Characteristic morphology and immunohistochemical patterns of clear cell papillary renal cell tumours may be observed in renal cell carcinomas, a critical pitfall in renal biopsy cytopathology.

BACKGROUND: Clear cell papillary renal cell tumour (CCPRCT) was renamed from previous clear cell papillary renal cell carcinoma (CCPRCC) in the latest WHO Classification of Tumours. It is essential to differentiate RCC from CCPRCT in renal mass biopsies (RMB). DESIGN: RMB cases with subsequent resections were reviewed. The pathology reports and pertinent clinical information were recorded. RESULTS: Fifteen cases displaying either CCPRCT morphology (20% diffuse, 67% focal) or immunohistochemical patterns (cup-like CA9: 20% diffuse, 47% focal; CK7: 33% diffuse, 40% focal) were identified. One case was positive for TFE3. TSC mutation was identified in one case. Both cases exhibited both CCPRCT morphology and immunohistochemical patterns for CA9 and CK7, with focal high-grade nuclei. RMB diagnoses were as follows: 6 (40%) as CCRCC, 2 (13%) as CCPRCT, 2 (13%) as CCRCC versus CCPRCT, 2 (13%) as CCRCC versus PRCC, 1 (7%) as RCC with TSC mutation versus CCPRCT, 1 (7%) as TFE3-rearranged RCC versus PRCC, and 1 (7%) as cyst with low-grade atypia. 71% of patients underwent nephrectomy, 21% received systemic treatment for stage 4 RCCs, and 7% with ablation for small renal mass (1.6 cm) with low-grade CCRCC. CONCLUSIONS: Our study highlights that morphologic and immunochemical features of CCPRCT may be present in RCCs, including RCC-TFE3 expression and TSC-associated RCC, a critical pitfall to misdiagnose aggressive RCC as indolent CCPRCT and result in undertreatment. Careful examination of morphology and immunostains for CA9, CK7, and TFE3, as well as molecular tests, is crucial for distinguishing aggressive RCC from indolent CCPRCT.

Fusion of old and new: Employing touch imprint slides for next generation sequencing in solid tumors.

BACKGROUND: Cytomorphological evaluation of tissue touch imprints during rapid on-site evaluation or intraoperative pathology consultation has crucial value. However, literature on their utility for molecular testing is limited. In this study, we emphasize a further benefit of touch imprint slides and scrutinize our institutional experience on their use in molecular testing, specifically next generation sequencing (NGS). MATERIALS AND METHODS: NGS-based reports (2019-2023) of Koç University Hospital were retrospectively analyzed and circumstances in which sequencing was conducted on touch imprint slides were retrieved (n = 18). Type/location of the biopsy, diagnosis, results, and quality metrics were recorded. RESULTS: Touch imprints were addressed when they harbored more neoplastic cells compared with permanent biopsies, when suboptimal fixation mitigated deoxyribonucleic acid/ribonucleic acid (DNA/RNA) yield in resections or when the sample was obtained from bone and required decalcification. Diagnoses were diverse, namely non-small-cell lung cancer, gastric adenocarcinoma, glial tumor, Ewing sarcoma, and carcinoma of unknown primary. The percentage of tumor cells on slides stretched between 15% and 70%. Molecular findings ranged from KRAS mutations to TRIM1::NTRK2 and EWSR::FLI1 fusions. For five cases, sequencing did not yield any alteration, one study was not completed because it did not yield high-quality RNA. CONCLUSION: Touch imprint slides provide a reliable alternative, especially when neoplastic cells are scarce in permanent biopsies or decalcification deters nucleic acid quality. Based on our experience, we suggest making touch imprints on a routine basis, especially for every bone biopsy. Once digitally scanned duplicates are made, original slides can be safely used for DNA-/RNA-based molecular studies.

Cytomorphology of papillary renal neoplasm with reverse polarity.

