The benign type is seen in benign lesions such as benign tumors and following trauma. An aggressive type is seen in malignant tumors, but also in benign lesions with aggressive behavior, such as infections and eosinophilic granuloma.
When setting up a Hookah air system, you will frequently need an array of metal fittings. For use around water, you should use stainless steel or brass fittings only. This is especially important when diving in salt water. Fittings made of ferrous metal will rust or corrode when used in, or near a water environment.
1 Insert the bottom of the hookah stem into the top of the hookah base and fit the metal plate over the top of the stem. 2  Insert grommets into the top of stem and the stemâs hose port. 3  Attach the hose to the hose port, and check air flow by blocking the top of the stem with your hand and sucking in with the hose.