Cell blocks in urine cytopathology: do they add value to the diagnosis? A pilot study

Advances in diagnostic liquid-based cytology

Liquid-based cytology (LBC) has changed the landscape of gynaecological cytology. A growing demand exists for LBC in diagnostic cytology, particularly for ancillary testing, such as immunocytochemistry and molecular testing. Ancillary testing solely based on conventional preparation (CP) methods remains challenging. Recently, the increased demand for specialist testing and minimally invasive techniques, such as endoscopic ultrasonography fine-needle aspiration, to obtain cellular samples has led to an increasing demand for ancillary testing on cytology LBC supernatant, slides and cell block (CB). This facilitates the diagnosis and prognosis in cytology samples enabling personalized treatment. An understanding of the history and future prospects of LBC is crucial for its application in routine diagnostics by cytopathologists and cytotechnologists. In this review, we initiated an internet search using the keyword 'liquid-based cytology', and we conducted a literature review to discuss the usefulness of combined diagnosis of LBC and CP, immunocytochemistry and molecular testing and assessed the quality of nucleic acids in diagnostic LBC. High-quality and cell-rich diagnostic LBC surpassed the CP method alone in terms of reliability and versatility of ancillary testing in cytological diagnosis. Conclusively, diagnostic LBC lends itself to various new technologies and is expected to continue evolving with innovations in the future.

Utility and performance of cell blocks in cerebrospinal fluid cytology: Experience at two teaching hospitals

BACKGROUND

Cytology cell blocks (CBs) are not routinely made for cerebrospinal fluid (CSF) specimens. The goal of this study was to identify when CSF CB preparation improves diagnostic performance.

MATERIALS AND METHODS

Under institutional review board approval, a retrospective review of CSF cytology cases was conducted at a tertiary university-based hospital and an affiliated county hospital. Patient history, CSF volume, final diagnosis, use of stains, and whether the CB was contributory was determined from the cytopathology report. CSF nucleated cell count data was obtained from the medical record.

RESULTS

A total of 69 CSF specimens with CBs from January 2006 to March 2023 were identified from 61 patients. The median CSF volume was 8 mL (interquartile range, 4-13 mL; range, 1-800 mL), with immunohistochemical stains performed on 29 (42%) cases. Per cytology report, CB was contributory in 23 cases (33%), not contributory in 34 cases (49%), and not discussed in 12 cases (17%). The median volume was 8 mL for cases in which CB was contributory, not contributory, or not discussed. There was no difference in average nucleated cell counts between cases in which CB was contributory versus not contributory (73.9 vs. 40.0, p = .175).

CONCLUSIONS

CBs for CSF samples were contributory in a subset (33%) of cases. The authors were unable to identify any specific pre-analytic factors, including specimen volume and average nucleated cell counts, for cases in which CB was contributory. Further evaluation is needed to identify if there are scenarios in which CSF CBs should be routinely prepared.

Utility and performance of cell blocks in urine cytology: Experience at three teaching hospitals

BACKGROUND

The use of cell block (CB) preparation is underused in urine cytology (UC) and varies among hospitals. In addition to confirming a diagnosis, CBs can be useful in cases of metastatic disease, diagnoses requiring immunohistochemical (IHC) staining, and for ancillary studies. The role of this study is to examine the performance of CBs for UC at three affiliated teaching hospitals.

MATERIALS AND METHODS

A retrospective review of UC cases with a CB was conducted at a county hospital, Veterans Affairs hospital, and tertiary university-based hospital. For each specimen, patient demographics, specimen type, volume, original diagnosis, and IHC stains were recorded. Each case was reviewed for diagnosis based on ThinPrep alone, diagnosis based on ThinPrep and CB, utility of CB for diagnosis, and CB cellularity.

RESULTS

A total of 250 UC specimens with CB from 186 patients was identified. Bladder washes were the most common (72.1%). IHC stains were performed on 17.2% of cases. On blinded review, CB preparation was deemed useful in 61.2% of cases, with the highest rate for suspicious for high-grade urothelial carcinoma (SHGUC) cases (87.0%). The diagnosis based on ThinPrep review changed with incorporation of CB in 13.2% of cases, with the highest rate for SHGUC cases (43.5%).

