Atrophic variant: The tumor cells of prostate cancer are usually cytoplasmically rich, but can sometimes be cytoplasmically sparse and resemble the morphology of benign prostate glands. The atrophic variant of prostate cancer occurs after treatment, but can also be atrophic from the beginning. Atrophic variant prostate cancer should be distinguished from prostatic hyperplasia by the presence of a true infiltrate with small glands located between large benign glands. There is a lack of interstitial reaction between the glands, and the cancer cells may appear heterogeneous, with large nuclei and distinct nucleoli. Sometimes generalized adenocarcinoma can be seen around the atrophic variant of the cancer, which helps us to identify it. In contrast, benign prostate atrophy has a lobular distribution. A central dilated atrophic gland surrounded by clusters of small glands is known as PosT-atrophichyperplasia (PAH). There is no true infiltration of benign atrophy, and scattered atrophic glands infiltrating between large benign glands are not seen. The glandular epithelial cells are not heterogeneous, and there are no large nuclei or distinct nucleoli. There is often fibrosis between some of the atrophic glands. Pseudohypertrophic variant: Pseudohypertrophic prostate cancer has larger glands that can form branches and are easily confused with benign prostatic hyperplasia. However, pseudohypertrophic prostate cancer has many large glands that are densely distributed and can form a back-to-back phenomenon. The borders of its glandular cavity are flat and the cytoplasm of the tumor cells is richer. The tumor cells are heterogeneous, with large nuclei and distinct nucleoli. Immunohistochemical staining shows no basal cells around the tumor cells to differentiate them from prostatic hyperplasia. Foam-like variant of prostate cancer: The foam-like variant of prostate cancer is characterized by abundant foamy cytoplasm of tumor cells, often without enlarged nuclei and obvious nucleoli, and small nucleoplasm ratio, which can be easily confused with benign prostate hyperplasia. However, the nuclei of foamy cells are small and densely stained, with round nuclei, crowded glands and interstitial infiltrates, and dark red anaplastic secretions are often seen. In most cases, foamy adenocarcinoma is often associated with common adenocarcinoma. Despite the benign morphology of foamy adenocarcinoma cells, the grade of the accompanying common adenocarcinoma is not low, and foamy adenocarcinoma is best classified as a moderate grade carcinoma. Although the cytoplasm of the foamy variant is yellow verrucous, the cytoplasm contains vacuoles rather than lipids. Mucinous and indolent variants: Mucinous adenocarcinoma of the prostate is a rare type that is diagnosed when at least 25% of the areas of prostate cancer contain extracellular mucinous lakes. Sieve-like structures are often present in the mucinous-like areas. Sometimes prostate cancer contains imprinted cells, but its intracellular vacuoles do not contain mucus. These vacuole-containing cells may infiltrate the interstitium singly, be located in the gland, or be lamellar in shape. There are only a few cases reported in the literature in which mucus is contained within the printed ring cells. In very rare cases in situ and invasive carcinomas originating from prostatic urothelial glandular metaplasia are mucinous adenocarcinomas, which have a morphology consistent with that of adenocarcinomas occurring in the bladder. The mucinous adenocarcinoma of the prostate is surrounded by a large mucinous lake with tall columnar epithelial cells, accompanied by cupped cells, with variable heterogeneity of the nuclei and with mucinous containing imprinted cells in the cytoplasm, but immunohistochemical staining of these cells is negative for PSA and PAP, which can be distinguished from mucinous adenocarcinoma of the prostate. Mucinous adenocarcinoma of the prostate has an infiltrative growth, and it has been reported in the literature that 7/12 patients in a group of mucinous adenocarcinoma die from the tumor (mean 5 years) and 5/12 patients survive with the tumor (mean 3 years). Mucinous adenocarcinomas of the prostate tend to metastasize to bone and are associated with elevated serum PSA. Eosinophilic variant: Prostate adenocarcinoma may occasionally be composed of large cytoplasmic cells containing eosinophils. The nuclei of tumor cells are round and ovoid with dark nuclear staining, and the tumor cells express strong positive PSA. Electron microscopy reveals a large number of mitochondria in the cytoplasm. The literature reports that carcinomas with eosinophilic variants have a higher Gleason grade, elevated PSA in the serum, and metastatic foci with similar morphology to the primary foci. Lymphoepithelioma-like variant: This type of carcinoma is characterized by syncytial cell-like tumor cells with dense and numerous lymphocytic infiltrates in the interstitium. Immunohistochemical staining shows that the tumor cells express PSA positively, which can be associated with adenoid cell carcinoma. The clinical significance of the lymphoepithelioid variant is to be determined. Sarcomatoid variant (sarcomatoid carcinoma): Sarcomatoid carcinoma of the prostate is very rare and consists of a malignant epithelial component with malignant spindle cells and mesenchymal components. It can start out as a carcinosarcoma or as an adenocarcinoma. It becomes sarcomatoid carcinoma after radiotherapy and hormonal therapy. Microscopically, sarcomatoid carcinoma is seen to have a variable degree of differentiation, with the sarcomatoid component consisting of nonspecific malignant spindle cells. Specific components such as osteosarcoma, chondrosarcoma, rhabdomyosarcoma, smooth muscle sarcoma, liposarcoma, angiosarcoma, or pleomorphic heterogeneous components may 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 is positive for PSA and broad-spectrum keratin, while the spindle cell component may be positive for various soft tissue tumor markers. It may express keratin positive or negative. In most patients, PSA in serum is within the normal range. At the time of diagnosis, patients often have metastases to lymph nodes and distant organs. The 5-year survival rate of patients is less than 40%.