pachyderma(n = noun.state) nevoid elephantiasis - thickening of the skin (usually unilateral on an extremity) caused by congenital enlargement of lymph vessel and lymph vessel obstruction;
is a kind of congenital disease, genetic abnormality, genetic defect, genetic disease, genetic disorder, hereditary condition, hereditary disease, inherited disease, inherited disorder, elephantiasis

   An abnormal thickening of the skin (usually unilateral on an extremity) caused by congenital enlargement of lymph vessel and lymph vessel obstruction. [WordNet 1.5]