Klairmont Matthew M, Zafar Nadeem
Matthew M Klairmont, Nadeem Zafar, Department of Pathology, University of Tennessee Health Science Center, Memphis, TN 38163, United States.
World J Clin Oncol. 2017 Jun 10;8(3):289-292. doi: 10.5306/wjco.v8.i3.289.
The oncocytic variant of prostatic adenocarcinoma is exceptionally rare with only 4 cases reported in the English literature. Little is known about the clinical behavior of this variant of prostatic adenocarcinoma, because of the exceptionally low number of reported cases. The 2016 World Health Organization Classification of Tumors of Prostate does not recognize the oncocytic variant, again likely related to the exceptional paucity of reported cases. Here, we report the fifth case of the oncocytic variant of acinar type prostatic adenocarcinoma in an asymptomatic 64-year-old Caucasian American male with elevated serum prostate specific antigen (7.33 ng/mL; normal range 0-4.00 ng/mL) during routine blood screening for diabetes mellitus. At subsequent transrectal prostate biopsy, the right side of prostate was infiltrated by adenocarcinoma with tumor cells forming variably differentiated glands, including some poorly differentiated. Tumor cell nuclear:cytoplasmic ratio was low, with small to intermediate sized vesicular nuclei and only rare discernable small nucleoli. Cellular cytoplasm was characteristically granular pink with sharply defined cell membranes. Positive AMACR (P504S) epithelial immunohistochemical staining and absence of staining for prostatic basal cells confirmed the tumor to be primary prostatic adenocarcinoma. AMACR immunohistochemical staining was also helpful with accurate grading of the tumor due to the difficulty of differentiating tumor cells from residual prostate myocytes at routine hematoxylin and eosin (HE) staining. This new case adds to the exceptionally small number of previously reported cases of the oncocytic variant of primary prostatic adenocarcinoma. It also highlights the difficulty associated with Gleason scoring of the oncocytic variant by routine HE evaluation and the usefulness of AMACR (P504S) immunostaining for accurate grading of prostatic adenocarcinoma in the oncocytic variant.
前列腺腺癌的嗜酸细胞变体极为罕见，英文文献中仅报道过4例。由于报道病例数量极少，人们对这种前列腺腺癌变体的临床行为知之甚少。2016年世界卫生组织前列腺肿瘤分类未认可嗜酸细胞变体，这可能同样与报道病例的极度稀缺有关。在此，我们报告了第5例腺泡型前列腺腺癌嗜酸细胞变体病例，患者为一名64岁无症状的美国白人男性，在糖尿病常规血液筛查中血清前列腺特异性抗原升高（7.33 ng/mL；正常范围0 - 4.00 ng/mL）。在随后的经直肠前列腺活检中，前列腺右侧被腺癌浸润，肿瘤细胞形成分化程度各异的腺体，包括一些低分化腺体。肿瘤细胞核与细胞质的比例较低，核呈小至中等大小的泡状，仅偶尔可见小核仁。细胞胞质呈特征性的颗粒状粉红色，细胞膜界限清晰。AMACR（P504S）上皮免疫组化染色阳性且前列腺基底细胞染色阴性，证实该肿瘤为原发性前列腺腺癌。由于在常规苏木精和伊红（HE）染色下难以区分肿瘤细胞与残留的前列腺肌细胞，AMACR免疫组化染色也有助于对肿瘤进行准确分级。这一新病例增加了原发性前列腺腺癌嗜酸细胞变体此前极少的报道病例数。它还凸显了通过常规HE评估对嗜酸细胞变体进行Gleason评分的困难，以及AMACR（P504S）免疫染色对嗜酸细胞变体前列腺腺癌准确分级的有用性。