Papillary renal neoplasm with reverse nuclear polarity (PRNRP) is an emerging oncocytic renal tumor. Cytomorphologic features of this tumor have not been described in the literature before. The objective of this study was to review the cytomorphology of a case PRNRP and compare with cytomorphologic features of papillary renal cell carcinomas (pRCCs) reported in the literature. 1 case of core needle biopsy (CNB) with touch preparation (TP) of a renal mass diagnosed as PRNRP was reviewed retrospectively. Clinical presentation, cytomorphologic features, ancillary tests and histopathology results were analyzed. The touch preparation was cellular and showed tight 3-D clusters of cuboidal epithelial cells with variable presence of fibrovascular cores (FC), granular eosinophilic cytoplasm, round apically located grade 1 nuclei compared to cases of pRCC that consistently showed presence of FCs lined by cuboidal to columnar epithelial cells with variable degree of cytologic atypia. Features characteristic of pRCC like foamy macrophages, hemosiderin laden macrophages, nuclear grooves or psammoma bodies were not present. No necrosis or mitosis were identified. By immunohistochemistry (IHC) the tumor cells were positive for cytokeratin 7, GATA-3 and AMACR (focal) and negative for CA-IX, CD117 and vimentin. Cytomorphologic features of PRNRP are unique and characterized by tight 3-D clusters (with or without FCs) of cuboidal cells with small round apically located nuclei and finely granular oncocytic cytoplasm. Specific diagnosis of PRNRP on cytology or CNB is feasible along with use of ancillary tests IHC and /or molecular tests.

Cytologic features of gynecologic germ cell tumors and carcinomas exhibiting germ cell tumor differentiation.

BACKGROUND: In this study, the authors sought to describe the cytologic features of primary gynecologic germ cell tumors and carcinomas exhibiting germ cell differentiation because little information currently exists. METHODS: An institutional database search was performed to identify histologically confirmed gynecologic germ cell tumors and carcinomas with germ cell tumor differentiation. Available cytologic material was reviewed by three observers, and morphologic features were recorded in addition to patient age at original diagnosis, primary tumor site, site(s) from which the examined cytologic material was obtained, and the type of examined cytologic preparations. RESULTS: In total, 15 cytologic specimens from 12 women (aged 19-82 years) were identified and included touch preparations of core biopsies from various sites (n = 6), fine-needle biopsies (n = 2), pelvic washings (n = 1), ascitic fluids (n = 4), pelvic cyst fluid (n = 1), and endometrial aspirate (n = 1). Of the 12 patients, seven had primary gynecologic germ cell tumors, four had gynecologic (ovarian and endometrial) tumors exhibiting somatic yolk sac tumor-like differentiation, and the remaining patient had an intestinal-type adenocarcinoma arising within an ovarian teratoma. There was morphologic overlap among many of the cases, although cytoplasmic vacuolation/granular cytoplasm was seen in 75% of primary yolk sac tumors or carcinomas with yolk sac tumor differentiation, and dense/squamoid cytoplasm was seen in 100% of teratomatous elements that were sampled. CONCLUSIONS: Germ cell tumors and somatic neoplasms exhibiting germ cell tumor differentiation occurring in adult women share some cytologic features and may be difficult to distinguish from one another, although some tumor types showed characteristic cytomorphologic findings.

Minimally invasive cytologic evaluation leading to the diagnosis of TFE3-rearranged renal cell carcinoma: A case report.

TFE3-rearranged renal cell carcinoma (RCC) has been categorized as a molecularly defined renal carcinoma in the 2022 WHO classification of tumors as it does not demonstrate a specific genotype-phenotype correlation. However, in order to arrive at the diagnosis, recognition of the broad spectrum of cytologic and histologic features that can be seen in TFE3-rearranged RCC is important for differential diagnostic consideration. Reported here is the diagnostic workup of a TFE3-rearranged RCC using very limited tissue sample. The initial evaluation was dependent on the cytomorphologic findings observed on a touch preparation made from the renal mass biopsy, directing appropriate selection of ancillary tests, and leading to a definitive diagnosis.

Predicting malignant pleural effusion during diagnostic pleuroscopy with biopsy: A prospective multicentre study.

