Stem cells within the shoot apical meristem: identity, arrangement and communication.

Stem cells are specific cells that renew themselves and also provide daughter cells for organ formation. In plants, primary stem cell populations are nurtured within shoot and root apical meristems (SAM and RAM) for the production of aerial and underground parts, respectively. This review article summarizes recent progress on control of stem cells in the SAM from studies of the model plant Arabidopsis thaliana. To that end, a brief overview of the RAM is provided first to emphasize similarities and differences between the two apical meristems, which would help in better understanding of stem cells in the SAM. Subsequently, we will discuss in depth how stem cells are arranged in an organized manner in the SAM, how dynamically the stem cell identity is regulated, what factors participate in stem cell control, and how intercellular communication by mobile signals modulates stem cell behaviors within the SAM. Remaining questions and perspectives are also presented for future studies.

Electrical conductivity-based contrast imaging for characterizing prostatic tissues: in vivo animal feasibility study.

BACKGROUND: Electrical conductivity-based magnetic resonance (MR) imaging may provide unique information on tissue condition because its contrast originates from the concentration and mobility of ions in the cellular space. We imaged the conductivity of normal canine prostate in vivo and evaluated tissue contrast in terms of both the conductivity distribution and anatomical significance. METHODS: Five healthy laboratory beagles were used. After clipping the pelvis hair, we attached electrodes and placed each dog inside the bore of an MRI scanner. During MR scanning, we injected imaging currents into two mutually orthogonal directions between two pairs of electrodes. A multi spin echo pulse sequence was used to obtain the MR magnitude and magnetic flux density images. The projected current density algorithm was used to reconstruct the conductivity image. RESULTS: Conductivity images showed unique contrast depending on the prostatic tissues. From the conductivity distribution, conductivity was highest in the center area and lower in the order of the middle and outer areas of prostatic tissues. The middle and outer areas were, respectively, 11.2 and 25.5% lower than the center area. Considering anatomical significance, conductivity was highest in the central zone and lower in the order of the transitional and peripheral zones in all prostates. The transitional and peripheral zones were, respectively, 7.5 and 17.8% lower than the central zone. CONCLUSIONS: Current conductivity-based MR imaging can differentiate prostatic tissues without using any contrast media or additional MR scans. The electrical conductivity images with unique contrast to tissue condition can provide a prior information on tissues in situ to be used for human imaging.

A high-resolution gene expression map of the Arabidopsis shoot meristem stem cell niche.

The shoot apical meristem (SAM) acts as a reservoir for stem cells. The central zone (CZ) harbors stem cells. The stem cell progenitors differentiate in the adjacent peripheral zone and in the rib meristem located just beneath the CZ. The SAM is further divided into distinct clonal layers: the L1 epidermal, L2 sub-epidermal and L3 layers. Collectively, SAMs are complex structures that consist of cells of different clonal origins that are organized into functional domains. By employing fluorescence-activated cell sorting, we have generated gene expression profiles of ten cell populations that belong to different clonal layers as well as domains along the central and peripheral axis. Our work reveals that cells in distinct clonal layers exhibit greater diversity in gene expression and greater transcriptional complexity than clonally related cell types in the central and peripheral axis. Assessment of molecular functions and biological processes reveals that epidermal cells express genes involved in pathogen defense: the L2 layer cells express genes involved in DNA repair pathways and telomere maintenance, and the L3 layers express transcripts involved in ion balance and salt tolerance besides photosynthesis. Strikingly, the stem cell-enriched transcriptome comprises very few hormone-responsive transcripts. In addition to providing insights into the expression profiles of hundreds of transcripts, the data presented here will act as a resource for reverse genetic analysis and will be useful in deciphering molecular pathways involved in cell type specification and their functions.

Apparent Diffusion Coefficient Values of the Benign Central Zone of the Prostate: Comparison With Low- and High-Grade Prostate Cancer.

