Do you ever treat the contralateral neck for high grade mucoepidermoid salivary gland carcinomas?

I wont say never, but in general even in the scenario you describe I would say no. This is relatively controversial, and we once did an informal poll among a few HN XRT experts, and in this non-scientific poll a consensus was not reached on the subject.

No. But I have had patients with IA or medial supraclavicular nodes for whom I brought the field over the anterior midline.