymal (fibromyxoid, cartilaginous) and benign epithelial elements.
Describe the cytology of Inflammatory myofibroblastic tumor.
Spindle cells arranged in fascicles or storiform pattern, plus some polymorphous inflammatory cells.
What is the principal abnormality in IMT?
ALK rearrangements, usually t(2;5) ALK-NPM
Describe the cytology of granular cell tumor.
Small clusters of macrophage-like cells (Schwann cells) with abundant granular eosinophilic cytoplasm.
In lung cancer, what genetic abnormalities are induced by tobacco smoking?
3p deletion
p53 mutation
K-RAS mutation
P16 mutation
Describe the cytology of squamous cell carcinoma.
Well-differentiated: Cohesive with orangeophilia.
Poorly-differentiated: Cohesive clusters of cells with “school of fish” streaming, “potato surface” chromatin.
How is adenocarcinoma distinguished from squamous cell carcinoma?
Staining for TTF-1 (favors adeno), p40 (favors SQC, but does not trump TTF-1)
What are the 5 main histologic subtypes of lung adenocarcinoma?
Lepidic Acinar Solid Papillary Micropapillary
Describe the cytology of lung adenocarcinoma.
Sheets, balls, papillae, or scattered cells with well-defined borders and mucin vacuoles. Psammoma bodies can be seen in micropapillary.
How is lung adenocarcinoma distinguished from mesothelioma?
Immunostaining (complex, later chapter)
Mesothelial cells are distinguished by slitlike “windows” separating cells.
Describe the cytology of Large cell carcinoma.
Large, syncytial clusters with irregular nuclei, chromatin clearing and often prominent nucleoli.
What are some variants of LCNEC?
Basaloid, lymphoepithelioma-like, clear cell, with rhabdoid phenotype, and large cell neuroendocrine.
What are some subtypes of sarcomatoid carcinoma?
Pleomorphic carcinoma Spindle cell carcinoma Giant cell carcinoma Pulmonary blastoma Carcinosarcoma
Describe the cytology of pulmonary blastoma.
A spindle cell component (myxoid, chondroid, osteoid, or rhabdomyoblastic) and an epithelial component (“piano key”-like endometrioid morphology).
How are carcinoid, atypical carcinoid, large cell and small cell carcinomas distinguished?
Morphology, mitotic rate, MIB-1.
Describe the cytology of carcinoid tumor.
Loosely cohesive groups of uniform cells in rosette-like structures. Salt & pepper chromatin and no nucleoli.
Describe the cytology of atypical carcinoid.
Loosely cohesive rosettes with occasional mitoses, some prominent nucleoli, even some necrosis.
Describe the cytology of small cell carcinoma.
Small cells with scant cytoplasm, crush artifact, many mitoses and necrosis. Also look for paranuclear blue bodies.
Describe the cytology of adenoid cystic carcinoma. What is the genetic abnormality?
Cylinders or spheres of innocuous epithelial cells surrounding basal lamina material. t(6;9) MYB-NFIB
Describe the cytology of mucoepidermoid carcinoma. What is the genetic abnormality?
Squamous, intermediate, and mucinous cells. t(11;19) MECT1-MAML2
Describe the cytology of clear cell “sugar” tumor. How does it stain?
Bland polygonal and spindle cells with glycogen-rich cytoplasm. Stains for melanocyte markers but not keratins (PEComa).
Describe the cytology of sarcomas.
Sheet-like cellular aggregates of highly atypical cells. Beyond that depends on the sarcoma.
What lymphomas are often seen in lung?
EMZL, DLBCL, lymphomatoid granulomatosis, PTCL. Primary CHL is uncommon.
What metastases should be considered in lung?
Colon, melanoma, breast, renal, thyroid.
What is the staining pattern of thymoma?
Epithelial cells stain for CK5 and p63.
Lymphocytes stain for CD99, CD3, TdT.
Distinguish between type A and type B thymoma.
Type A thymoma are spindled or ovoid with Hassall corpuscles. Type B are predominantly round or polygonal with varying degrees of lymphocyte infiltration.
Describe thymic carcinoma.
Obviously malignant cells that stain for CD5 and CD117. TTF-1 negative.
What lymphomas are found in the mediastinum?
CHL
PMBL
T-LBL
What germ cell tumors can be seen in the mediastinum?
Teratoma
Seminoma
Nonseminomatous germ cell tumors
Describe the cytology of seminoma.
Hypercellular loose clusters of round cells with coarse chromatin with abundant vacuolated cytoplasm in a background of small mature lymphocytes. “Tigroid” background due to spilled cytoplasmic glycogen.
What is NUT midline carcinoma?
A rare, aggressive subtype of SQC characterized by poor differentiation with focal squamous differentiation. Defined by NUT-BRD4 t(15;19) fusion and NUT IHC overexpression.