OBJECTIVE: The apparent diffusion coefficient (ADC) values for benign central zone (CZ) of the prostate were compared with ADC values of benign peripheral zone (PZ), benign transition zone (TZ), and prostate cancer, using histopathologic findings from radical prostatectomy as the reference standard. MATERIALS AND METHODS: The study included 27 patients with prostate cancer (mean [± SD] age, 60.0 ± 7.6 years) who had 3-T endorectal coil MRI of the prostate performed before undergoing prostatectomy with whole-mount histopathologic assessment. Mean ADC values were recorded from the ROI within the index tumor and within benign CZ, PZ, and TZ, with the use of histopathologic findings as the reference standard. ADC values of the groups were compared using paired t tests and ROC curve analysis. RESULTS: The ADC of benign CZ in the right (1138 ± 123 × 10(-6) mm(2)/s) and left (1166 ± 141 × 10(-6) mm(2)/s) lobes was not significantly different (p = 0.217). However, the ADC of benign CZ (1154 ± 129 × 10(-6) mm(2)/s) was significantly lower (p < 0.001) than the ADCs of benign PZ (1579 ± 197 × 10(-6) mm(2)/s) and benign TZ (1429 ± 180 × 10(-6) mm(2)/s). Although the ADC of index tumors (1042 ± 134 × 10(-6) mm(2)/s) was significantly lower (p = 0.002) than the ADC of benign CZ there was no significant difference (p = 0.225) between benign CZ and tumors with a Gleason score of 6 (1119 ± 87 × 10(-6) mm(2)/s). In 22.2% of patients (6/27), including five patients who had tumors with a Gleason score greater than 6, the ADC was lower in benign CZ than in the index tumor. The AUC of ADC for the differentiation of benign CZ from index tumors was 72.4% (sensitivity, 70.4%; specificity, 51.9%), and the AUC of ADC for differentiation from tumors with a Gleason score greater than 6 was 76.7% (sensitivity, 75.0%; specificity, 65.0%). CONCLUSION: The ADC of benign CZ is lower than the ADC of other zones of the prostate and overlaps with the ADC of prostate cancer tissue, including high-grade tumors. Awareness of this potential diagnostic pitfall is important to avoid misinterpreting the normal CZ as suspicious for tumor.

Apparent differences in prostate zones: susceptibility to prostate cancer, benign prostatic hyperplasia and prostatitis.

Men are inevitably plagued by prostate disease throughout their lives. However, the understanding of the pathogenesis of prostate diseases is still limited. In the 1960s, McNeal proposed the theory of prostate zones: the prostate was divided into three main zones: transition zone, central zone, and peripheral zone. Over the past 50 years, significant differences between different prostate zones have been gradually revealed. We summarized the most significant differences in different zones of the prostate. For the first time, we proposed the "apparent difference in prostate zones" concept. This new concept has been proposed to understand the different zones of the prostate better. It also provided new ideas for exploring the susceptibility of lesions in different prostate zones. Despite the reported differences between zones, the treatment of prostate-related diseases remains partition agnostic. Therefore, we also discussed the clinical significance of the "apparent difference in the prostate zone" and emphasized the necessity of prostate zones.

Striosomes Target Nigral Dopamine-Containing Neurons via Direct-D1 and Indirect-D2 Pathways Paralleling Classic Direct-Indirect Basal Ganglia Systems.

Balanced activity of canonical direct D1 and indirect D2 basal ganglia pathways is considered a core requirement for normal movement, and their imbalance is an etiologic factor in movement and neuropsychiatric disorders. We present evidence for a conceptually equivalent pair of direct-D1 and indirect-D2 pathways that arise from striatal projection neurons (SPNs) of the striosome compartment rather than from SPNs of the matrix, as do the canonical pathways. These S-D1 and S-D2 striosomal pathways target substantia nigra dopamine-containing neurons instead of basal ganglia motor output nuclei. They modulate movement oppositely to the modulation by the canonical pathways: S-D1 is inhibitory and S-D2 is excitatory. The S-D1 and S-D2 circuits likely influence motivation for learning and action, complementing and reorienting canonical pathway modulation. A major conceptual reformulation of the classic direct-indirect pathway model of basal ganglia function is needed, as well as reconsideration of the effects of D2-targeting therapeutic drugs.

Protoplasting and Fluorescence-Activated Cell Sorting of the Shoot Apical Meristem Cell Types.

