Here are three colonic polyps. One is a TA+LGD, another a TA+HGD and the final is a TVA+HGD
WHICH POLYP IS THE TVA?
Nope, this one has slit-like crypts typical of a tubular adenoma (TA). In fact, most small polyps are TA's. Presumably there is a progression from TA→TVA→Cancer apart from depressed lesions (IIc lesions) which go directly from being TA's to cancer.
It's a little difficult to see the crypt pattern without a close-up. However, you don't need to! Look at the growth morphology. This is a LST-NG and they are ALWAYS TA's!
Yes! Gyrate crypts best seen after indigocarmine dye spray (I think).
Most 'laterally spreading TVA's are of course LST-G's. However, this doesn't have the usual cobblestoned appearance of a 'laterally spreading tumour of the granular type'. It's rather 'chunky' in fact. That's because its harbouring HGD! A rare beast indeed as almost all laterally spreading TVA's only harbour LGD.