2 Pa.C.S. § 703: Scope of review.

(a) General rule.--A party who proceeded before a Commonwealth agency under the terms of a particular statute shall not be precluded from questioning the validity of the statute in the appeal, but such party may not raise upon appeal any other question not raised before the agency (notwithstanding the fact that the agency may not be competent to resolve such question) unless allowed by the court upon due cause shown.

(b) Equitable relief.--The remedy at law provided by subsection (a) shall not in any manner impair the right to equitable relief heretofore existing, and such right to equitable relief is hereby continued notwithstanding the provisions of subsection (a).