pseudohypertrophy

from The Century Dictionary.

• noun The enlargement of an organ without increase of its proper tissue, as when in muscular pseudohypertrophy there is increase of fat and connective tissue while the muscle-fibers are atrophied.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Enlargement at the site of an organ or part resulting from an increase in size or number of a separate tissue.