It means unbalanced in a big way. Unbalanced means not balanced, or skewed. Lopsided perhaps. And grossly means largely, greatly, or hugely... an adjective used to indicate the severity of whatever it modifies.
pancreas grossly normal
Grossly tender means it obviously hurts when touched.
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Grossly benign means that to the naked eye, it does not appear dangerous.
Grossly unremarkable means there is nothing interesting to talk about, its normal.
I think you read the result incorrectly. "Grossly remarkable" doesn't make sense. "Grossly unremarkable" means there was no obvious abnormality.
Grossly unchanged means that the subject in question did not change on a scale that could be noticed with the naked eye.
Good
in an obvious and unacceptable manner. Can be in a disgusting and coarse manner
Definition of grossly homogenous thyroid gland
He ate grossly.
Grossly is an adverb.