Cardiac and Thymic Tumor Staging

What does grossing a heart usually include?

Procedure

Nature of specimen — Fresh vs fixative

Orientation

Integrity — Disrupted or intact

Dimensions

Anatomic components and size

How is pT1 for thymic tumors catergorized overall?

Limited to the thymus with OR without encapsulation

Directly invades into the mediastinal fat ONLY

Directly invades the mediastinal pleura but does NOT involve other mediastinal structures

(SIZE DETERMINES BETWEEN A OR B)

True or False: There is no grading for cardiac malignant tumors

True

What descriptors are used for heart specimens?

Macroscopic tumor

Focality

Site

Tumor size

Macroscopic appearance and extent and margin involvement

How are lymph nodes documented for heart specimens?

None

Number

Macroscopic involved nodes → Number

How common are primary cardiac tumors?

Extremely rare, occurring in approximately 0.001–0.3% of cases

What are the three major categories of malignant primary cardiac tumors?

Sarcoma

Carcinoma

Lymphoma

What are the most common sarcomas?

Angiosarcomas — MOST COMMON

Myosarcoma

• Leiomyosarcoma

• Rhabdomyosarcoma

What percentage of primary cardiac tumors are malignant?

Approximately 25%

What percentage of malignant primary cardiac tumors are sarcomas?

Approximately 75%

Are primary cardiac tumors more common in adults or children?

Children

What is the most common location of cardiac angiosarcoma?

Right atrium

What is the gross appearance of cardiac angiosarcoma?

Hemorrhagic

Fleshy

Infiltrative

Necrotic

Highly vascular

Which cardiac chamber should immediately raise suspicion for angiosarcoma when a hemorrhagic infiltrative mass is identified?

Right atrium

What is the single most important prognostic factor in cardiac sarcoma?

Tumor site

What additional prognostic features should be assessed?

Adjacent tissue involvement

Metastasis

Tumor necrosis

Mitotic count

What is the most common metastatic site for cardiac sarcomas?

Lung

What are the common metastatic sites of cardiac sarcomas in descending frequency?

1. Lung

2. Regional lymph nodes

3. CNS

4. GI tract

5. Kidney

6. Adrenal

7. Thyroid

8. Ovary

9. Bone

10. Pancreas

Is there a dedicated grading system for malignant cardiac tumors?

No. Soft tissue sarcoma grading systems are used.

What is the score 1 cardiac tumor stage?

Resembles normal adult tissue

What is the score 2 cardiac tumor stage?

Histologic type identifiable

What is the score 3 cardiac tumor stage?

Poorly differentiated/undifferentiated

Angiosarcoma commonly falls here

How is mitotic count scored with score 1?

0-9 Mitoses/10 HPF

How is mitotic count scored with score 2?

10-19 Mitoses/10 HPF

How is mitotic count scored with score 3?

≥20 Mitoses/10 HPF

How is tumor necrosis scored with score 1?

None

How is tumor necrosis scored with score 2?

<50%

How is tumor necrosis scored with score 3?

≥50%

How is histologic grade determined for cardiac tumors with a total score of 2-3?

Grade 1

How is histologic grade determined for cardiac tumors with a total score of 4-5?

Grade 2

How is histologic grade determined for cardiac tumors with a total score of 6-8?

Grade 3

A cardiac sarcoma has differentiation score 3, mitotic score 2, and necrosis score 2. What is the grade?

Total = 7

Grade 3

A cardiac sarcoma has differentiation score 1, mitotic score 1, and necrosis score 0. What is the grade?

Total = 2

Grade 1

Is there a formal staging system for primary malignant cardiac tumors?

No

What percentage of thymic tumors are thymomas?

66%

What percentage are thymic carcinomas?

20%

What percentage are thymic neuroendocrine tumors?

4%

What percentage are other tumor types for thymic tumors?

10%

Where is the thymus located?

Anterior mediastinum

What structures border the thymus?

Anterior → Sternum

Posterior → Pericardium, great vessels

Lateral → Pleural sacs

What are the normal age-related involution of the thymus?

Childhood: pink and lobulated

Adulthood: yellow-tan

Progressive fatty replacement

Fibrous septa remain

What does pT0 mean for thymic tumors?

No evidence of primary tumor.

What does pT1 mean for thymic tumors?

Tumor confined to thymus and/or extending into mediastinal fat or pleura

What is pT1a for thymic tumor T staging?

Tumor is ≤5 cm that (is):

• Limited to the thymus with OR without encapsulation

• Directly invades into the mediastinal fat ONLY

• Directly invades the mediastinal pleura but does NOT involve other mediastinal structures

What is pT1b for thymic tumor T staging?

Tumor is ≥5 cm that (is):

• Limited to the thymus with OR without encapsulation

• Directly invades into the mediastinal fat ONLY

• Directly invades the mediastinal pleura but does NOT involve other mediastinal structures

What defines pT2 for thymic tumors?