BACKGROUND AND OBJECTIVE: Pleuroscopy with pleural biopsy has a high sensitivity for malignant pleural effusion (MPE). Because MPEs tend to recur, concurrent diagnosis and treatment of MPE during pleuroscopy is desired. However, proceeding directly to treatment at the time of pleuroscopy requires confidence in the on-site diagnosis. The study's primary objective was to create a predictive model to estimate the probability of MPE during pleuroscopy. METHODS: A prospective observational multicentre cohort study of consecutive patients undergoing pleuroscopy was conducted. We used a logistic regression model to evaluate the probability of MPE with relation to visual assessment, rapid on-site evaluation (ROSE) of touch preparation and presence of pleural nodules/masses on computed tomography (CT). To assess the model's prediction accuracy, a bootstrapped training/testing approach was utilized to estimate the cross-validated area under the receiver operating characteristic curve. RESULTS: Of the 201 patients included in the study, 103 had MPE. Logistic regression showed that higher level of malignancy on visual assessment is associated with higher odds of MPE (OR = 34.68, 95% CI = 9.17-131.14, p < 0.001). The logistic regression also showed that higher level of malignancy on ROSE of touch preparation is associated with higher odds of MPE (OR = 11.63, 95% CI = 3.85-35.16, p < 0.001). Presence of pleural nodules/masses on CT is associated with higher odds of MPE (OR = 6.61, 95% CI = 1.97-22.1, p = 0.002). A multivariable logistic regression model of final pathologic status with relation to visual assessment, ROSE of touch preparation and presence of pleural nodules/masses on CT had a cross-validated AUC of 0.94 (95% CI = 0.91-0.97). CONCLUSION: A prediction model using visual assessment, ROSE of touch preparation and CT scan findings demonstrated excellent predictive accuracy for MPE. Further validation studies are needed to confirm our findings.

Molecular Imaging of HER2 in Patient Tissues with Touch Prep-Quantitative Single Molecule Localization Microscopy.

Biomolecules can be investigated at the nanoscale with quantitative single molecule localization microscopy (qSMLM). This technique, which achieves single molecule sensitivity, can probe how membrane receptors are organized under both normal and pathological conditions. While a number of receptors have been extensively studied in cultured cells, technical challenges have largely impeded their robust quantification in tissue samples. To rigorously interrogate tissue samples, methodological advancements are needed in three areas: analytical preparation of the sample, proper characterization of fluorescent reporters, and rapid/unbiased data analysis. Towards these ends, we have combined qSMLM with a touch preparation technique (touch prep-qSMLM). In this new method, touch prep is first used to obtain monolayers of patient cells. Then, highly selective, fluorescently labeled probes are used to detect the receptors of interest on the plasma membranes of cells. Finally, quantitative algorithms are used to analyze the imaging data. Using this touch prep-qSMLM methodology, we interrogated the density and nano-organization of human epidermal growth factor receptor 2 (HER2) in fresh breast cancer tissues. Touch prep-qSMLM agreed well with current clinical methods. Importantly, touch prep-qSMLM can be easily extended to other pathological conditions and ultimately used in precision medicine.

Cytologic features of small cell melanoma.

Small cell melanoma (SCM) is an aggressive variant of malignant melanoma (MM), which has been rarely described in the cytology literature. The aim of this study was to describe the clinical and cytologic features of a series of cases of metastatic SCM with discussion of the differential diagnosis of metastatic SCM diagnosed by fine-needle aspiration (FNA). A retrospective review of cases was performed, identifying two FNA cases and one core biopsy with touch preparation of metastatic SCM. Clinical presentation, cytomorphology features, ancillary tests, and final diagnoses were documented and analyzed. Patients ranged in age from 69 to 85 years-old. Cytomorphologic features included the presence of a monomorphic population of dispersed small round blue cells, with scant cytoplasm, high nuclear to cytoplasmic ratios, dense nuclear chromatin, and inconspicuous nucleoli. Acinar like arrangement (n = 2) and nuclear molding (n = 1) were also present. All cases showed diffuse positivity for the melanocytic markers SOX10 and Melan A by immunohistochemistry (IHC). Expression of neuroendocrine markers was variable. Diagnosing metastatic SCM at unusual anatomic sites by FNA cytology is a challenging task, especially in patients without known prior history of melanoma. Cytomorphology of SCM is unique, differing from conventional MM in many aspects, including the presence of acinar formations and a lack of typical melanoma features, such as large cells, intracytoplasmic melanin, and macronucleoli. IHC is critical for establishing the diagnosis of SCM.

