5. Neoplasms Flashcards
1
Q
Types of neoplasms
A
- Benign thyroid neoplasm
- Follicular adenoma & Hurthle cell adenoma - Thyroid carcinoma
- Follicular
- Papillary
- Anaplastic
- Medullary - Thyroid lymphoma
2
Q
Benign thyroid neoplasms
A
Follicular adenoma & Hurthle cell adenoma
3
Q
Morphology of follicular & hurthle cell ademona
A
- [Grossly]
- Rounded, encapsulated, well demarcated nodule
- Cut surface: regions of hemorrhage, cystic change & variable colour (red-brown if high colloid content; grey-white if high cellularity; orange brown if Hurthle cell change) - [Histologically]
- Thyroid follicles (mixed macro& microfollicles) within tumour substance
- Completely surrounded by an intact fibrous capsule which demarcates tumour from normal atrophic parenchyma (main distinguishing feature from multinodular goitre)
- May exhibit Hurthle cell change (Hurthle cell adenoma)
4
Q
Clinical Features of benign thyroid neoplasms
A
- Solitary painless nodule
- Laboratory tests
- Typically euthyroid
- Typically no increased radioiodine uptake - Differential diagnoses for follicular adenoma
- Dominant nodule in multinodular goitre
i. Multinodular goitre will not have a capsule & will have multiple other nodules in the background
- Follicular carcinoma
i. Follicular carcinoma will have capsular or vascular invasion
ii. Need to assess entire capsule via extensive histologic sampling of tumour-capsule-thyroid interface to make definite diagnosis (hence highlighting limitations of fine needle aspiration & frozen section assessment) - Papillary carcinoma (follicular variant)
i. Papillary carcinoma will have diagnostic nuclear features
5
Q
Cell of origin for follicular carcinoma
A
Follicular cell
6
Q
Frequency of follicular carcinoma
A
75-80%
7
Q
Age of diagnosis for follicular carcinoma
A
Mean 40
8
Q
Prognosis for follicular carcinoma
A
Good
9
Q
Genetic aberrations for follicular carcinoma
A
RAS, t(2;3)
10
Q
Morphology of follicular carcinoma
A
- [Grossly]
- Minimally invasive: well-defined, hard to find capsular invasion
- Widely invasive: obvious, extensive capsular or extrathyroidal extension
- Typically solitary - [Histologically]
- Similar to follicular adenoma EXCEPT that it has evidence of capsular/vascular invasion
- May have Hurthle cell change (Hurthle cell carcinoma)
11
Q
Clinical features of Follicular carcinoma
A
- Slow growing painless nodule (typically solitary)
- Little propensity for lymphatic spread, vascular spread common
- Prognosis: (depends on degree of invasion)
- Minimally invasive: 10-year survival > 90%
- Widely invasive: 10-year survival = 50-70%
12
Q
Cell of origin for papillary carcinoma
A
Follicular cell
13
Q
Frequency of papillary carcinoma
A
10-20%
14
Q
Prognosis for papillary carcinoma
A
Good
15
Q
Genetic aberrations for papillary carcinoma
A
RET (RET/PTC rearrangements), BRAF
16
Q
Morphology of papillary carcinoma
A
- [Grossly]
- May be solitary or mutilfocal
- Ranges from being encapsulated to infiltrative
- Whitish nodules, cystic change, calcifications & fibrosis
- Cut surface may reveal macroscopic papillary foci - [Histologically]
- Diagnostic nuclear features (present in all types of PTC):
i. Orphan Annie Eye nuclei (optically clear/empty looking due to finely dispersed chromatin)
ii. Nuclear grooves & pseudoinclusions (due to cytoplasmic invaginations)
- Classical PTC
i. Well formed papillae with fibrovascular cores
ii. Cuboidal uniform cells
iii. Psammoma bodies (concentrically calcified bodies within papillae cores)
iv. Fibrosis, calcifications
v. Lymphatic invasion - Follicular variant
i. Follicular architecture
ii. Note: need to distinguish from follicular adenoma & carcinoma (by using diagnostic papillary carcinoma nuclear features) - Encapsulated variant
i. Encapsulated - Tall cell variant
i. Tall columnar cells with intensely eosinophilic cytoplasm lining papillae - Papillary microcarcinoma
i. Otherwise classical PTC <1cm
17
Q
Clinical features of papillary carcinoma
A
- Diagnosed based on nuclear features
- Slow growing painless nodule (may be multifocal)
- Little propensity for vascular spread, lymphatic spread common
- Prognosis: (depends on age, extrathyroidal extension & distant metastases)
- Generally good prognosis
- Worse prognosis when associated with hoarseness, cough & dysphagia
- Histological type (encapsulated variant has excellent prognosis; tall cell variant tends to be more aggressive)
18
Q
Age of diagnosis of papillary carcinoma
A
40-50 years old
19
Q
Cell of origin of anaplastic carcinoma
A
Follicular cell
20
Q
Frequency of anaplastic carcinoma
A
<5%
21
Q
Age of diagnosis of anaplastic carcinoma
A
40-50 years old
22
Q
Prognosis of anaplastic carcinoma
A
Dismal
23
Q
Genetic aberrations for anaplastic carcinoma
A
p53
24
Q
Morphology of anaplastic carcinoma
A
- Giant tumour cells (osteoclast-like)
- Spindle cells (sarcomatoid features)
- Small anaplastic cells
25
Clinical features of anaplastic carcinoma
1. Rapidly enlarging bulky mass in the neck
2. Compressive symptoms (hoarseness, dyspnea, dysphagia)
3. Often spreads beyond thyroid gland with metastases to lung
4. Prognosis:
- Dismal, survival in months
26
Cell of origin of medullary carcinoma
Parafollicular cell
27
Frequency of medullary carcinoma
5%
28
Age of diagnosis of medullary carcinoma
Elderly
29
Prognosis of medullary carcinoma
Variable
30
Genetic aberrations for medullary carcinoma
RET (associated with MEN II)
31
Features of medullary carcinoma
1. Neuroendocrine tumour (derived from parafollicular cells of thyroid)
2. 80% sporadic, 20% familial (either part of MEN II syndromes or familial medullary thyroid carcinoma)
- Sporadic: localized to one lobe, no background of parafollicular cell hyperplasia, occurs in 5th to 6th decade of life
- Familial: multinodular & affects both lobes, background of parafollicular cell hyperplasia, occurs in 2nd decade of life
32
Morphology of medullary carcinoma
1. [Grossly]
- Firm, pale-grey to tan
- Infiltrative edges
- Necrosis & hemorrhage
- Extrathyroidal extension
2. [Histologically]
- Cells with variable appearance
- Variable architecture (nests, trabeculae, follicles)
- Background of amyloid (deposits of altered calcitonin, shown with Congo Red stain)
- Parafollicular cell hyperplasia in normal surrounding parenchyma (seen mainly in familial tumours)
33
Clinical features of medullary carcinoma
1. Compressive symptoms (dysphagia, hoarseness)
2. Paraneoplastic syndrome (VIP causing diarrhea, ACTH causing Cushing syndrome)
3. Raised serum calcitonin (but with no significant hypocalcemia)
4. Look out for other related tumours to determine if it is part of a MEN II syndrome (adrenals, parathyroid)
5. Prognosis: (depends on degree of invasion)
- Sporadic worse than familial
34
Definition of thyroid lymphoma
Extranodal marginal zone B-cell lymphoma, typically occurring in the setting of Hashimoto thyroiditis; may transform into diffuse large B-cell lymphoma
