Lung Cancer - Pathology Flashcards
3 main types of primary lung epithelial cancers?
Non-Small Cell Lung Cancer (NSCLC)- 80%.
Small Cell - 15-20%.
Carcinoid. - 1-2%.
(and salivary gland-like… but don’t worry about that)
Broadly speaking, what kind of tumors are most commonly found in the lungs?
Metastases from other organs.
3 types of NSCLC?
Adenocarcinoma. (most common)
Squamous cell.
Large cell.
Typical demographic for patients with adenocarcinoma?
Women, non-smokers.
Adenocarcinoma of the lung histologic appearance?
Lots of gland, with or without mucus.
just like other adenocarcinomas we’ve seen
3 major grades of adenocarcinoma of the lung?
Non-invasive - Atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AAS).
Minimally invasive.
Invasive.
How are minimally invasive and invasive adenocarcinoma of the lung distinguished?
Depth of invasion: < 0.5 cm is minimally invasive.
Features of adenocarcinoma in situ (AIS)?
No invasion.
Lepidic growth - i.e. along alveolar surface.
Can be mucinous or non-mucinous.
(this was formerly called Bronchioloalveolar Carcinoma -BAC)
2 histologic patterns of a invasive adenocarcinoma?
Papillary (fibrovascular cores).
Acinar.
…but it can be mixed.
What’s a notable histologic feature of AIS, other than a lepidic growth pattern?
Cuboidal or columnar “hobnail” cells with atypical nuclei.
Mucinous AIS is rare, but what does it look like on histology?
Lots of mucinous, goblet-like cells. Lots of mucin.
3 histologic patterns of invasive adenocarcinoma?
Papillary. (fibrovascular cores)
Acinar. (gland-forming)
Solid (w. intracytoplasmic mucus)
Which NSCLC is most strongly associated with smoking?
Squamous cell carcinoma.
Why is bronchiectasis a common problem in squamous cell carcinoma of the lung?
2/3 of squamous cell carcinomas are central, and cause airway obstruction -> post-obstructive PNA, bronchiectasis.
2 histologic features of a lung cancer that suggest squamous cell differentiation?
Keratinization.
Intercellular bridges.
Pre-invasive lesion of squamous cell carcinoma?
Carcinoma in situ (CIS).
What’s a NSCLC without squamous or glandular differentiation?
Large cell carcinoma.
large cells with eosinophilic cytoplasmic, ugly nuclei
What are the 2 main lung cancers associated with smoking?
Squamous cell carcinoma.
Small cell carcinoma.
Small cell cancer is neuroendocrine… so are carcinoid tumors.
Okay.
Gross features of small cell carcinoma?
Usually central lesions.
Lots of lymphadenopathy.
What does small cell carcinoma look like histologically? (3 thigs)
Small cells (surprisingly) - about 2-3x a lymphocyte nucleus.
High N:C ratio.
Nuclei with salt & pepper chromatin.
Where in the lung do carcinoid tumors like to go?
They tend to be central (90%) and endobronchial.
What kind of symptoms do carcinoid tumors cause?
Obstructive symptoms (adult onset “asthma”), recurrent PNA, hemoptysis.
Histologic appearance of carcinoid tumor growth pattern?
Cell appearance?
Nests, cords, ribbons.
Round, ovoid, or spindle shaped cells… uniform cell size, abundant cytoplasm, fine granular chromatin.
What distinguishes an atypical from a typical carcinoid tumor?
of mitoses per high power field and necrosis:
Typical: < 2 mitoses per 10 hpf, no necrosis.
Atypical: 2-10 mitoses per 10 hpf and/or necrosis
(atypical is higher grade)
What’s a pulmonary hamartoma?
A benign tumor composed of… disorganized mature tissues, including lots of cartilage, fat, smooth muscle, calcification.
How do pulmonary hamartoma’s appear on radiology?
Well-circumscribed, solitary nodules, with calcifications (“popcorn calcifications”)
What do you call tumors arising from the pleura?
What about tumors of the pleura that come from elsewhere - where do they come from?
Mesothelial tumors are from pleura.
Other tumors of pleura come from mesenchyme (esp. solitary fibrous tumors), lymphoproliferative disorders, and mets.
Epidemiological association with malignant mesothelioma?
Asbestos exposure (and some other fibers) - with a long latency period (decades).
What does malignant mesothelioma look like grossly?
Thick tumor encasing the lungs and in the fissures.
Causes effusions.
Natural history of malignant mesothelioma?
Rapidly progressive and fatal.
2 major histologic types of mesothelioma?
Epithelioid
Sarcomatoid
Where do most solitary fibrous tumors arise?
In the visceral pleura,
Gross appearance of solitary fibrous tumors?
Solitary, well-circumscribed, firm, whitish, whorled.
Histologic appearance of solitary fibrous tumors?
Patternless…. with hypocellular and hypercellular areas.
Dense collagenous stroma with “spindle cells” that look like fibroblasts.
Should you assume that effusions to the pleura are malignant?
No, you should confirm with cytology.
From which organs do mets in the pleura most commonly originate?
Lung, breast, ovary
3 structures of the anterior and superior mediastinum?
Thymus.
Lymph nodes.
Sometimes thyroid or parathyroid tissue.
4 primary tumors of the anterior and superior mediastinum?
Recall that here, too, mets are more common than primary tumors.
The 4 T's: Thymoma. (Terrible) lymphoma. Teratoma (germ cell tumors), Thyroid or parathyroid conditions/tumors.
3 ways a thymoma can present?
Asymptomatic.
Immunologic effects.
Local mass effect.
Example of an immunologic effect of thymoma?
Mysasthenia gravis.
In thymoma, what’s the neoplastic cell?
Epithelial cells are the malignant cells.
Lymphocytes in the background are benign.
Structures of the middle mediastinum?
Lymph nodes, trachea, bronchi.
Heart and pericardium.
Great vessels.
Lesions of the middle mediastinum?
not just tumors
Mets. Lymphoma. Bronchogenic cysts. Pericardial cysts. Aortic aneurysm.
Structures of the posterior mediastinum?
Nerves, autonomic ganglia, lymph nodes, fat. Esophagus. Descending thoracic aorta. Azygous veins. Thoracic duct.
Lesions (not just tumors) of the posterior mediastinum?
Nerve sheath tumors (neurofibromas, Schwannoma). Esophageal cysts. Gastroenteric cysts. Thoracic duct cysts. Mets. Lymphomas.
