Variants of acinar adenocarcinoma of the prostate mimicking benign conditions. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Histological variants of acinar adenocarcinoma of the prostate may be of significance due to difficulty in diagnosis or due to differences in prognosis compared to usual acinar adenocarcinoma. The 2016 World Health Organization classification of acinar adenocarcinoma includes four variants that are deceptively benign in histological appearance, such that a misdiagnosis of a benign condition may be made. These four variants are atrophic pattern adenocarcinoma, pseudohyperplastic adenocarcinoma, microcystic adenocarcinoma, and foamy gland adenocarcinoma. They differ from usual small acinar adenocarcinoma in architectural glandular structure and/or cytoplasmic and nuclear alterations. The variants are often admixed, in variable proportions, with usual small acinar adenocarcinoma that is often Gleason pattern 3 but may be high-grade pattern 4 in a minority of cases. Atrophic pattern adenocarcinoma can be identified in a sporadic setting or after radiation or hormonal therapy. This variant is characterized by cytoplasmic volume loss and can resemble benign glandular atrophy, an extremely common benign process in the prostate. The glands of pseudohyperplastic adenocarcinoma simulate usual epithelial hyperplasia, with gland complexity that is not typical of small acinar adenocarcinoma. These complex growth configurations include papillary infoldings, luminal undulations, and branching. Microcystic adenocarcinoma is characterized by cystic dilation of prostatic glands to a size that is much more commonly observed in cystic change in benign prostatic glands. Finally, the cells in foamy gland adenocarcinoma display cytoplasmic vacuolization and nuclear pyknosis, features that can found in benign glands and macrophages. Three of the four variants (atrophic, pseudohyperplastic, and microcystic) are assigned low-grade Gleason pattern 3. Of significance, foamy gland adenocarcinoma can be Gleason pattern 3 but can also be high-grade pattern 4 or 5. Diagnostic awareness of the existence of these deceptively benign-appearing variants of acinar adenocarcinoma is essential so that an accurate diagnosis of prostate cancer may be rendered. 10.1038/modpathol.2017.137

Pleomorphic giant cell carcinoma of prostate: Rare tumor with unique clinicopathological, immunohistochemical, and molecular features. El-Zaatari Ziad M,Thomas Jessica S,Divatia Mukul K,Shen Steven S,Ayala Alberto G,Monroig-Bosque Paloma,Shehabeldin Ahmed,Ro Jae Y Annals of diagnostic pathology Pleomorphic giant cell carcinoma (PGCC) of the prostate is a rare entity categorized as a variant of prostatic acinar adenocarcinoma in the 2016 World Health Organization (WHO) classification system. PGCC differs from conventional prostatic adenocarcinoma by having bizarre, markedly enlarged, and pleomorphic cells. It differs from high grade urothelial carcinoma by negativity for urothelial differentiation markers, and can be distinguished from sarcomatoid carcinoma by lack of spindle cells. Including two new cases described herein, there have been 51 cases of prostate PGCC reported in the English literature. Clinical features shared by cases of prostate PGCC include poor prognosis, occurrence in older patients, and frequent association with prior therapy. Pathologic features common to cases of prostate PGCC include admixture with a high-grade conventional prostate carcinoma component and absent or reduced expression of prostate differentiation markers. More recent studies have begun to elucidate the molecular characteristics of PGCC, detecting specific mutations and chromosomal translocations, and showing evidence of a high degree of molecular instability in these tumors. We report novel findings in two cases of PGCC including a PIK3CA p.His1047Arg mutation not previously described. One of our cases is the first to clearly demonstrate chronological loss of prostate markers during dedifferentiation from prior conventional prostate carcinoma to PGCC. Herein, we present our two new cases and comprehensively review the literature on all reported cases of PGCC with critical commentary on findings in cases of this rare tumor. 10.1016/j.anndiagpath.2021.151719

Diagnosis and Management of Primary Prostatic Signet Ring Cell Carcinoma: Single-Center Experience. Li Pu,Zhou Zihan,Bao Meiling,Li Jie,Meng Xiaoxin,Liu Bianjiang,Tang Min American journal of men's health The purpose of the study was to retrospectively summarize the diagnosis and management of 10 primary prostatic signet ring cell carcinoma (PPSRCC) cases in our center. Ten PPSRCC patients diagnosed at the First Affiliated Hospital of Nanjing Medical University from November 2014 to December 2020 were included. Clinical characteristics, image features, therapeutic procedures, histological diagnosis, and outcomes were retrospectively analyzed. All patients received prostate-specific antigen (PSA) examination preoperatively. Nine of them accepted multiparametric magnetic resonance imaging (mpMRI) due to elevated PSA value, and further biopsied. Among them, five patients were diagnosed as prostatic adenocarcinoma and the other four cases were found a mixture of signet ring cell carcinoma (SRCC) and adenocarcinoma. Furthermore, gastrointestinal endoscope and abdominal computed tomography (CT) did not find SRCC originating in gastrointestinal tract. Therefore, these cases were considered to be PPSRCC. Nine patients accepted laparoscopic or robot-assisted RP. Only one patient with normal PSA adopted transurethral resection of the prostate. Postoperative pathological results confirmed SRCC mixed with prostatic adenocarcinoma in nine cases, and only one patient with pure SRCC. After surgery, nine patients received adjuvant hormone therapy, one of which accepted radiotherapy simultaneously. The patient with pure SRCC did not accept any adjuvant therapy postoperatively. During a mean follow-up of 31.9 months, only four patients were alive without disease progression. In summary, PPSRCC is a rare malignant tumor with few specific symptoms, rapid disease progression, and poor prognosis and is frequently accompanied by high-grade prostate adenocarcinoma patterns. There is still no clear and effective strategy to improve the prognosis. 10.1177/15579883221087839