Variance of Tumor Grade at Radical Prostatectomy With Assessment of Each Tumor Nodule Versus Global Grading

Context.— Multifocal prostate cancer at radical prostatectomy (RP) may be graded with assessment of each individual tumor nodule (TN) or global grading of all TNs in aggregate. Objective.— To assess case-level grade variability between these 2 grading approaches. Design.— We reviewed 776 RPs with multifocal prostate cancer with 2 or more separate TNs of different Grade Groups (GGs). Two separate grades were assigned to each RP: one based on the TN with the highest grade and a global grade based on the Gleason pattern volumes for all TNs. We then compared the results of these 2 methods. Results.— The case-level grade changed by 1 or more GGs between the 2 grading methods in 35% (132 of 374) of GG3 through GG5 cases. Twelve percent (37 of 309) of GG2 cases with Gleason pattern 4 more than 5% based on individual TN grading decreased their Gleason pattern 4 to less than 5% based on the global approach. Minor tertiary pattern 5 (Gleason pattern 5 <5%) was observed in 6.8% (11 of 161) of GG4 (Gleason score 3 + 5 = 8 and 5 + 3 = 8) and GG5 cases with global grading. The risk of grade discrepancy between the 2 methods was associated with the highest-grade TN volume (inverse relationship), patient age, and number of TNs (P < .001, P = .003, and P < .001, respectively). Conclusions.— The global grading approach resulted in a lower grade in 35% of GG3 through GG5 cases compared with grading based on the highest-grade TN. Two significant risk factors for this discrepancy with a global grading approach occur when the highest-grade TN has a relatively small tumor volume and with the higher number of TNs per RP. The observed grade variability between the 2 grading schemes most likely limits the interchangeability of post-RP multi-institutional databases if those institutions use different grading approaches.

Prostatic Ductal Adenocarcinoma Controlled for Tumor Grade, Stage, and Margin Status Does Not Independently Influence the Likelihood of Biochemical Recurrence in Localized Prostate Cancer After Radical Prostatectomy

Context.— Prostatic ductal adenocarcinoma (PDA) has historically been considered to be an aggressive subtype of prostate cancer. Objective.— To investigate if PDA is independently associated with worse biochemical recurrence (BCR)–free survival after radical prostatectomy. Design.— A review of 1584 radical prostatectomies was performed to grade, stage, and assess margin status in each tumor nodule. Radical prostatectomies with localized PDA (ie, those lacking metastasis) in the tumor nodule with the highest grade and stage and worst margin status were matched with prostatic acinar adenocarcinoma according to grade, stage, and margin status. The effect of PDA on BCR was assessed by multivariable Cox regression and Kaplan-Meier analyses. Results.— Prostatic ductal adenocarcinoma was present in 171 cases. We excluded 24 cases because of lymph node metastasis (n = 13), PDA not in the highest-grade tumor nodule (n = 9), and positive surgical margin in a lower-grade tumor nodule (n = 2). The remaining 147 cases included 26 Grade Group (GG) 2, 44 GG3, 6 GG4, and 71 GG5 cancers. Seventy-six cases had extraprostatic extension, 33 had seminal vesicle invasion, and 65 had positive margins. Follow-up was available for 113 PDA and 109 prostatic acinar adenocarcinoma cases. Prostate-specific antigen density (odds ratio, 3.7; P = .001), cancer grade (odds ratio, 3.3–4.3; P = .02), positive surgical margin (odds ratio, 1.7; P = .02), and tumor volume (odds ratio, 1.3; P = .02) were associated with BCR in multivariable analysis. Prostatic ductal adenocarcinoma, its percentage, intraductal carcinoma, and cribriform Gleason pattern 4 were not significant independent predictors of BCR. Conclusions.— Advanced locoregional stage, higher tumor grade, and positive surgical margin status rather than the mere presence of PDA are more predictive of worse BCR-free survival outcomes following radical prostatectomy in men with a component of PDA.

Palpation Sensitivity of an Embedded Nodule Using the Finite Element Method

A physician palpates a tissue to detect an embedded tumor nodule by sensing an increase in local tissue stiffness and nodule size. The Hertz contact model, however, is unable to predict the material or physical properties of a tumor nodule embedded in a healthy tissue of finite thickness. In this study, utilizing a hyperelastic material model, we propose a general methodology to analyze the extent to which the stiffness, size, and depth of a nodule embedded in a tissue affect its detectability. Using dimensional analysis, we generate simple power-law relations to predict physical and material properties of tumor nodules embedded in healthy tissue during indentation. Our results indicate that indenter radius and indentation depth are critical parameters in nodule detection and a thin indenter and large indentation depth increase detection sensitivity of an embedded tumor nodule. Our results also show that anisotropic material properties of either a tissue or an embedded nodule render the embedded tumor nodule undetectable using indentation. We define palpation sensitivity maps that can be used to predict material and physical properties of tumor nodules in healthy tissues. The analysis and results presented in this study might increase accuracy and precision in instrumented probe-based laparoscopic or robotic surgeries.

Granular Cell Tumor Confined To The Muscularis Propria Of The Appendix: A Case Report

Introduction/Objective Granular cell tumors (GCTs) are exceedingly rare soft tissue tumors that are usually benign and are thought to arise from Schwann cell origin. GCTs most commonly occur in the skin, subcutaneous tissue, and oral cavity. However, they can involve any organ, including the gastrointestinal (GI) tract, of which esophagus is most common, followed by large intestine. We report a case of a 58 year old female who presented with acute appendicitis, followed by an appendectomy to reveal an incidental GCT. Methods This report is a retrospective study of an appendiceal GCT in which we reviewed the case and the histology. In addition, a brief literature review of gastrointestinal GCTs was performed to further elucidate the incidence, location, histopathology, and differential diagnoses for this lesion. Results Histological analysis of the tumor nodule reveals nests of epithelioid cells with abundant granular eosinophilic cytoplasm. The nuclei are bland, small, and round to oval, with rare spindled morphology. Immunohistochemistry for S-100 protein shows diffuse strong cytoplasmic and nuclear positivity, which is suggestive of Schwann cell origin. In the GI tract, GCTs are routinely confined to the mucosa, submucosa, or both; however the tumor nodule in our case is contained within the muscularis propria. Conclusion It is estimated that 5–11% of GCTs occur in the gastrointestinal tract, while only 13 GCT cases of the appendix have been reported. In addition to the previously stated rarity, is the limited involvement of the muscularis propria, with which GCTs typically are not associated. To our knowledge, this is the first confirmed GCT of the appendix that solely involves the muscularis propria, in English medical literature.