To whom the specimen goes: a look at how touch preparations and core needle biopsies are handled in different practices and the effect on fellowship education.

INTRODUCTION: Core needle biopsies (CNBs) have proven to be an excellent source of tissue for diagnosis and ancillary testing in the era of personalized medicine, commonly yielding sufficient material for testing via a relatively minimally invasive technique. Thus, there has been an increase in touch preparations (TPs) evaluated with rapid onsite evaluation (ROSE) of these small biopsies either in isolation or with concurrent fine needle aspiration (FNA). This in turn has forced cytopathology practices to make decisions with regard to processing and workflow of CNBs, which affects cytopathology fellowship education substantially. STUDY DESIGN: The present review is based on a review of recent literature and an evaluation of the authors' personal experiences. RESULTS AND CONCLUSIONS: Deciding whether CNBs with associated TPs should be assigned to the cytology service, the subspecialty or general surgical pathology service, or a split between cytopathology and surgical pathology, is complicated. The workflow is variable at different institutions depending on multiple factors. Each of these routes has benefits and disadvantages that can affect patient care and laboratory workflow, in addition to having downstream effects on the quality and type of education our pathology trainees receive. Herein, the advantages and disadvantages of the different approaches for CNB triage are discussed, with an emphasis on the impact upon cytopathology fellowship education.

Cytomorphologic analysis of clear cell papillary renal cell carcinoma: Distinguishing diagnostic features.

BACKGROUND: Clear cell papillary renal cell carcinoma (CCPRCC) shares histomorphologic and immunophenotypic features with clear cell RCC (CCRCC) and papillary RCC (PRCC). METHODS: We compared the cytomorphology, immunoprofile, and clinical management of CCPRCC (n = 18), CCRCC (n = 20), and PRCC (n = 18). RESULTS: Useful cytomorphologic features for comparing CCPRCC with CCRCC include 3-dimensional clusters (72% vs 0%), papillae (50% vs 0%) and sheets (22% vs 70%), vasculature (papillary vs traversing), naked nuclei (17% vs 100%), prominent nucleoli (0% vs 65%), and amount of cytoplasm (small vs large). Useful cytomorphologic features for comparing CCPRCC with PRCC include sheets (22% vs 61%), naked nuclei (17% vs 67%), nuclear grooves (5% vs 67%) and inclusions (17% vs 67%), and pigmented cytoplasm (17% vs 83%). At on-site evaluation, 16 of 18 (86%) CCPRCC specimens were deemed adequate, with suspicion for CCPRCC in 5 of 16 (31%) cases. Core histology of CCPRCC showed low-grade malignant cells in nests (67%), tubules (100%), and papillae (72%), frequently in myxohyaline stroma (67%). Immunostains demonstrated expression of cytokeratin 7 (CK7; 100%), carbonic anhydrase IX (CA IX; 100%, cup-like), CD10 (53%, reverse cup-like), and α-methylacyl-CoA racemase (AMACR; 35%). Among 18 CCPRCC patients, 9 (50%) underwent nephrectomy, 5 (28%) underwent cryo-ablation, and 4 (22%) were under surveillance with serial imaging. CONCLUSION: Certain morphologic features represent diagnostic criteria of CCPRCC in cytology specimens and help distinguish CCPRCC from CCRCC and PRCC. Immunostaining patterns with CK7, CA IX, CD10, and AMACR can confirm the diagnosis. Delineating CCPRCC from more biologically aggressive RCC types in cytology specimens enhances presurgical and clinical management of patients given CCPRCC's low-grade, indolent behavior.

The Sensitivity and Specificity of Touch Preparation for Rapid Diagnosis of Invasive Fungal Sinusitis: A Pilot Study.