The shoot apical meristems (SAMs) are located at the tip of the shoot apex. The SAM harbors stem cells that divide continually to provide cells for developing above-ground organs. Several important developmental events occur in SAMs, such as stem cell maintenance, organ differentiation, and flowering commitment which are under genetic control. The SAM is a collection of specialized cells organized in specific spatial domains. Deciphering the gene regulatory networks, guided by the developmental and environmental signals, in these discrete cell types is essential to decoding the SAM function. Here, I provide updates to the previously published protocols for the protoplasting and subsequent purification through fluorescence-activated cell sorting (FACS) of SAM cell types (Reddy, Fluorescence activated cell sorting of shoot apical meristem cell types. In: Riechmann JL, Wellmer F (eds) Flower development. Methods in molecular biology, vol 1110. Humana, New York, pp 315-321, 2014), which has provided genome-wide gene expression patterns at a single cell-type resolution.

Towards the Identification and Characterization of Putative Adult Human Lens Epithelial Stem Cells.

The anterior lens epithelium has the ability to differentiate into lens fibres throughout its life. The present study aims to identify and functionally characterize the adult stem cells in the human lens epithelium. Whole mounts of lens epithelium from donor eyes (normal/cataract) were immunostained for SOX2, gap junction protein alpha 1 (GJA1), PAX6, α, ß and γ-crystallins, followed by a confocal analysis. The functional property of adult stem cells was analysed by their sphere forming ability using cultured lens epithelial cells from different zones. Based on marker expression, the lens epithelium was divided into four zones: the central zone, characterized by a small population of PAX6+, GJA1-, ß-crystallin- and γ-crystallin- cells; the germinative zone, characterized by PAX6+, GJA1+, ß-crystallin- and γ-crystallin-; the transitional zone, characterized by PAX6+, GJA1+, ß-crystallin+ and γ-crystallin-; and the equatorial zone, characterized by PAX6+/-, GJA1+, ß-crystallin+, and γ-crystallin+ cells. The putative lens epithelial stem cells identified as SOX2+ and GJA1 membrane expression negative cells were located only in the central zone (1.89 ± 0.84%). Compared to the other zones, a significant percentage of spheres were identified in the central zone (1.68 ± 1.04%), consistent with the location of the putative adult lens epithelial stem cells. In the cataractous lens, an absence of SOX2 expression and a significant reduction in sphere forming ability (0.33 ± 0.11%) were observed in the central zone. The above findings confirmed the presence of putative stem cells in the central zone of the adult human lens epithelium and indicated their probable association with cataract development.

A new method to study learning and memory using spontaneous locomotor activity in an open-field arena.

BACKGROUND: Reduced locomotion with repeated exposure to a novel environment is often used as a measure of the basic adaptive learning process of habituation. While this is a well-established and reliable measure of habituation, it is not useful for the investigation of neurobiological changes before and after habituation because of the uncontrolled differential activity levels in a novel versus habituated environment. In this study we report a behavioral method that uses spontaneous locomotion to measure habituation, in which the total spontaneous locomotion in an initially novel environment does not change with repeated testing but, the ratio of central to peripheral activity does change and is indicative of habituation. The test sessions are brief (5 min) and the locomotion is measured in 2 separate zones. The peripheral zone comprises 8/9 of the test arena and the central zone 1/9 of the arena. RESULTS/COMPARISON WITH EXISTING METHODS: In contrast to methods that use between-session reductions in locomotion to assess habituation, this method employs brief test sessions in which overall activity between sessions does not change, but the distribution of locomotion in the periphery versus the central zone of the arena does change. The brevity of the test session also enables us to utilize post-trial drug treatment protocols to impact memory consolidation. CONCLUSIONS: The progressive change in the central/peripheral activity ratio with repeated testing can be determined independently of total activity and provides a habituation acquisition function that permits the measurement of neurobiological changes without the complication of effects related to changes in locomotor activity per se. The present report also presents evidence that this method can be used with post-trial drug treatment protocols to study the learning and memory effects of the post-trial treatments without the use of explicit rewards and punishments.

Cribriform Lesions of the Prostate Gland.

"Cribriform lesions of the prostate represent an important and often diagnostically challenging spectrum of prostate pathology. These lesions range from normal anatomical variation, benign proliferative lesions, premalignant, suspicious to frankly malignant and biologically aggressive entities. The concept of cribriform prostate adenocarcinoma (CrP4) and intraductal carcinoma of the prostate (IDC-P), in particular, has evolved significantly in recent years with a growing body of evidence suggesting that the presence of these morphologies is important for clinical decision-making in prostate cancer management. Therefore, accurate recognition and reporting of CrP4 and IDC-P architecture are especially important. This review discusses a contemporary diagnostic approach to cribriform lesions of the prostate with a focus on their key morphologic features, differential diagnosis, underlying molecular alterations, clinical significance, and reporting recommendations."

