The metastatic potential of prostate carcinomas composed entirely of single malignant glands

Histologic features of metastatic prostate cancer

Prostate carcinomas begin as well-differentiated lesions. Before metastases occur these carcinomas dedifferentiate into moderately or poorly differentiated lesions and increase in size to at least 1 cm3. Well-differentiated lesions rarely metastasize and metastases are rarely well differentiated. Positive staging lymphadenectomies usually contain moderately differentiated metastases. Patients with moderately differentiated metastases have a statistically significant better survival than patients with poorly differentiated metastases. Metastases typically disseminate as they dedifferentiate, with stage D1 metastases being moderately differentiated and stage D2 metastases being poorly differentiated. "Prostate-specific" immunohistochemical techniques and serum prostate-specific antigen levels may be helpful in determining whether a particular metastases is from the prostate. However, metastases of uncertain origin should rarely, if ever, be attributed to the prostate without confirmation that the patient has a prostate carcinoma with histologic features capable of metastasizing.

Stage D1 prostate carcinoma. The histologic appearance of nodal metastases and its relationship to survival

Eighty-two of 307 consecutive staging lymphadenectomies had nodal metastases (Stage D1 prostate carcinoma). Seventy-seven of the 82 cases had at least a 5-year follow-up and 50 had at least a 10-year follow-up. Three of these 77 cases had Grade 1 (well-differentiated) metastases, 59 (77%) had Grade 2-3 (moderately differentiated) metastases, and 15 (19%) had Grade 4 (poorly differentiated) metastases (M. D. Anderson Hospital [MDAH] grading system). The patients with moderately differentiated metastases had 5-year and 10-year survival rates of 79% and 34%, respectively, whereas the patients with poorly differentiated metastases had 5-year and 10-year survival rates of 13% and 0%, respectively (P less than 0.0001). This study demonstrates a statistically significant difference between the prognosis of Stage D1 patients with moderately differentiated metastases and Stage D1 patients with poorly differentiated metastases. Consequently, the evaluation of the histologic appearance of Stage D1 metastases may be of clinical importance.

The dedifferentiation of metastatic prostate carcinoma

Two hundred consecutive staging lymphadenectomies with metastatic prostate adenocarcinoma and 100 consecutive autopsies with widely disseminated metastatic prostate adenocarcinoma were identified. The metastases from 41% of the staging lymphadenectomies were entirely differentiated (gland forming) and an additional 43% were predominantly (50% or more) differentiated. In contrast, the metastases from 70% of the autopsies were entirely undifferentiated (non-gland forming) and an additional 18% were predominantly undifferentiated. Further, five patients with completely or predominantly differentiated metastases in staging lymphadenectomies were found to have widespread completely or predominantly undifferentiated metastases at autopsy 4-7 years later. These findings suggest that dedifferentiation occurs within metastases and that dedifferentiation within metastases may be important in understanding the widespread dissemination of metastatic prostate carcinoma.