INSTRUCTORS ONLY

Endocrine Sequence - LAB 1

Slide 164 [WebScope] [ImageScope]

Thyroid: Multinodular goiter

The characteristic changes seen in multinodular goiter include multiple nodules of colloid-filled follicles of varying size with foci of hyperplastic epithelium, fibrosis, hemorrhage and hemosiderin deposition, calcification, and cyst formation. These features are best appreciated by low-power examination of the section.

1. How is multinodular goiter related to simple goiter?

2. What is the clinical significance of multinodular goiter?

Slide 165 [WebScope] [ImageScope]

Thyroid: Hashimoto's thyroiditis

This slide shows an advanced stage of Hashimoto's thyroiditis in which the normal thyroid gland architecture is largely replaced by fibrous tissue and infiltrates of lymphocytes and plasma cells accompanied by germinal centers. Careful examination reveals small, colloid-filled follicles embedded within the lymphoid infiltrate.

1. What is the typical clinical presentation of Hashimoto's thyroiditis?

2. What is its pathogenesis and what laboratory tests supports a diagnosis of Hashimoto's thyroiditis?

3. The incidence of what malignant neoplasm is increased in patients with Hashimoto's thyroiditis?

Slide 166 [WebScope] [ImageScope]

Thyroid: Papillary carcinoma

This section shows a typical papillary carcinoma. Note the following characteristic histologic features: the papillary growth pattern, the "ground glass" or optically clear appearance of the nuclei, the presence of nuclear grooves, and the presence of calcospherites or psammoma bodies (if present on your slide). Papillary carcinomas are strongly positive for thyroglobulin by immunohistochemistry. (Normal thyroid parenchyma is not present on this slide, so take a moment to compare these nuclei with those from Slide 164.)

1. What is the classification scheme (excluding variants) of epithelial thyroid tumors? What are their relative frequencies?

2. What is a well-known risk factor for papillary carcinoma of the thyroid?

3. What is the natural history course of papillary carcinoma and what are some of the prognostic factors that predict outcome?

Slide 163 [WebScope] [ImageScope]

Thyroid: Diffuse hyperplasia (Graves' disease)

This slide shows the classic diffuse hyperplasia of Graves' disease. There are simple follicles with abundant colloid and more complex follicles with less colloid and papillary fronds. Note that the hyperplastic process diffusely involves the gland without formation of discrete nodules. The follicular cells are taller than normal follicular cells. There is abundant scalloping of colloid. The nuclear features of papillary carcinoma are not present. (Take a moment to compare to Slide 166.)

1. How can patients with Graves' disease present clinically?

2. What auto-antibodies are associated with Graves' disease?

3. What are some of the other disorders associated with hyperthyroidism?

Slide 157 [WebScope] [ImageScope]

Pituitary adenoma

This slide contains a cellular neoplasm composed of nests of small cells with uniform nuclei and abundant cytoplasm. This is a pituitary adenoma. Look for evidence of normal pituitary at the periphery of the slide (hint: look for cells with brightly staining eosinophilic cytoplasm).

Pituitary adenomas used to be classified according to the histologic appearance of the cytoplasm (e.g. eosinophilic vs. basophilic). Extensive research has shown that there is no strong correlation between histologic appearance and hormone production. Pituitary adenomas are now classified based on hormone production. Currently, immunohistochemistry using monoclonal antibodies directed against individual pituitary hormones is preferred method to assay hormone production. Other methods employ electron microscopic examination of secretory granules and molecular studies of gene expression.

1. How can patients with pituitary adenomas present clinically?

2. What are the common hormones produced by pituitary adenomas?

The answers to the path lab questions will be posted approximately 48-72 hours after the lab sessions. These are abbreviated answers, not a full discussion of the topics. You can find them in the M2 CTools site resources. In the folder for each sequence the will be a folder called 'Path Lab Resources'