Small Cell-like Change in Central Zone Histology-A New Observation Mimicking Cribriform Intraductal Prostatic Adenocarcinoma.

A small cell-like change in prostate has been described in high-grade prostatic intraepithelial neoplasia (PIN), intraductal prostatic adenocarcinoma, and invasive prostate cancer. It occurs when these processes have a cribriform architecture. To date, small cell-like change has not been described in benign glands. Herein, I describe such a change in cribriform central zone histology from a radical prostatectomy with a spatially remote treatment naïve Grade Group 3 prostate cancer. The cancer did not have cribriform morphology or intraductal prostatic adenocarcinoma. The small cell-like change was positive for racemase in PIN-4 cocktail and no nuclei were highlighted by Ki-67. This is the first report of a small cell-like change in benign prostate tissue. Although rare, such finding in cribriform architecture of central zone histology can potentially be misinterpreted as a neoplastic process.

Risk factors of stillbirth among mothers delivered in public hospitals of Central Zone, Tigray, Ethiopia.

BACKGROUND: Stillbirth is a death before the complete expulsion or extraction from the mother. The burden is severe and high in developing countries. Risk factors for stillbirth are not yet studied in Ethiopia. OBJECTIVE: To identify risk factors of stillbirth among mothers delivered in public hospitals of Central Zone Tigray, Ethiopia. METHODS: A case-control study design was used. Data collection period was from January to April 2018. Study subjects 63 cases and 252 controls were selected using systematic random sampling technique from respective hospitals. The interviewer-administered questionnaire, observational, and chart analysis were used to collect the data. A binary logistic regression model was employed. Results were presented at significance level P-value <0.05. RESULTS: Maternal hypertension [AOR=12.83; 95% CI 3.38, 48.83], low birth weight [AOR=5.6; 95% CI 2.39, 13.38], pre-term [AOR=2.6;95%CI 1.12,6.16], alcohol intake [AOR=7.56; 95% CI 1.68, 34.04], polyhydramnios [AOR=13.43; 95% CI 3.63, 49.67], and meconium stained amniotic fluid [AOR=7.88; 95% CI 1.73, 8.18] were risk factors of stillbirth. CONCLUSION: The risk of stillbirth is increased with increasing maternal complication like maternal hypertension, alcohol consumption, polyhydramnios, and meconium-stained amniotic fluid. The occurrence of preterm and low birth weight of the fetus had an effect on the risk of stillbirth.

Determinants of hypothermia on neonates admitted to the intensive care unit of public hospitals of Central Zone, Tigray, Ethiopia 2017: unmatched case-control study.

OBJECTIVE: This study aims to identify determinants of hypothermia in neonates in neonatal intensive care unit of public hospitals of Central Zone Tigray, Ethiopia in 2017. RESULTS: A total of 88 cases and 176 controls were included in this study. Ninety-one percent cases and 86.4% controls were in the 1st week of neonate age. Multivariable logistic regression analysis showed that delayed initiation of breastfeeding [AOR = 7.23; 95% CI (2.75, 18.99)], low birth weight [AOR = 8.51; 95% CI (2.71, 26.73)], preterm [AOR = 3.689; 95% CI (1.359, 10.012)], low APGAR score at 5th min [AOR = 3.71; 95% CI (1.57, 8.79)], skin to skin contact [AOR = 6.23; 95% CI (2.523, 15.358)], night time delivery [AOR = 6.25; 95% CI (2.58, 15.12)] and bathed within 24 h [AOR = 10.06; 95% CI (3.86, 26.22)] were independent risk factors of neonatal hypothermia.

Risk factors of preterm birth among mothers who gave birth in public hospitals of central zone, Tigray, Ethiopia: unmatched case-control study 2017/2018.