CONCLUSIONS

The results demonstrate that use of CB in UC confirms the final diagnosis in more than one-half of cases and changes the diagnosis in a subset of cases. Use of CB was most helpful in the SHGUC category. Further evaluation of the types of cases in which CB are prepared is warranted.

Condyloma acuminatum of the urinary tract demonstrates atypical squamous cells in urine cytology

Urine cytology of urinary tract condylomas has not been systematically studied. We analyzed cytologic features of urinary tract condylomas and evaluated potential diagnostic challenges and pitfalls. We retrospectively reviewed urine cytology of urinary tract condylomas from 2 academic institutions (2015-2022). Among 20 patients with urinary tract condylomas, 6 had urine cytology (2 samples in 1 patient), including 3 men and 3 women (mean age, 74.3 years; range, 65-86 years). Original interpretations were negative for high-grade urothelial carcinoma (NHGUC; n = 4), atypical urothelial cells (n = 1), reactive urothelial cells (n = 1), and negative for malignancy (n = 1). Squamous cells were noted in 3 cases, atypical squamous cells (ASC) consistent with low-grade squamous intraepithelial lesion (LSIL) were noted in 1 case, and in 3 cases, the presence of squamous cells was not mentioned. All urines were reclassified according to The Paris System as NHGUC. Specimens were composed of benign urothelial cells and groups or isolated ASC consistent with LSIL (n = 4), atypical keratinized squamous cells (n = 2), and ASC that did not meet LSIL criteria (n = 1). The LSIL cells showed nuclear enlargement (n = 4), hyperchromasia (n = 4), perinuclear halo (n = 3), nuclear membrane irregularity (n = 4), orangeophilic cytoplasm (n = 3), and binucleation (n = 4). The atypical keratinized squamous cells showed hyperchromasia (n = 2), nuclear membrane irregularity (n = 2), keratin pearls (n = 2), and binucleation (n = 1). The ASC that did not meet LSIL criteria showed nuclear enlargement and orangeophilic cytoplasm. Many urinary tract condylomas (57%) demonstrate classic LSIL features in urine cytology. Less frequent cases can mimic keratinizing squamous cell carcinoma (28%) or demonstrate ASC not diagnostic of LSIL (15%).

The Diagnostic Dilemma of Urothelial Tissue Fragments in Urinary Tract Cytology Specimens

Since the release of The Paris System for Reporting Urinary Cytology (TPS), the assessment of urine cytology specimens has primarily focused on the detection of high-grade urothelial carcinoma (HGUC) and carcinoma in situ (CIS). Fortunately, the malignant cells in these lesions tend to be loosely cohesive, resulting in the natural exfoliation of individual malignant cells into the urine. However, HGUC/CIS lesions occasionally exfoliate larger fragments which can be difficult to assess due to cellular overlap and fragment three-dimensionality. Furthermore, reactive benign urothelial fragments and fragments from low-grade urothelial neoplasms (LGUN) may also be seen in urine specimens and contain atypical cytomorphologic features. As a result, the significance of urothelial tissue fragments (UTFs) is often unclear. Herein, we discuss the literature on UTFs before and after the implementation of TPS, as well as strategies to help overcome this diagnostic challenge.

CelLock TM: an innovative standardized cell-block preparation procedure

The CelLock™ procedure kit is used to collect and prepare cellular specimens such as fine needle aspirates (FNA), cytology specimens, cultured cells, small tissue biopsies, and samples with scant tissue fragments or cells into a paraffin cell-block. This cell-block can be used for subsequent microtomy and staining using hematoxylin and eosin (H&E), special stains, immunohistochemistry (IHC), and applicable molecular techniques such as in situ hybridization (ISH). CelLock is a standardized method that provides optimal receipt, preservation, preparation, and processing of cell-blocks which, contain virtually all of the submitted specimens and are able to be embedded and sectioned in a reproducible fashion. The specimen contained within the cell-block is preserved such that all the cellular protein and genetic information is available for histological and ancillary testing.