悪性腫瘍

1. Origins, structure, and basic meaning

• Structure: 悪性腫瘍 (あくせいしゅよう) is a medical compound noun combining malignant status with the disease category tumor.
• Basic usage: 悪性腫瘍が見つかる makes the detected diagnosis the grammatical subject, while 悪性腫瘍と良性腫瘍 sets it as one category contrasted with a benign tumor.

2. Common pitfalls and similar expressions

• Malignant versus benign classification
  • The contrast between 悪性腫瘍 and 良性腫瘍 shows that 悪性 restricts the tumor’s classification. Dropping that element would erase the distinction established by the example.