OBJECTIVE: The aim of the study was to identify the risk factors for preterm birth in public hospitals of the central zone, Tigray, Ethiopia 2017/2018. RESULT: A total of 88 neonates who born preterm (cases) and 176 neonates who born term (controls) with their index mothers were included making a response rate of 100%. About 84/88 (95.5%) mothers in cases and 173/176 (98.3%) in control had antenatal care follow up. Among them, 33 (39.3%) cases and 102 (58%) controls were had antenatal care follow up four times and above. In multiple logistic regression at P-value < 0.05, mothers with ANC follow up less than four [AOR 95% CI 2.15 (1.19, 3.85)], mothers with pregnancy-induced hypertension [AOR 3.245; 95% CI (1.58, 6.67)], multiple pregnancy [AOR 2.47; 95% CI (1.14, 5.33)], fetal distress [AOR 4.0; 95% CI (1.9, 8.2)] and birth defect [AOR 3.19; 95% CI (1.22, 8.34)] were independent risk factors of preterm delivery.

Central-Variant Posterior Reversible Encephalopathy Syndrome with Albuminocytologic Dissociation.

Posterior reversible encephalopathy syndrome (PRES) is a disorder of reversible vasogenic brain edema which mainly involves the parieto-occipital lobes in various clinical settings. The main mechanism is known to be cerebral autoregulation failure and endothelial dysfunction leading to the disruption of the blood-brain barrier. We report the case of a 47-year-old woman with PRES which involved the brain stem and thalami, sparing the cerebral hemispheres. She was admitted to the emergency room because of acute-onset confusion. Her initial blood pressure was 270/220 mm Hg. Routine blood lab tests showed pleocytosis, hyperglycemia, and azotemia. Brain magnetic resonance imaging (MRI) showed a lesion of vasogenic edema involving nearly the whole area of pons, the left side of the midbrain, and the bilateral medial thalami. Cerebrospinal fluid (CSF) examination revealed an increased level of protein with normal white blood cell count. With conservative care, the patient markedly recovered 3 days after symptom onset, and a follow-up MRI confirmed complete resolution of the vasogenic edema. This case suggests that PRES can rarely involve the "central zone" only, sparing the cerebral hemispheres, which may be confused with other neurological diseases. Besides, the CSF albuminocytologic dissociation may suggest the disruption of the blood-brain barrier in patients with PRES.

Risk factors of birth asphyxia among newborns in public hospitals of Central Zone, Tigray, Ethiopia 2018.

OBJECTIVE: The aim of study was to identify risk factors of birth asphyxia among newborns in public hospitals of Central Zone Tigray, Ethiopia 2018. RESULTS: A total of 88 cases and 176 controls were included in the study. Thirty (34.1%) cases and 28 (15.9%) of controls were not able to read and write. Twenty-one (23.9%) cases and 9 (5.1%) controls were had meconium stained on pelvic examination. Multivariable logistic regression analysis showed that maternal illiteracy [AOR = 6; 95% CI (1.51, 23.80)], low birth weight [AOR = 6.9; 95% CI (3.01, 15.81)], preterm [AOR = 2.2; 95% CI (1.022, 4.76)], prim parous [AOR = 3.1; 95% CI (1.51, 6.38)], antepartum hemorrhage [AOR = 12; 95% CI (2.29, 63.11)] and meconium stained amniotic fluid [AOR = 7.88; 95% CI (2.92, 21.29)] were independent risk factors of birth asphyxia.

Central zone lesions on magnetic resonance imaging: Should we be concerned?

INTRODUCTION AND OBJECTIVE: The Prostate Imaging Reporting and Data System (PI-RADS) score was developed to evaluate lesions in the peripheral and transition zone on multiparametric magnetic resonance imaging (mpMRI) of the prostate. We aim to determine if the PI-RADS scoring system can be used to evaluate central zone lesions on mpMRI. MATERIALS AND METHODS: A retrospective review of 73 patients who underwent mpMRI/ultrasound (US) fusion-guided biopsy of 143 suspicious lesions between February 2014 and October 2015 was performed. All patients underwent a 3T mpMRI. Indications for mpMRI included an abnormal digital rectal examination, PSA velocity >0.75ng/dl/y, and patients on active surveillance. The mpMRI sequence involved T2-weighted imaging, diffusion-weighted imaging, and dynamic contrast enhancement. Using 3-dimensional model software (Invivo Corporation, Gainesville, FL, USA), a minimum of 3 magnetic resonance imaging (MRI)/US fusion-guided biopsy samples were taken from each prostate lesion seen on mpMRI irrespective of PI-RADS score, using local anesthesia in an outpatient clinic setting. RESULTS: A total of 73 patients underwent MRI/US fusion-guided biopsy of 85 peripheral zone lesions, 31 transitional zone lesions, and 27 central zone lesions. Only 2 (7%) of central zone lesions were positive for prostate cancer. Both patients had lesions which were graded as PI-RADS 3. Both the patients had multifocal lesions that encompassed≥50% of the central and transition zones on the sagittal view MRI images. Both patients previously had transrectal US-guided biopsy of the prostate which was negative for cancer. Both patients underwent a robotic-assisted laparoscopic prostatectomy, each revealing high-grade cancer. CONCLUSIONS: Lesions involving only the central gland/zone seen on MRI are less concerning for malignancy and should not be given equal weight as peripheral zone lesions. In this series, no lesions involving solely the central gland/zone, regardless of PI-RADS score, was positive for malignancy on MRI/US fusion-guided biopsy. Consideration of a modified PI-RADS scoring system should be given to help identify central zone lesions with malignant potential.

