1. Simple or colloid Macrofollicular Adenoma
- Most common type
- Follicles of normal size
- Mostly stroma and minimal follicles
- Small follicles with minimal colloid
- Follicular cancer found in 5% of cases
Showing posts with label Thyroid. Show all posts
Showing posts with label Thyroid. Show all posts
Saturday, 29 May 2010
Thyroid adenoma
from http://www.fpnotebook.com/Endo/Hemeonc/ThyrdAdnm.htm.
1. Simple or colloid Macrofollicular Adenoma
1. Simple or colloid Macrofollicular Adenoma
Papillary carcinoma of the thyroid
Papillary carcinoma constitutes about two thirds of thyroid malignancies in adults and nearly all thyroid malignancies in children. Females are affected at least three times as often as males and the peak incidence is between 30y and 45y.
Histologically, the tumour forms a complex branching papillary structure with a fibrovascular stroma, often containing calcified 'psammoma bodies'.
Tumours vary over a wide range of epithelial dysplasia between apparently benign and obviously malignant.
Whatever the degree of dysplasia, the tumours grow slowly.
Papillary carcinomas are microscopically multicentric in about 80% of cases and about one third affect both lobes; this is important in planning treatment.
The tumour occasionally invades locally into trachea or oesophagus. Metastasis is to central cervical and later lateral cervical LNs and only rarely to distant sites such as lung or bone.
By presentation, LN are involved in about 40% of patients (90% in children).
LN enlargement is often the sole presenting feature and the histology of involved LNs is so close to normal thyroid tissue that at one time this condition was known as 'lateral aberrant thyroid'.
The prognosis of papillary carcinoma is the best of all thyroid carcinomas with only about 10% of patients dying of the tumour after 10y; it is remarkable that survival is hardly prejudiced by the presence of LN mets.
Symptoms and signs
Papillary ca presents as a slow-growing thyroid nodule.......... incomplete
Management
Total thyroidectomy because of the high risk of other foci within the gland.
Palpable cervical nodes are removed at the same operation. The operation is no more difficult than subtotal thyroidectomy but carries a higher risk of post-op hypoparathyroidism.
Total thyroidectomy has the added advantage that recurrent local disease, LN or distant mets can then effectively be treated with radioiodine (131I). This requires a very high TSH level which only occurs if no normal thyroid tissue remains.
A further advantage is that plasma thyroglobulin can then be used as a tumour marker to detect recurrent disease.
After treatment, hormone replacement is necessary to keep TSH close to zero to minimise the risk of stimulating any residual malignant cells.
Since papillary ca progress so slowly and only 15% develop contralateral lobe recurrence, some surgeons prefer to retain one thyroid lobe if the primary tumour is small and there are no palpable or isotope-detectable nodules. Their reasoning is that any further tumours can be removed later without reducing life expectancy.
Histologically, the tumour forms a complex branching papillary structure with a fibrovascular stroma, often containing calcified 'psammoma bodies'.
Tumours vary over a wide range of epithelial dysplasia between apparently benign and obviously malignant.
Whatever the degree of dysplasia, the tumours grow slowly.
Papillary carcinomas are microscopically multicentric in about 80% of cases and about one third affect both lobes; this is important in planning treatment.
The tumour occasionally invades locally into trachea or oesophagus. Metastasis is to central cervical and later lateral cervical LNs and only rarely to distant sites such as lung or bone.
By presentation, LN are involved in about 40% of patients (90% in children).
LN enlargement is often the sole presenting feature and the histology of involved LNs is so close to normal thyroid tissue that at one time this condition was known as 'lateral aberrant thyroid'.
The prognosis of papillary carcinoma is the best of all thyroid carcinomas with only about 10% of patients dying of the tumour after 10y; it is remarkable that survival is hardly prejudiced by the presence of LN mets.
