Tumours of the pluera

Question 1

Well-circumscribed plaques of dense collagen, often
containing calcium

Answer 1

Plueral Plaques

Question 2

What is the most common manifestation of asbestos exposure?

Answer 2

Plueral Plaques

Question 3

Localisation of plueral plaques

Answer 3

Develop most frequently on the anterior
& posterolateral aspects of the parietal pleura &
over the domes of the diaphragm

Question 4

Do plueral plaques contain asbestos bodies

Answer 4

NO

Question 5

Asbestos exposure induces

Answer 5

pleural effusions (usually serous but may also be bloody)

Question 6

Rare incidence in pleural plaques

Answer 6

Diffuse visceral pleural fibrosis may occur & in
advanced cases, bind the lung to the thoracic cavity wall

Question 7

Previously known as Fibroma

Answer 7

Solitary fibrous tumour

Question 8

Soft tissue tumour with a propensity to occur in the
pleura & less commonly in the lung (& other sites)

Answer 8

Solitary fibrous tumour

Question 9

Does Solitary fibrous tumour have relationship with asbestos exposure?

Answer 9

NO

Question 10

Macroscopic features of solitary fibrous tumour

Answer 10

Attached to the pleural surface by a pedicle
small (1-2 cm in diameter) or occasionally of enormous size
Cut surface: Whorled appearance

Question 11

Histologic findings of solitary fibrous tumour

Answer 11

Whorls of reticulin (a structural protein resembling
collagen, present in connective tissue as a network of fine fibers, especially around muscle & nerve fibers) & collagen fibers
Intermingled among them spindle cells, resembling
fibroblasts
Rarely, malignant (with following characteristics: pleomorphism, mitotic activity, necrosis & large size)

Question 12

Immunohistochemistry of

Answer 12

➢ Positive staining for CD34
➢ Negative staining for Cytokeratins
➢ DD: Malignant Mesothelioma (opposite phenotype)

Question 13

Arise from either the visceral or the parietal pleura

Answer 13

Malignant Mesothelioma

Question 14

Epidemiology of Malignant mesothelioma

Answer 14

90% of reported Mesotheliomas are Asbestos-related

Question 15

Is there an increased risk of Mesothelioma in asbestos workers who smoke (in contrast to the risk of asbestos-related Lung Carcinoma, already high, which is markedly magnified by smoking)

Answer 15

No

Question 16

60-80% of cases with malignant mesothelioma have deletion in chromosomes

Answer 16

1p, 3p, 6q, 9p or 22q

Question 17

31% of cases with malignant mesothelioma have mutations in

Answer 17

P16

Question 18

How does mesothelioma typically present in the pleural space?

Answer 18

Diffuse lesion, widely spread in the pleural space
Associated with extensive pleural effusion and direct invasion of thoracic structures
The lung becomes ensheathed by a thick layer of soft, gelatinous, grayish pink tumor tissue

Question 19

What are asbestos bodies, and what is their significance in mesothelioma?

Answer 19

Asbestos bodies are increased in the lungs of patients with mesothelioma & indicate asbestos exposure.

Question 20

What are the three histological types of mesothelioma?

Answer 20

Epithelioid (60%)
Sarcomatoid (20%)
Mixed (20%)

Question 21

What characterizes the epithelioid type of mesothelioma microscopically?

Answer 21

Cells: Cuboidal, columnar, or flattened
Structures: Tubular or papillary, resembling adenocarcinoma (Adeno-CA)

Question 22

How can epithelioid mesothelioma be differentiated from pulmonary adenocarcinoma (Adeno-CA) using immunohistochemistry?

Answer 22

Epithelioid Mesothelioma:
Lack of CEA staining
Strong staining for keratin proteins (accentuated perinuclear staining)
Positive staining for Calretinin, WT-1, CK 5/6, and D2-40
Adeno-CA: Expresses CEA

Question 23

What does the sarcomatoid type of mesothelioma resemble histologically?

Answer 23

Sarcomatoid type resembles spindle cell sarcoma, such as fibrosarcoma.

Question 24

What is the mixed type of mesothelioma?

Answer 24

Mixed type contains both epithelioid & sarcomatoid patterns.