What are the pathological variations of prostate cancer

Atrophic variant: The tumor cells of prostate cancer generally have rich cytoplasm, but sometimes they may have scarce cytoplasm and resemble the morphology of benign prostate glands. Atrophic variant of prostate cancer usually occurs after treatment, but it can also be an atrophic variant from the beginning. Atrophic variant of prostate cancer should be differentiated from prostate hyperplasia. The key points of differentiation are: Atrophic variant of prostate cancer has true infiltration, and small glands can be seen between large benign glands. There is a lack of stromal reaction between the glands, and the cancer cells may show atypia, with large nuclei and obvious nucleoli.

Sometimes, general adenocarcinoma can be seen around atrophic variant carcinoma, which helps us identify it. Benign prostatic atrophy is distributed in lobular patterns. A centrally dilated atrophic gland is surrounded by clusters of small glands, which is called PosT-atrophichyperplasia (PAH). Benign atrophy has no true infiltration, and scattered atrophic glands cannot be seen infiltrating between large benign glands. Glandular epithelial cells have no atypia, no large nuclei and obvious nucleoli. Fibrosis is often present between some atrophic glands.

Pseudohypertrophic variant: The glands of pseudohypertrophic prostate cancer are larger and can form branches, which can be easily confused with benign prostatic hyperplasia. However, many large glands of pseudohypertrophic prostate cancer are densely distributed, forming a back-to-back phenomenon. The borders of the glandular cavity are straight, and the cytoplasm of the tumor cells is relatively rich. The tumor cells are atypical, with large nuclei and obvious nucleoli. Immunohistochemical staining shows that there are no basal cells around the tumor cells, which can be distinguished from prostatic hyperplasia.

Glandular foamy variation: The foamy variation of prostate cancer is characterized by abundant foamy cytoplasm in tumor cells, nuclei that are often not enlarged, and no obvious nucleoli, and a small nucleus-to-cytoplasm ratio, which can be easily confused with benign prostatic hyperplasia. However, the foamy cell nuclei are small and densely stained, the nuclei are round, the glands are crowded and have interstitial infiltration, and dark red acellular secretions can often be seen.

In most cases, foamy adenocarcinomas are associated with conventional adenocarcinomas. Although foamy adenocarcinoma cells are benign in appearance, the grade of the conventional adenocarcinomas they are associated with is not low, and foamy adenocarcinomas are best classified as intermediate-grade cancers. Although foamy variant cancer cells have xanthomatous cytoplasm, they contain vacuoles rather than lipids.

Colloid and signet ring variants: Mucinous adenocarcinoma of the prostate is a rare type that can only be diagnosed if at least 25% of the area in the prostate cancer contains extracellular mucin lakes. Crib-like structures are often present in the mucinous areas. Sometimes prostate cancer contains signet ring cells, but the vacuoles in the cells do not contain mucin. These vacuolated cells can be single infiltrates in the stroma, can be located in the glands, or in sheets. There are only a few cases reported in the literature where signet ring cells contain mucin.

In very rare cases, carcinoma in situ and invasive carcinoma originating from the metaplasia of the prostatic urethra are mucinous adenocarcinomas, and the morphology of mucinous adenocarcinoma is consistent with that of adenocarcinomas occurring in the bladder. Surrounding large areas of mucin lakes are tall columnar epithelial cells, accompanied by goblet cells, with varying degrees of nuclear atypia, and signet ring cells with mucin in the cytoplasm, but these cells are negative for PSA and PAP by immunohistochemical staining, which can be distinguished from prostate mucinous adenocarcinoma. Mucinous adenocarcinoma of the prostate grows invasively. Literature reports that in a group of mucinous adenocarcinomas, 7/12 patients died of tumors (average 5 years), and 5/12 patients survived with tumors (average 3 years). Mucinous adenocarcinoma of the prostate tends to metastasize to bones, accompanied by elevated serum PSA.

Eosinophilic variant: Prostate cancer may occasionally be composed of large cells with eosinophilic granules in the cytoplasm. The nuclei of the tumor cells are round or oval, with deep nuclear staining, and the tumor cells express strong positive PSA. Under the electron microscope, a large number of mitochondria are seen in the cytoplasm. Literature reports that eosinophilic variant cancer has a higher Gleason grade, elevated serum PSA, and the morphology of metastatic lesions is similar to that of primary lesions.

Lymphoepithelioma-like variant: This type of cancer cell is characterized by syncytial cell-like tumor cells and dense lymphocyte infiltration in the stroma. Immunohistochemical staining shows that the tumor cells express PSA positive, which can be associated with acinar cell carcinoma. The clinical significance of lymphoepithelioma-like variant is yet to be determined.

Sarcomatoid variant (sarcomatoid carcinoma): Sarcomatoid carcinoma of the prostate is very rare and is composed of malignant epithelial components and malignant spindle cells and mesenchymal components. It may start as a carcinosarcoma or an adenocarcinoma. After radiotherapy and hormone therapy, it becomes a sarcomatoid carcinoma. Microscopically, the degree of carcinoma differentiation in sarcomatoid carcinoma varies, and the sarcomatoid component is composed of non-specific malignant spindle cells. Specific components such as osteosarcoma, chondrosarcoma, rhabdomyosarcoma, leiomyosarcoma, liposarcoma, angiosarcoma or pleomorphic heterogeneous components can be seen. Sarcomatoid carcinoma must be differentiated from prostate cancer with benign bone and cartilage metaplasia.

Immunohistochemical staining shows that the carcinoma component of sarcomatoid carcinoma expresses PSA and broad-spectrum keratin positivity, while the spindle cell component can express various soft tissue tumor markers. It can express keratin positive or negative. In most patients, serum PSA is within the normal range. At the time of diagnosis, patients often have metastasis to lymph nodes and distant organs. The 5-year survival rate of patients is less than 40%.