Schwannomas are benign, slow-growing peripheral nerve sheath tumors commonly occurring in the head, neck, and flexor regions of the extremities. Although most schwannomas are easily diagnosable, their variable morphology can occasionally create difficulty in diagnosis. Reporting pathologists should be aware that schwannomas can exhibit a broad spectrum of morphological patterns. Clinical and radiological examinations can show correlation and should be performed, in conjunction with ancillary tests, when appropriate. Furthermore, deferring a definitive diagnosis until excision may be necessary for small biopsy specimens and frozen sections. This report underscores these challenges through examination of two unique schwannoma cases, one predominantly cellular and the other myxoid, both of which posed significant challenges in histological interpretation.

Reliable focus is essential for digital cytopathology, yet three-dimensional cell clusters in liquid-based cytology (LBC) slides pose persistent challenges for single-plane whole-slide imaging. We sought to quantitatively compare focus performance among three whole-slide scanners and to evaluate the use of Laplacian variance as an objective focus quality metric. A total of 102,573 image tiles (512 × 512 pixels) were generated from 36 whole-slide images after scanning twelve thyroid LBC slides at 40× magnification using three scanners. Single-plane mode with automatic focusing was applied. Image sharpness for each tile was computed in Python using the variance of the Laplacian, quantified as a focus score and classified into five ordinal categories, ultimately dichotomized as in-focus (variance ≥ 10) versus out-of-focus. Statistical comparisons between scanners were performed. Laplacian variance scores showed strong concordance with visual assessments of focus quality made by pathologists. One scanner consistently achieved the highest median focus scores and the most uniform spatial distribution for SurePath slides, while the other two demonstrated lower median values and greater variability. ThinPrep slides exhibited high focus quality across all scanners (> 95% in-focus), with smaller but still measurable inter-scanner differences. Overall, more than 70% of tiles were in-focus across all scanners, suggesting preserved diagnostic usability. Laplacian variance is a practical and reproducible tool for assessing focus quality in digital cytology. Focus performance varied among scanners, particularly for slides with three-dimensional cell clusters, whereas differences were less pronounced for monolayer ThinPrep preparations. Quantitative focus assessment may support scanner selection, quality assurance, and computational cytopathology workflows.

Monoclonal gammopathy of renal significance is defined as any B cell or plasma cell clonal lymphoproliferation which neither causes tumor complications nor meets any current hematological criteria for specific therapy, with one or more kidney lesions related to the produced monoclonal immunoglobulin, such as amyloidosis. A 50-year-old male presented with heavy proteinuria and blood tests showing IgA and Lambda paraproteinemia. Light microscopy showed mesangial eosinophilic ground substance extending into the capillary loops, and positive staining within the glomeruli and vessel walls for amyloid P immunohistochemistry was also noted. Immunofluorescence showed positive staining for IgA and Lambda in the mesangia and capillary loops. Electron microscopy exhibited organized fibrils measuring 4-5 nm in diameter in the mesangia, glomerular basement membranes and vessel walls. We interpreted the overall findings as atypical renal amyloidosis with IgA and Lambda deposition on immunofluorescence. Further amyloid typing using laser microdissection-liquid chromatography and mass spectrometry will be useful.