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Context.—: Whole-slide imaging has ushered in a new era of technology that has fostered the use of computational image analysis for diagnostic support and has begun to transfer the act of analyzing a slide to computer monitors. Due to the overwhelming amount of detail available in whole-slide images, analytic procedures-whether computational or visual-often operate at magnifications lower than the magnification at which the image was acquired. As a result, a corresponding reduction in image resolution occurs. It is unclear how much information is lost when magnification is reduced, and whether the rich color attributes of histologic slides can aid in reconstructing some of that information., Objective.—: To examine the correspondence between the color and spatial properties of whole-slide images to elucidate the impact of resolution reduction on the histologic attributes of the slide., Design.—: We simulated image resolution reduction and modeled its effect on classification of the underlying histologic structure. By harnessing measured histologic features and the intrinsic spatial relationships between histologic structures, we developed a predictive model to estimate the histologic composition of tissue in a manner that exceeds the resolution of the image., Results.—: Reduction in resolution resulted in a significant loss of the ability to accurately characterize histologic components at magnifications less than ×10. By utilizing pixel color, this ability was improved at all magnifications., Conclusions.—: Multiscale analysis of histologic images requires an adequate understanding of the limitations imposed by image resolution. Our findings suggest that some of these limitations may be overcome with computational modeling.

Cholesterol granuloma is usually associated with chronic middle ear disease and is common in the mastoid antrum and air cells of the temporal bone. It has also been reported in other parts of the skull, such as the frontal and maxillary sinuses and orbit. Cholesterol granuloma is rare in the paranasal sinuses. We report a new case of cholesterol granuloma in the maxillary sinus of a 38-year-old man who underwent surgical excision. We also review the literature and discuss the mechanism of development for this lesion. The resected specimen showed fragments of respiratory mucosa with cholesterol clefts surrounded by multinucleated foreign-body giant cells. Some multinucleated foreign-body giant cells showed asteroid bodies. Hemorrhagic areas, hemosiderin-laden macrophages, chronic inflammatory cells, and dilated lymphatics vessels were seen as well. Increased intrasinus pressure due to drainage obstruction may affect venous and lymphatic drainage from the sinus cavity, leading to venule microhemorrhages while still allowing arterial blood into the sinus mucosa and further contributing to a large localized hemorrhage. Lymphatic drainage may be insufficient to completely remove the lipid components of the red blood cells, and the lipid accumulation may contribute to the formation of cholesterol crystals and their esters.

Background: Lipochrome pigment granules (LPGs) and prostate-specific antigen (PSA) localization have been cited as helpful adjuncts in differentiating atypical histologic patterns of seminal vesicle-ejaculatory duct (SVED) from prostatic adenocarcinoma. However, LPGs have been described in both benign and neoplastic prostatic acini, and PSA expression within the intraprostatic SVED has not been fully explored., Design: Fifty radical prostatectomy specimens were studied for LPGs and 9 cases for PSA expression., Results: Two morphologic types of LPGs (type 1 and type 2) were observed. The reproducibility in classifying LPGs was evaluated by kappa statistics, which demonstrated a strong agreement between 4 observers. Type 1 was restricted to SVED in all 50 specimens. Type 2 was subclassified into 2A and 2B. Type 2 LPGs were observed in prostatic acini of different zones, high-grade prostatic intraepithelial neoplasia, prostatic adenocarcinoma, and occasionally with type 1 LPG in SVED. Focal reactivity for PSA in the distal portion of SVED near urethra was noted in 1 of 9 cases., Conclusion: Awareness about morphologic differences between the 2 types of LPGs could help to avoid a potential diagnostic pitfall of misinterpreting SVED epithelium for adenocarcinoma. Caution is recommended in interpreting PSA expression, since rare focal PSA reactivity was observed in the distal SVED.

Context: The importance of frozen-section diagnoses in the practice of pathology cannot be overemphasized. In some cases, the use of a mucin stain can greatly aid in the diagnosis. Since few methods for mucin staining have been described that can be used in the frozen-section setting, we developed one such staining procedure for mucin., Objective: To develop a rapid mucicarmine staining technique to be used on frozen sections that does not significantly delay overall turnaround time., Design: A standard mucicarmine staining technique was modified by using a concentrated mucicarmine stain and a microwave oven, to reduce the total staining time to 3 minutes or less. Frozen tissue from normal colonic mucosa was used as a control, and skin from extramammary Paget disease for evaluation of margins was used as a case., Results: The rapid mucicarmine stain successfully demonstrated the presence of mucin on frozen-tissue sections. Mucin stained deep rose, and the connective tissue stained green., Conclusion: This rapid and simple mucin staining technique can be used on frozen sections with no significant effect on the overall turnaround time, thereby aiding rapid diagnosis on frozen sections.