Tumour regression

Tumour regression can occur as a consequence of treatment or sporadically.

Sporadic tumour regression

Well-known:

• Testicular germ cell tumours.
• Malignant melanoma.
• Neuroblastoma.

Microscopic

Features:

• +/-Fibrosis.
• +/-Mucin.
• +/-Inflammation.

Grading of tumour regression

There is a three tiered regression grading system by Ryan et al.

Note:

• There are specific criteria for malignant melanoma.