Unchanged hypoechoic nodule in the right lobe measuring 8 x 6 x 7 mm. this shows mainly peripheral vascularization. no evidence of internal microcalcification. follow-up at 12 months recommended. what this could be? it is too long for a year visit?

When scheduled surveillance studies like this show no increase in size or worrisome change in character it suggests it is stable/benign. The intervals suggested for repeat studies often lengthen when no changes are seen. The common practice would be decided by the doc who knows your case. No information was posted detailing what was being studied or why.