A Pilot Study Evaluating Fine-Needle Aspiration Cytology of Clear-Cell Renal Cell Carcinoma: Comparison of Ancillary Immunocytochemistry and Cytomorphological Characteristics of SurePath™ Liquid-Based Preparations with Conventional Smears

Adult Renal Neoplasms: Cytology, Immunohistochemistry, and Cytogenetic Characteristics

Tissue sampling of renal masses is traditionally performed using percutaneous sonographic or CT guidance core biopsy (CB) with or without touch preparation cytology and/or fine-needle aspiration cytology (FNAC). The combined used of CB and FNAC is expanding in clinical practice, especially in small renal masses and plays a pivotal role in therapeutic decision making. Grouping the renal neoplasms in differential diagnostic groups helps in choosing specific immunohistochemical markers and reaching an accurate diagnosis.

Quantitative Proteomic Analysis Identifies AHNAK (Neuroblast Differentiation-associated Protein AHNAK) as a Novel Candidate Biomarker for Bladder Urothelial Carcinoma Diagnosis by Liquid-based Cytology

Cytological examination of urine is the most widely used noninvasive pathologic screen for bladder urothelial carcinoma (BLCA); however, inadequate diagnostic accuracy remains a major challenge. We performed mass spectrometry-based proteomic analysis of urine samples of ten patients with BLCA and ten paired patients with benign urothelial lesion (BUL) to identify ancillary proteomic markers for use in liquid-based cytology (LBC). A total of 4,839 proteins were identified and 112 proteins were confirmed as expressed at significantly different levels between the two groups. We also performed an independent proteomic profiling of tumor tissue samples where we identified 7,916 proteins of which 758 were differentially expressed. Cross-platform comparisons of these data with comparative mRNA expression profiles from The Cancer Genome Atlas identified four putative candidate proteins, AHNAK, EPPK1, MYH14 and OLFM4. To determine their immunocytochemical expression levels in LBC, we examined protein expression data from The Human Protein Atlas and in-house FFPE samples. We further investigated the expression of the four candidate proteins in urine cytology samples from two independent validation cohorts. These analyses revealed AHNAK as a unique intracellular protein differing in immunohistochemical expression and subcellular localization between tumor and non-tumor cells. In conclusion, this study identified a new biomarker, AHNAK, applicable to discrimination between BLCA and BUL by LBC. To our knowledge, the present study provides the first identification of a clinical biomarker for LBC based on in-depth proteomics.

Atypical Histiocytoid Cells in Metastatic Papillary Thyroid Carcinoma: An Underrecognized Cytologic Pattern

OBJECTIVES

Fine-needle aspiration (FNA) of head and neck lymph nodes (LNs) is useful in diagnosing metastatic papillary thyroid carcinoma (PTC) and most commonly shows classic cytologic features of PTC. Metastatic PTC, however, may occasionally present with a pattern unfamiliar to most pathologists: atypical histiocytoid cells (AHCs).

METHODS

All PTC thyroidectomy specimens with associated FNA of LNs were retrieved from our files for 2007 to 2013. We aimed to assess cytologic features of metastatic PTC, as well as the presence of AHCs and their morphology.

RESULTS

Fifty-six FNAs from LNs with metastatic PTC were reviewed. AHCs were identified in 38 (68%) cases, while only PTC with classic cytologic features was seen in 18 (32%) cases. AHCs did not show diagnostic nuclear features of PTC and presented as large cells with abundant cytoplasm either vacuolated or dense. Nuclei varied from vesicular with prominent nucleoli to dark and smudgy. Thirty-one cases showed mixed AHCs and classic PTC, but seven cases (13% of all metastatic PTCs in LNs) consisted only of AHCs.

CONCLUSIONS

AHCs are an often unrecognized metastatic morphologic pattern of cystic PTC, as it does not show diagnostic classic nuclear features of PTC. AHCs are the predominant cytologic finding in approximately 13% of metastatic PTCs to neck LNs.

Smears are important for adequate cytologic diagnosis of kidney lesions

INTRODUCTION

Traditionally at our institution, smears with or without liquid-based cytology (LBC) and core biopsies (CBs) have been obtained by radiologists performing image-guided fine-needle aspiration biopsies (FNABs) of deep organs. Since 2015, however, there has been a shift to providing cytology with samples for LBC only when obtaining CBs. The impression among our institution's cytologists is that LBC alone is less often adequate for diagnosis compared with smears and LBC together. We examined a series of kidney FNABs pre- and post-"LBC only" to evaluate this impression.

MATERIALS AND METHODS

With institutional review board approval, we compared all kidney FNABs from 2012 to those from 2015. We recorded the type(s) of cytology preparation(s), the number of cytology slides, the cytology diagnosis, the concurrent CB diagnosis, and whether there was a subsequent excision and the excision diagnosis. We examined cytology and CB slides as needed.

RESULTS

In 2012, 105 patients underwent 111 kidney biopsies, 109 with smears made. In 2015, 58 patients underwent 62 kidney biopsies, 7 with smears made. In 2012, there were 13 (12%) nondiagnostic (ND) cytology cases and 19 (17%) cases where the cytology and CB diagnoses were discrepant. By comparison, in 2015, there were 20 (32%) ND cytology cases and 21 (33%) discrepant cases.

CONCLUSIONS

There were more cytology slides per case and fewer ND diagnoses in 2012 compared with 2015 (12% versus 32%, respectively, P = 0.001). Concordance was also better in 2012 (83% versus 67%, P = 0.015). We believe that our metrics would improve if we returned to the procedures followed in 2012.