A 63-year-old female with an 80-pack-peryear smoking history has been complaining to her husband of feeling weak and being constipated. She also has abdominal pain. He brings her to the emergency room because she has started to act very odd including acting paranoid. While in the emergency room, she has a seizure. Laboratory testing reveals a total calcium of 13.0 mg/dL. On chest X-ray, she has a probable mass in the left upper lobe of the lung near the hilum.  what would a biopsy of the mass most likely reveal?