the proceedings. There is nothing in the factual stipulation which identifies witnesses that have died, specific exculpatory evidence that has been destroyed, or specific matters that cannot be developed due to faded memories. We have generally required a factual showing of concrete prejudice before a defense of laches may be invoked. Iowa Supreme Ct. Bd. of Prof'l Ethics & Conduct v. Mulford, 625 N.W.2d 672, 680 (Iowa 2001). On the equitable estoppel issue, Wintroub’s argument has similar factual shortcomings. Even assuming that equitable estoppel applies in attorney grievance proceedings, nothing in the record of this ease supports the claim that Wintroub has relied upon any action of the Iowa authorities to his detriment. See The Florida Bar v. McCain, 361 So.2d 700, 706 (Fla.1978) (<HOLDING>). In this case, the Iowa complaints were filed,
holding an evidentiary hearing on the applicability of equitable estoppel holding equitable estoppel in disciplinary proceeding requires inducement to change position recognizing difference between tolling and equitable estoppel holding that equitable estoppel requires proof of fraud misrepresentation or affirmative deception recognizing cause of action for equitable estoppel under erisa