Direct invasion into:

• Pericardium (partial or full thickness)

• Lung

• Phrenic nerve

What defines pT3 for thymic tumors?

Direct invasion of:

• Brachiocephalic vein

• SVC

• Chest wall

• Extrapericardial pulmonary artery/vein

What defines pT4 for thymic tumors?

Direct invasion of:

• Aorta (ascending, arch, descending)

• Arch vessels

• Intrapericardial pulmonary artery

• Myocardium

• Trachea

• Esophagus

A 0.3 thymoma is completely encapsulated without invasion. What T stage?

pT1a

A 6 cm thymic tumor invades mediastinal pleura but no other structures. What T stage?

pT1b

A thymic carcinoma invades the pericardium. What T stage?

pT2

A thymic tumor invades lung parenchyma. What T stage?

pT3

A thymic tumor invades the superior vena cava. What T stage?

pT3

A thymic tumor invades myocardium. What T stage?

pT4

A thymic tumor invades the esophagus. What T stage?

pT4

A thymic tumor invades the aorta. What T stage?

pT4

What does pN0 mean for thymic tumors?

No regional nodal metastasis

What does pN1 mean for thymic tumors?

Metastasis to anterior/perithymic lymph nodes

What does pN2 mean for thymic tumors?

Metastasis to deep intrathoracic or cervical lymph nodes

Which nodal category generally indicates more advanced disease?

pN2

Tumor metastasis identified in perithymic lymph nodes. N stage?

pN1

Metastasis identified in supraclavicular lymph nodes. N stage?

pN2

Metastasis identified in internal mammary lymph nodes. N stage?

pN2

What node groups are in N1?

Low anterior cervical

• Pretracheal

• Paratracheal

• Perithyroid

• Precricoid

• Perithymic

• Para aortic

• Supradiaphragmatic

What node groups are in N2?

Lower jugular

Supraclavicular

Internal mammary nodes

Upper pre/para-tracheal

What does M0 mean for thymic tumors?

No pleural, pericardial, or distant metastases.

Do cardiac tumors use staging?

They do NOT use staging

What does pM1 mean for thymic tumors?

Pleural, pericardial, or distant mets

What does pM1a mean for thymic tumors?

Pleural or pericardial nodule

What does pM1b mean for thymic tumors?

Pulmonary intraparenchymal or distant organ me

Multiple pleural nodules identified. M stage?

M1a

Pericardial tumor implants are present. M stage?

M1a

Metastasis to liver identified. M stage?

M1b

Metastatic lung parenchymal nodules present. M stage?

M1b

Thymic tumor — What stage is T1a N0 M0?

Stage 1

Thymic tumor — What stage is T1b N0 M0?

Stage I

Thymic tumor — What stage is T2 N0 M0?

Stage II

Thymic tumor — What stage is T3 N0 M0?

Stage IIIA

Thymic tumor — What stage is T4 N0 M0?

Stage IIIB

Thymic tumor — What stage is Any T N1 M0?

Stage IVA

Thymic tumor — What stage is Any T N0 M1a?

Stage IVA

Thymic tumor — What stage is Any T N2 M0?

Stage IVB

Thymic tumor — What stage is Any T Any N M1b?

Stage IVB

Tumor invades pericardium but has no nodal or distant metastases. Stage?

T2 N0 M0

Stage II

Tumor invades lung parenchyma with no nodal metastasis. Stage?

T3 N0 M0

Stage IIIA

Tumor invades myocardium with no metastases. Stage?

T4 N0 M0

Stage IIIB

Tumor invades mediastinal pleura and metastasizes to perithymic lymph nodes. Stage?

T1b N1 M0

Stage IVA

Tumor is encapsulated but has pleural nodules. Stage?

T1a N0 M1a

Stage IVA

Tumor invades lung and has cervical node metastases. Stage?

T3 N2 M0

Stage IVB

Tumor invades only mediastinal fat but has liver metastases. Stage?

T1a N0 M1b

Stage IVB

What is Masaoka Stage I?

Completely encapsulated tumor with no transcapsular invasion

What is Masaoka Stage IIA?

Microscopic transcapsular invasion into mediastinal fat

What is Masaoka Stage IIB?

Macroscopic invasion into surrounding fat or mediastinal pleura

What is a modified staging for thymomas?

Masaoka staging

What is Masaoka Stage III?

Macroscopic invasion into neighboring organs:

• Lung

• Pericardium

• Great vessels

What is Masaoka Stage IVA?

Pleural or pericardial dissemination

What is Masaoka Stage IVB?

Lymphatic or hematogenous metastasis

Encapsulated thymoma with no invasion. Masaoka stage?

Stage I

Microscopic invasion through capsule into surrounding fat. Masaoka stage?

Stage IIA

Gross invasion into mediastinal pleura. Masaoka stage?

Stage IIB