Schwannomas are tumors of neoplastic Schwann cells generally found in peripheral nerves in the head, neck, and extremities. They do not demonstrate hormonal abnormalities, and initial symptoms are typically secondary to adjacent organ compression. These tumors are rarely found in the retroperitoneum. We present a rare finding of an adrenal schwannoma in a 75-year-old female who presented to the emergency department with right flank pain. Imaging incidentally demonstrated a 4.8 cm left adrenal mass. Ultimately, she underwent a left robotic adrenalectomy, and immunohistochemical testing confirmed the presence of an adrenal schwannoma. It is imperative to undergo adrenalectomy and immunohistochemical testing to confirm the diagnosis and rule out malignancy.