Gleason Score 9-10

**Semantic type:** Classification

**Definition:** Prostate carcinoma lacking gland formation (or with necrosis) and with or without poorly formed/fused/cribriform glands. For cases with greater than 95% poorly formed/fused/cribriform glands on a core or at radical prostatectomy, the component of less than 5% well-formed glands is not factored into the grade; should therefore be graded as grade group 4. (ISUP, 2014)