Histological appearances

Histological appearances

The prostate is a glandular structure consisting of ducts and acini; thus, the histological pattern is one of an adenocarci - noma. The prostatic glands are surrounded by a layer of myoepithelial cells. The first change associated with carcinoma is the loss of the basement membrane, with glands appearing to be in confluence. As the cell type becomes less di ff erentiated, mor e solid sheets of carcinoma cells are seen. A classification of the histological pattern based on the degree of glandular dedi ff erentiation and its relation to stroma has been devised - by Gleason. Prostate cancers exhibit heterogeneity within tissue, and so two histological areas of prostate are each scored between 3 and 5. Grades 1 and 2 are now not reported as their outcome is similar to grade 3. Grade 3 cancers almost never metastasise. The scores are added to give an overall Gleason score of between 6 and 10; this (and the volume of the cancer) appears to correlate well with the likelihood of spread and the prognosis. The International Society of Urological Pathology (ISUP) and WHO have recommended a simplified grading system composed of five prognostic grade groups. Each group has prognostic significance and a higher grade group has a poorer prognosis. Grade groups are as follows: /uni25CF 1 /uni00A0 = /uni00A0 Gleason score 3 /uni00A0 + /uni00A0 3 /uni00A0 = /uni00A0 6 /uni25CF 2 /uni00A0 = /uni00A0 Gleason score 3 /uni00A0 + /uni00A0 4 /uni00A0 = /uni00A0 7 /uni25CF 3 /uni00A0 = /uni00A0 Gleason score 4 /uni00A0 + /uni00A0 3 /uni00A0 = /uni00A0 7 /uni25CF 4 /uni00A0 = /uni00A0 Gleason score 8 (4 /uni00A0 + /uni00A0 4 /uni00A0 = /uni00A0 8, 3 /uni00A0 + /uni00A0 5 /uni00A0 = /uni00A0 8, 5 /uni00A0 + /uni00A0 3 /uni00A0 = /uni00A0 8) /uni25CF 5 /uni00A0 = /uni00A0 Gleason score ≥ 9 (4 /uni00A0 + /uni00A0 5 /uni00A0 = /uni00A0 9, 5 /uni00A0 + /uni00A0 4 /uni00A0 = /uni00A0 9, 5 /uni00A0 + /uni00A0 5 /uni00A0 = /uni00A0 10)

Figure 84.19 Osseous metastases of the pelvic bones in carcinoma of the prostate (courtesy of LN Pyrah, Leeds, UK).