Invasive fungal sinusitis is a morbid pathology that typically affects immunocompromised patients and may quickly progress to fulminant disease. The purpose of this study was to measure the sensitivity and specificity of touch preparation of nasal debridement specimens as a rapid diagnostic tool for invasive fungal sinusitis. A retrospective chart review was performed of 22 patients undergoing nasal debridement due to suspicion for invasive fungal sinusitis over a 10-year period. Thirteen patients had touch preparation of nasal specimens followed by routine histologic processing; two of these patients underwent 2, and 1 patient had 3 separate debridements, for a total of 17 touch preparations performed. The sensitivity and specificity of touch preparation were calculated by correlating the initial results with the presence of fungal invasion on final pathologic analysis. The sensitivity of touch preparation was 56% (95% confidence interval [CI]: 0.23-0.85), specificity was 100% (95% CI: 0.60-1.00), positive predictive value was 100% (95% CI: 0.46-1.00), and negative predictive value was 67% (95% CI: 0.35-0.89). This procedure may be a useful adjunct in situations requiring rapid diagnosis of invasive fungal sinusitis but should not be used as the sole criteria for determining the need for surgical intervention.

An update on touch preparations of small biopsies.

Touch preparations (TPs) are being increasingly utilized in the era of personalized medicine. They fill a gap in cytopathology practice by providing a method to perform rapid onsite evaluation of small tissue samples such as core needle biopsies. However, there is a paucity of literature about how best to perform and interpret a TP. A high-quality TP can provide excellent diagnostic accuracy and good concordance with core needle biopsy histopathology findings. Although many of the cytomorphologic features of TPs overlap with fine needle aspirate smears, TP cytology is unique and differs from conventional smears in many aspects. It is important for cytologists to recognize these features, as well as potential pitfalls and artifacts in order to avoid misinterpretation. Core depletion of tumor cells is a notable drawback if TPs are performed too aggressively. TP slides are also valuable for ancillary testing because they often contain a cellular and pure population of whole tumor cells. This paper reviews all of the aspects of TPs including their clinical utility, proper slide preparation techniques, distinctive cytomorphologic characteristics, limitations, and potential pitfalls.

A prospective analysis of touch preparation cytology for intraoperative detection of mediastinal lymph node metastases.

INTRODUCTION: Patients diagnosed with lung cancer may require immediate evaluation of mediastinal lymph nodes to determine treatment plan. Typically, frozen section (FS) analysis has been used, but this analysis can be time-consuming and uses more tissue than touch preparation (TP) cytologic analysis. TP accuracy has been studied in other organs, but no prospective studies comparing TP to FS have been performed on mediastinal lymph nodes in lung cancer. Our goal was to compare the accuracy of TP to FS in these cases. MATERIALS AND METHODS: After obtaining institutional review board approval, all patients undergoing mediastinal lymph node evaluation for a diagnosis of lung cancer were asked to participate. If consent was given, TP and FS analyses were performed on all mediastinal lymph node stations in all patients and compared to permanent hematoxylin and eosin analysis. Data were collected prospectively. RESULTS: Twenty patients were enrolled. Mean age was 67.7 years. Fifty-five percent (11 of 20) of patients were men. The mean number of lymph node stations sampled in each patient was 3.4. In predicting the stage of the patient, TP had a sensitivity and specificity of 95% and 100%, respectively. FS had a lower sensitivity, 85%, and a specificity of 100%. On permanent analysis, metastatic foci ranged in size from 0.15 mm to 1.5 mm. CONCLUSIONS: TP was more sensitive than FS in detecting mediastinal lymph node metastases. The technical difficulty of obtaining full-thickness sections without creating significant artifact may contribute to the lower sensitivity of FS in detecting micrometastases.

Improving ROSE: Discrepant touch preparation and histology findings in cytology of renal masses: A 10-year retrospective review.

