pachyderma n 1: thickening of the skin (usually unilateral on an extremity) caused by congenital enlargement of lymph vessel and lymph vessel obstruction [syn: {nevoid elephantiasis}, {pachyderma}]
pachyderma \pachyderma\ (p[a^]k"[i^]*d[~e]r"m[.a]), n. (Med.) An abnormal thickening of the skin (usually unilateral on an extremity) caused by congenital enlargement of lymph vessel and lymph vessel obstruction. Syn: pachydermatosis, pachydermia, nevoid elephantiasis. [WordNet 1.5]