This case requires us once again to consider the circumstances under which a federal district court has subject-matter jurisdiction over a claim for legal malpractice arising out of a patent dispute. Warrior Sports, Inc., a patent owner, filеd a malpractice action against the law firm of Dickinson Wright, P.L.L.C. (“Dickinson”), in the United States District Court for the *1369 Eastern District of Michigan. The district court regarded Warrior’s claims as raising only state law issues and therefore dismissed the action for lack of subject-matter jurisdiction. We conclude that at least one of Warrior’s malpractice claims requires the court to resolve a substantive issue of patent law. We therefore hold that 28 U.S.C. § 1338, which grants district courts exclusive jurisdiction over cases arising under a statute relаting to patents, invests the district court with subject-matter jurisdiction over the plaintiffs claims in this case. Accordingly, we vacate the dismissal order and remand this case to the district court for further proceedings.
I
Warrior owns a number of patents directed to lacrosse sticks and heads. One of the patents, U.S. Patent No. RE 38,216 (the '216 patent), is the focus of this litigation. During the prosecution of the application as well as the reissue proceedings and litigation asserting the '216 patent, Warrior was represented by attorneys John S. Artz and John A. Artz. For much of the relevant period, the two practiced together as Artz & Artz, P.C. Artz & Artz merged with Dickinson in June of 2007. For purposes of this appeal, Dickinson is treated as the successor-in-interest to Artz & Artz.
In January of 2004, Warrior asserted the '216 patent against a competitor, STX, L.L.C. STX argued that the '216 patent was unenforceable because of inequitable conduct. The unenforceability defense was based on conduct that occurred during the reissue proceedings, when John S. Artz allegedly mischaracterizеd the structure of a prior art lacrosse stick to the Patent and Trademark Office (“PTO”). The conduct that formed the basis for the inequitable conduct charge is one of the grounds alleged in Warrior’s malpractice action against Dickinson.
A second grоund of alleged malpractice is Warrior’s attorneys’ failure to pay the maintenance fee for the '216 patent when it became due in October of 2004. Artz & Artz did not pay the fee at that time, and the patent lapsed on October 29, 2004. STX later discoverеd that the patent had lapsed. Artz & Artz then initiated proceedings at the PTO seeking to have the patent reinstated, although Warrior alleges that Artz & Artz initiated the reinstatement proceedings without consulting Warrior.
The district court in the STX case bifurcated the litigatiоn and stayed the infringement action pending the outcome of a bench trial on inequitable conduct, which was held in July of 2008. Warrior and STX settled the entire case in October of 2008, before the court issued its ruling regarding enforceability. Accordingly, the infringement action was never tried.
Following the settlement of the STX litigation, Warrior sued Dickinson for malpractice in Michigan state court. Dickinson filed a motion for summary judgment challenging the state court’s subject-matter jurisdiction. The parties stipulated to the dismissal of the case and refiling in federal court. Warrior filed this action in the district court in June of 2009. In its complaint, Warrior cited a number of alleged errors by counsel, including the conduct that led to the allegation of inequitable conduct and the failure to pay the maintenanсe fee. Warrior argued that as a result of the alleged malpractice it was forced to settle the infringement action for less than the true value of its claim. Shortly before the complaint was filed in this case, the PTO accepted the late mаintenance fee and reinstated the '216 patent.
*1370 The district court directed the parties to brief the question whether it had jurisdiction over Warrior’s malpractice case. Each party filed a response stating that 28 U.S.C. § 1338 required the malpractice аction to be heard in federal court. The district court, however, disagreed with the parties and dismissed Warrior’s lawsuit for lack of subject-matter jurisdiction. The court characterized the patent-related issues as tangential; in the court’s view, the alleged acts of malpractice could all be analyzed without reference to patent law. Dickinson then appealed to this court.
II
We first address our jurisdiction to hear Dickinson’s appeal. This court has jurisdiction to decide an appeal from a final decision of a district court “if the jurisdiction of that court was based, in whole or in part, on section 1338.” 28 U.S.C. § 1295(a)(1). Section 1338 provides that the federal district courts have exclusive jurisdiction over “any civil action arising under any Act of Congress relating to patents.” 28 U.S.C. § 1338(a). It is true that the district court held that it did not have jurisdiction under section 1338. But it does not follow, as Warrior contends, that the district court’s decision divests this court of appellate jurisdiction under section 1295(a)(1).
In
C.R. Bard, Inc. v. Schwartz,
Ill
A
In
Christianson v. Colt Industries Operating Corp.,
In
Air Measurement Technologies,
we held that federal courts have exclusive jurisdiction over state-law legal malpractice actions when the adjudication of the malpractice claim requires the court to address the mеrits of the plaintiffs underlying patent infringement lawsuit.
B
Because Michigan law creates Warrior’s cause of action, we must decidе whether patent law is a “necessary element” of Warrior’s right to relief as set forth in its complaint.
Davis v. Brouse McDowell, L.P.A.,
The single count in the complaint can be divided into three claims: (1) negligence during the '216 reissue proceedings, allowing STX to invoke an inequitable conduct defense; (2) negligence in failing to pay the required maintenance fee on the '216 patent; and (3) negligence during the reinstatement proceedings for the '216 patent, including failing to pursue the reinstatement on a timely basis and failing to communicate with Warrior.
See Davis,
*1372 Under Michigan law, a malpractice plaintiff has the burden of proving four elements as part of a prima facie case:
(1) the existence of an attorney-client relationship;
(2) negligence by the attorney in the legal representation of the plaintiff;
(3) that the negligence was the proximate cause of plaintiffs injury; and
(4) the fact and extent of the injury alleged.
Coleman v. Gurwin,
VACATED and REMANDED
