Long term unilateral intermittent swelling - mid line on the bony jaw line. size of an almond, no real pain . ent and oral surgeon concerned but stumped. mri, ct and u/sound have not advanced a diagnosis. a cone beam demonstrated extremely vague shadow

Observation: Your workup seems quite complete except for a bone and or lymph node biopsy: are you prepared for these invasive procedures?

Neck: Hard to tell from the description. Maybe a small lymphangioma or embryonic cyst. If the MRI did not have contrast would not have been helpful

Biopsy: From the information supplied, biopsy with excision of mass may be indicated. Consider another oral surgery opinion.