A 70-year-old male has a pathologic fracture of femur. The lesion appears a lytic on X-rays film with a circumscribed punched out appearance. The curetting from fracture site is most likely to show which of the following
Diminished and thinned trabecular bone fragments secondary to osteopenia Sheets of atypical plasma cells Metastatic prostatic adenocarcinoma Malignant cells forming osteoid bone