A 38-year-old man presents with progressive testicular enlargement over 3 months. He reports a painless, firm mass on self-examination. Vital signs are stable. Physical examination confirms a 4 cm firm testicular mass without transillumination; no gynecomastia is present. Serum alpha-fetoprotein (AFP) is 2.3 ng/mL (normal), but serum beta-human chorionic gonadotropin (beta-hCG) is 35 mIU/mL (elevated). A testicular biopsy is performed. Under light microscopy, tumor cells are arranged in sheets separated by fibrous septa containing lymphocytes. Individual tumor cells have clear cytoplasm with distinct cell membranes, round nuclei with prominent nucleoli, and a high nuclear-to-cytoplasmic ratio. Which histologic feature best explains the clear appearance of the cytoplasm in these tumor cells?

1. A)Abundant rough endoplasmic reticulum and free ribosomes producing immunoglobulins
2. B)Glycogen and lipid accumulation within the cytoplasm, which dissolves during routine histologic processingGABARITO
3. C)Increased mitochondrial density and active oxidative metabolism
4. D)Hemosiderin and iron deposition from previous hemorrhage within the tumor
5. E)Mucin production with intracytoplasmic vacuolization compressing the nucleus peripherally