BACKGROUND: The number of "renal incidentalomas" is on the rise due to increasing use of radiologic studies. Image-guided core needle biopsies (CNB) with touch preparations are performed to guide specimen collection and triage of sample for additional studies. Results allow the clinical team to make appropriate treatment decisions. DESIGN: Our electronic database was searched for a 10-year period to identify 180 image-guided biopsies of renal masses with rapid on-site evaluations (ROSE) and corresponding biopsy/resection specimens. Touch preparations were classified as non-diagnostic, negative/benign, adequate/positive for malignancy/oncocytic predominance, or atypical. These results were compared to the final diagnosis on the biopsy or resection specimen (if available). Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values were determined. Non-diagnostic cases and cases in which ROSE and final diagnosis were discordant were reviewed by cytopathologists blinded to the original interpretation to reconcile discrepancies and highlight interpretation pitfalls. RESULTS: A ROSE diagnosis was rendered in 133 of 180 cases; 47 cases were non-diagnostic. Of the 133 diagnostic cases, the ROSE diagnosis was concordant with the core biopsy final diagnosis in 125 cases, yielding a diagnostic accuracy of 94%. The overall sensitivity was calculated to be 80.1%; specificity 72.4%; positive predictive value 94%; and negative predictive value 41.2%. CONCLUSIONS: Touch preparation slides are vital but imperfect tools in evaluating renal masses. In our study, distinction between malignant and benign samples was accomplished in most cases (94% accuracy), but there are limitations. Awareness of interpretation pitfalls allows informed decisions to be made regarding specimen collection and patient management.

Contrast-induced nephropathy in an animal model: Evaluation of novel biomarkers in blood and tissue samples.

Identification of novel biomarkers of contrast-induced nephropathy (CIN) that may more accurately detect renal function changes; reflect kidney damage; assist monitoring; and elucidate pathophysiology attract considerable scientific attention nowadays. To evaluate novel biomarkers of nephrotoxicity in blood/tissue samples of a CIN model, 10 New Zealand white rabbits were divided into group 1 (n = 5; iopromide) and group 2 (n = 5; control). Blood was drawn at 0 h (immediately), 24 h and 48 h after contrast medium (CM) administration. Animals were euthanized at 48 h and kidneys were removed. Serum creatinine (sCr)/symmetric-asymmetric dimethylarginine (SDMA-ADMA) levels were measured. CM genotoxic/cytotoxic effect was investigated 48 h post-CM exposure using micronucleus assay in lymphocytes. Cytological examination was conducted using touch preparation technique (TPT). All animals in group 1 developed CIN: mean sCr levels increased by 68.2% within 48 h. Significant SDMA-ADMA level elevation was observed at 0 h and 24 h with insignificant drop at 48 h in group 1, remaining normal in group 2 at all time-points. Significant increase in bi-nucleated cells with micronuclei and micronuclei frequency was detected in group 1. Cytokinesis block proliferation index was reduced insignificantly in group 1. TPT revealed degenerative lesions/inflammation, cell degeneration, abnormal uterine tubular casts and rubella in kidneys of all animals in group 1. Group 2 presented normal cells.

Intraoperative Squash and Touch Preparation Cytology of Brain Lesions Stained with H+E and Diff-Quik™: A 20-Year Retrospective Analysis and Comparative Literature Review.

OBJECTIVE: Squash preparation (SP) is a rapid technique for the intraoperative assessment of brain lesions. Only a few studies have employed touch preparation (TP) cytology and Diff-QuikTM (DQ) staining in conjunction with SP. Our study aimed to assess the diagnostic efficacy of SP of brain lesions at our institution, ascertain the additional effect of TP and DQ staining, examine factors affecting the sensitivity and specificity of our methods, and compare our findings with those of previous investigations. STUDY DESIGN: Our database was searched for all SP/TP of brain lesions examined from January 1996 to December 2016. RESULTS: During this 20-year study period, our search revealed 400 brain lesions diagnosed by SP/TP cytology. There were 338 (84.5%) neoplasms and 62 (15.5%) nonneoplastic lesions. The most common neoplasms were glioblastoma multiforme (24.6%), metastatic cancer (18.3%), meningioma (16.9%), astrocytoma (11.5%), lymphoma (8.3%), oligoastrocytoma (3.3%), and pituitary adenoma (3.3%). There was discordance between the SP/TP and histological diagnoses in 19/338 (5.6%) cases, i.e., 12 misclassifications of tumor subtype and 7 sampling errors. No false-positive cases were detected. CONCLUSION: Brain SP/TP stained with H+E/DQ demonstrated high sensitivity (97.9%), specificity (100%), and overall diagnostic accuracy (95.3%). The combined methods, in particular, aided in the diagnosis of brain tumors prone to smearing artifacts and certain metastatic malignancies.