Endocrine Disorders Flashcards
What is the risk of thyroid cancer after radiation exposure?
What is the most common form of cancer following radiation to the neck?
past history (10-25 years) of low-dose ionizing radiation « 2000 rad) to the neck carries a 40% risk of thyroid cancer; the most common cancer following radiation is papillary carcinoma
Which parts of the history are important to rule out thyroid cancer?
Radiation exposure, family history, thyroid nodule pattern, depressive symptoms.
And a patient with a 1 cm right thyroid nodule and history of radiation exposure, what is the next step?
Proceed directly to thyroidectomy
A patient has a family history of medullary cancer. How could you test for this type of cancer?
- autosomal dominant trait, and
- testing for the existence of a point mutation of the RET gene in a family can establish a diagnosis.
What voice and airway symptoms would suggest a malignancy?
history of hoarseness as well as the
- presence of a hard, fixed nodule
- dyspnea
-dysphagia - cervical lymph node enlargement; and
- vocal cord paralysis suggest malignancy
What is the risk of malignancy for a solitary nodule versus a dominant nodule in a multinodular gland?
Solitary nodule – 15%
Dominant nodule in a multinidular gland – 5%
What is the management of a thyroid cyst?
cyst necessitates complete aspiration and follow-up. If it is large (>4 cm) or recurs several times following aspiration, removal to eliminate the risk of malignancy (up to 15% in large cysts) is required.
Management of a colloid nodule?
Benign
Medical management of thyroid suppression
Papillary carcinoma
Surgery
Medullary carcinoma
Malignant highly invasive. Surgery
Psammoma bodies
Precursors for papillary carcinoma. Surgery recommended.
Amyloid deposits
substance and calcitonin staining suggest medullary cancer, and a total thyroidectomy is mandatory.
Undifferentiated cells
indicates an anaplastic cancer, and either chemotherapy and radiation or salvage operative therapy is appropriate.
Hurthle cells
Hurthle cells signifies either an adenoma or a low-grade cancer.
Therefore, lobectomy is indicated. If cancer is present, a total thyroidectomy is indicated.
Follicular cells
nondiagnostic result does not exclude cancer, so a thyroid lobectomy is usually performed for diagnostic purposes.
Lymphocytic infiltrate
lymphoma or chronic lymphocytic thyroiditis, which can be differentiated by flow cytometry. Lymphomas are radiosensitive, so radiation is approp
You should advise your patient of which serious complications of thyroid surgery?
Serious complications following thyroid surgery include injury to the recurrent laryngeal, or external branch of the superior laryngeal nerves as well as to the parathyroid, with resultant hypocalcemia and hyperphosphatemia.
Incidence of papillary cancer. What age is it typically diagnosed? What percentage of patients diagnosed will already have distant spread?
Most common thyroid cancer.
30–40 years old
5%
Management of papillary cancer with a nodule less than 1 cm in size.
– Patients with a previous history of radiation: total thyroidectomy
– Patients with no history of radiation: thyroid lobectomy and isthmusectomy
Incidence of follicular cancer? Where is this cancer more prevalent? What is the peak age of incidence?
Follicular cancers, which represent 15%-20% of thyroid cancers, are more prevalent in iodine-deficient areas. Peak incidence occurs about 40-50 years of age.
Treatment for follicular carcinoma
Formal lobectomy and isthmusectomy is appropriate for excision of a well-circumscribed lesion that is defined as a microinvasive follicular carcinoma. However, total thyroidectomy is necessary for microinvasive lesions greater than 4 cm.
How this follicular carcinoma usually spread?
Vascular route. Lymph node spread not as likely
What percentage of thyroid cancers does medullary cancer account for? What are the two forms?
Medullary cancer constitutes 5%-10% of all thyroid cancers. There are two forms: 80% are sporadic, and 20% are familial (MEN).
Describe the histology of medullary cancer cells
tumors feature hyperplasia of C cells (parafollicular) with amyloid.
The prognosis of papillary cancer depends on what variables?
One prognostic method uses a scale that includes age 40 years), pathologic grade, extent of disease, and size of tumor (mnemonic: AGES).
Prognostic factors in follicular cancers?
presence of vascular invasion worsens the prognosis. Survival is approximately 80% for favorable lesions and 60% for unfavorable lesions at 10 years. Postoperative adjuvant therapy centers on J131 ablation treatment.
What is the prognosis of medullary cancer?
Prognosis is related to the extent of disease, with an overall survival of 80% at 10 years, but less than 45% with lymph node involvement. Patients may be monitored by measuring serum calcitonin and carcinoembryonic antigen (CEA) levels.