Moreover, parafibromin-deficient tumors have shown a strong association with malignant behavior, with a younger age and larger tumor size, and present distinctive morphological (i.e., eosinophilic cytoplasm, very frequent presence of perinuclear cytoplasmic clearing, nuclear atypia and nuclear enlargement with distinctive coarse chromatin) and proliferative (extensive sheet-like growth rather than acinar architecture) features [31]. The gene discussed is CDC73; the disease is neoplasm.