Salt and Pepper Sign

This sign is seen on MRI images in paragangliomas such as glomus tumors .

The sign is indicative of the hypervascularity of the mass. The 'pepper' represents multiple areas of signal void of vessels and the 'salt' represents the hyperintense foci due to slow-flow vessels or hemorrhages in these hypervascular tumors. The sign is seen in tumors that are more than 1 cm in diameter. The sign is not specific for paragangliomas and has been reported in other hypervascular lesions such as metastatic hypernephroma and metastatic thyroid carcinoma. Four common locations of paragangliomas in the head and neck are the carotid body, the jugular foramen, along the path of the vagus nerve, and the middle ear. Paragangliomas can be multiple and bilateral, especially in familial cases, and hence evaluation of the entire neck and of both sides is needed.

This term is used also for:

Sjogren syndrome
The parotid gland in Sjogren's syndrome has also been described as having a salt and pepper appearance, due to a combination of punctate regions of calcification (pepper) and fatty replacement (salt)

Vertebral haemangiomas
A less common usage for the term is for vertebral haemangiomas which have a courser black and white dotted appearance especially on axial T2 and T1 images (salt = fat, pepper = coarsened trabeculae).

MRI noise artefact
A related use of the term is to describe the noise sometimes seen in MRI images.

When you think about it, you can probably find folk who have used the term for all sorts of lesions... any lesion that has a fine granular imaging texture will do the trick.