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Endocrine Sequence - LAB 1
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.
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.
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.)
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.)
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.
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'