Evaluation of the relationship between hepatocellular carcinoma location and transarterial chemoembolization efficacy.

AIM: To evaluate the relationship between the location of hepatocellular carcinoma (HCC) and the efficacy of transarterial chemoembolization (TACE). METHODS: We evaluated 115 patients (127 nodules), excluding recurrent nodules, treated with TACE between January 2011 and June 2014. TACE efficacy was evaluated according to mRECIST. The HCC location coefficient was calculated as the distance from the central portal portion to the HCC center (mm)/liver diameter (mm) on multiplanar reconstruction images rendered (MPR) to visualize bifurcation of the right and left branches of the portal vein and HCC center. The HCC location coefficient was compared between complete response (CR) and non-CR groups in Child-Pugh grade A and B patients. RESULTS: The median location coefficient of HCC among all nodules, the right lobe, and the medial segment was significantly higher in the CR group than in the non-CR group in the Child-Pugh grade A patients (0.82 vs 0.62, P < 0.001; 0.71 vs 0.59, P < 0.01; 0.81 vs 0.49, P < 0.05, respectively). However, there was no significant difference in the median location coefficient of the HCC in the lateral segment between in the CR and in the non-CR groups (0.67 vs 0.65, P > 0.05). On the other hand, in the Child-Pugh grade B patients, the HCC median location coefficient in each lobe and segment was not significantly different between in the CR and in the non-CR groups. CONCLUSION: Improved TACE efficacy may be obtained for HCC in the peripheral zone of the right lobe and the medial segment in Child-Pugh grade A patients.

Assessing the validity of Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) scoring system in diagnosis of peripheral zone prostate cancer.

THE PURPOSE: Assessing the accuracy of multi parametric magnetic resonance (mp-MRI) after application of PI-RADS V2 for diagnosis of prostate cancer as comparison to pathological results of trans rectal ultra-sound (TRUS) guided biopsy. PATIENTS AND METHODS: 138 prostatic lesions in 23 patients were retrospectively assessed and analyzed with Trans rectal ultra-sound (TRUS) guided biopsy results. Those patients underwent multi parametric magnetic resonance (mp-MRI) with application of PI-RADS V2 reporting system. The sensitivity, specificity, validity, negative predictive value and positive predictive value were calculated for PI-RADS V2 reporting system compared to biopsy-proven pathological results. RESULTS: 92 out of 138 lesions were positive for Peripheral zone cancer prostate. PI-RADS V2 reporting system proved 88.04% sensitive & 93.4% specific for diagnosis of prostate cancer with negative predictive value & positive predictive value of 100%. CONCLUSION: Our results proved that mp-MRI of prostate using PI-RADS v2 scoring system had high sensitivity and specificity in diagnosis of prostate cancer and PI-RADS V2 scoring system using mp-MRI is recommended as a non-invasive diagnostic tool compared to TRUS guided biopsy.

Benign causes of diffusion restriction foci in the peripheral zone of the prostate: diagnosis and differential diagnosis.

Multiparametric-MRI is an important tool in the diagnosis of prostate cancer (PCa), particularly diffusion-weighted imaging for peripheral zone (PZ) cancer in the untreated prostate. However, there are many benign entities that demonstrate diffusion restriction in the PZ mimicking PCa resulting in diagnostic challenges. Fortunately, these benign entities usually have unique MR features that may help to distinguish them from PCa. The purpose of this pictorial review is to discuss benign entities with diffusion restriction in the PZ and to emphasize the key MR features of these entities that may help to differentiate them from PCa.