Back to Previous Page


Image Number 32 - Lung, tuberculosis

Tuberculosis is caused by Mycobacterium tuberculosis. This disease is on the rise and the causative agent is gaining resistance to current medications. The characteristic lesion of TB is a caseating (cheesy) granuloma. Caseous material is not seen in this particular slide. In general, a granuloma is characterized by an aggregation of modified macrophages, called epithelioid cells because of their resemblance to squamous epithelial cells. Epithelioid cells may fuse to form a giant cell (Langhan's cell). A Langhan's cell is seen in the bottom left hand corner of this slide-the large pink cell with about 20 nuclei arranged in a horseshoe shape. Granulomas are found in many diseases-sarcoidosis for example. However, caseating granulomas are found in relatively few diseases e.g. TB and some of the fungal infections.

Click for image

To Next Image

To Table of Contents

To Alphabetical Index

To Start