AbstractThough outcomes for patients with recurrent/refractory malignant germ cell tumors (mGCTs) are poor, therapies targeting mTOR and EGFR inhibition have shown promise in vitro. We hypothesized that the combination of sirolimus and erlotinib will show activity in patients with recurrent/refractory mGCTs. Patients were enrolled in a prospective phase II clinical trial; central review of existing pathology specimens was performed. Of the five patients evaluated, two had their diagnoses revised to pancreatic acinar cell carcinoma and alpha‐fetoprotein (AFP)‐secreting gastric adenocarcinoma, respectively. Although mGCTs are common AFP‐secreting neoplasms, recurrence or refractoriness to standard regimens should prompt histologic reevaluation for other diagnoses.