Symptoms and signs
Papillary ca presents as a slow-growing thyroid nodule.......... incomplete
Management
Total thyroidectomy because of the high risk of other foci within the gland.
Palpable cervical nodes are removed at the same operation. The operation is no more difficult than subtotal thyroidectomy but carries a higher risk of post-op hypoparathyroidism.
Total thyroidectomy has the added advantage that recurrent local disease, LN or distant mets can then effectively be treated with radioiodine (131I). This requires a very high TSH level which only occurs if no normal thyroid tissue remains.
A further advantage is that plasma thyroglobulin can then be used as a tumour marker to detect recurrent disease.
After treatment, hormone replacement is necessary to keep TSH close to zero to minimise the risk of stimulating any residual malignant cells.
Since papillary ca progress so slowly and only 15% develop contralateral lobe recurrence, some surgeons prefer to retain one thyroid lobe if the primary tumour is small and there are no palpable or isotope-detectable nodules. Their reasoning is that any further tumours can be removed later without reducing life expectancy.
Follicular carcinoma of the thyroid
Info from Burkitt pg 720
Follicular carcinoma is another well-differentiated thyroid malignancy.
Histologically, the neoplastic cells form a well-developed follicular pattern which is impossible to distinguish from benign adenomatous hyperplasia on FNA cytology; even on histology of the surgical specimen, it may also be difficult to diagnose malignancy unless there is evident capsular or vascular invasion.
Unlike papillary carcinoma, multicentricity is common.
The peak incidence of follicular carcinoma is between 40y and 50y, older than for papillary ca, but it is still three times more common in women. Generally, follicular carcinoma grows slowly and metastasises at a late stage.
In contrast to papillary carcinoma, metastasis tends to occur via the bloodstream to the lungs, bone and other remote sites rather than to local lymph nodes.
Since follicular carcinoma is rarely multicentric, management depends on the extent of local invasion. A tumour with only microinvasion of the capsule has a very good prognosis and only requires removal of the thyroid lobe containing the tumour. If, however, there is gross capsular invasion or vascular invasion (or known remote mets), total thyroidectomy is performed.
The purpose of total thyroidectomy is not to treat the local tumour but to enhance radioiodine uptake by metastatic lesions should this be required later for diagnosis, or any consequent Rx with high-dose radioiodine (as with papillary carcinoma).
Prognosis can be predicted by the degree of capsular and vascular invasion by the primary lesion and on histology. If there is no invasion, 10y survival is close to 100% but this falls to 30% if there is extensive local invasion.
Follicular carcinoma is another well-differentiated thyroid malignancy.
Histologically, the neoplastic cells form a well-developed follicular pattern which is impossible to distinguish from benign adenomatous hyperplasia on FNA cytology; even on histology of the surgical specimen, it may also be difficult to diagnose malignancy unless there is evident capsular or vascular invasion.
Unlike papillary carcinoma, multicentricity is common.
The peak incidence of follicular carcinoma is between 40y and 50y, older than for papillary ca, but it is still three times more common in women. Generally, follicular carcinoma grows slowly and metastasises at a late stage.
In contrast to papillary carcinoma, metastasis tends to occur via the bloodstream to the lungs, bone and other remote sites rather than to local lymph nodes.
Since follicular carcinoma is rarely multicentric, management depends on the extent of local invasion. A tumour with only microinvasion of the capsule has a very good prognosis and only requires removal of the thyroid lobe containing the tumour. If, however, there is gross capsular invasion or vascular invasion (or known remote mets), total thyroidectomy is performed.
The purpose of total thyroidectomy is not to treat the local tumour but to enhance radioiodine uptake by metastatic lesions should this be required later for diagnosis, or any consequent Rx with high-dose radioiodine (as with papillary carcinoma).
Prognosis can be predicted by the degree of capsular and vascular invasion by the primary lesion and on histology. If there is no invasion, 10y survival is close to 100% but this falls to 30% if there is extensive local invasion.
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