Walid E. Khalbuss

A comparison of EGFR and KRAS status in primary lung carcinoma and matched metastases.

Epidermal growth factor receptor (EGFR) and v-Ki-ras 2 (KRAS; viral Kirsten rat sacoma 2 oncogene homolog) oncogenes are predictors of response to EGFR-targeted therapy in lung carcinomas. Morphologic heterogeneity of lung carcinomas is reflected at the molecular level and may confound interpretation of immunohistochemistry, fluorescence in situ hybridization, and mutational assays, which are all used for analysis of KRAS and EGFR genes. Furthermore, molecular characteristics may differ between the primary tumor and corresponding metastases. The aim of this study was to determine if the KRAS and/or EGFR status of primary and metastatic lung carcinoma differs. Three hundred thirty-six cases of primary lung carcinomas were tested for EGFR and KRAS, and 85 cases had a metastasis (25%). Of the 40 cases (47%) with sufficient material for EGFR and KRAS mutational analysis, there were 11 (27.5%) primary tumors and 4 (10%) metastases identified with a KRAS mutation. Of the cases with EGFR fluorescence in situ hybridization results, there were 3 (8%) primary tumors and 8 (24%) metastases that were fluorescence in situ hybridization positive. Overall, there were 9 cases (22.5%) with discordant KRAS status and 11 cases (32.5%) with discordant EGFR fluorescence in situ hybridization status. Our results suggest that the EGFR and KRAS status of primary lung carcinomas may not predict the status in the corresponding metastases. This observation may have important implications for molecular testing for targeted therapies.

The cytological features of mammary analogue secretory carcinoma: a series of 6 molecularly confirmed cases.

Mammary analogue secretory carcinoma (MASC) of the salivary glands is a newly described tumor entity associated with the t(12;15)(p13;q25) ETV6‐NTRK3 translocation. Early studies have shown this tumor to be a distinct entity with histologic, biologic, and clinical differences from acinic cell carcinoma and adenocarcinoma, not otherwise specified. Because this tumor was described only recently, it remains relatively unknown outside of head and neck specialty pathology centers.

Indeterminate Pediatric Thyroid Fine Needle Aspirations: A Study of 68 Cases

Objective: The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) provides a reporting scheme for thyroid fine needle aspiration (FNA) and includes three indeterminate categories with different management strategies. This study analyzes indeterminate thyroid FNAs in children, and correlates these findings with the histological features. Methods: A total of 179 thyroid FNA specimens were retrieved from children. Cases were categorized by TBSRTC. Only cases diagnosed as atypia (AUS)/follicular lesion of undetermined significance (FLUS), suspicious for follicular or oncocytic neoplasm (SFON), or suspicious for malignancy (SM) were selected and correlated with the nodule size and histological follow-up. Results: Sixty-eight cases were identified, including 43 (63%) AUS/FLUS diagnoses, 19 (28%) SFON, and 6 (9%) SM. On follow-up, 48% were malignant, including 28% AUS/FLUS cases, 58% SFON, and 100% SM. The average size of the malignant lesions diagnosed preoperatively as AUS/FLUS was 1.5 cm (range 0.7-4.5), compared to 3.3 cm (range 1.2-6.6) in SFON and 2.8 cm (range 0.7-3.8) in SM. Malignancies included 92% papillary thyroid carcinoma (PTC), 77% of which were the follicular variant of PTC (FVPTC) and 8% follicular carcinomas. The AUS/FLUS cases were largely due to compromised specimens (49%) and the highest malignancy rate occurred in those with cytological atypia (50%). Conclusions: This study shows an incremental risk of malignancy within the indeterminate categories using TBSRTC in children. Malignant nodules with a preoperative AUS/FLUS diagnosis tended to be smaller than those with a SFON or SM diagnosis, and the vast majority of malignancies were PTC, with a high proportion being FVPTC.

Digital Imaging in Cytopathology

Rapid advances are occurring in the field of cytopathology, particularly in the field of digital imaging. Today, digital images are used in a variety of settings including education (E-education), as a substitute to multiheaded sessions, multisite conferences, publications, cytopathology web pages, cytology proficiency testing, telecytology, consultation through telecytology, and automated screening of Pap test slides. The accessibility provided by digital imaging in cytopathology can improve the quality and efficiency of cytopathology services, primarily by getting the expert cytopathologist to remotely look at the slide. This improved accessibility saves time and alleviates the need to ship slides, wait for glass slides, or transport pathologists. Whole slide imaging (WSI) is a digital imaging modality that uses computerized technology to scan and convert pathology and cytology glass slides into digital images (digital slides) that can be viewed remotely on a workstation using viewing software. In spite of the many advances, challenges remain such as the expensive initial set-up costs, workflow interruption, length of time to scan whole slides, large storage size for WSI, bandwidth restrictions, undefined legal implications, professional reluctance, and lack of standardization in the imaging process.

Diagnostic difficulties and pitfalls in rapid on-site evaluation of endobronchial ultrasound guided fine needle aspiration.

Background: One of the novel techniques utilizing fine needle aspiration (FNA) in the diagnosis of mediastinal and lung lesions is the endobronchial ultrasound (EBUS)-guided FNA. In this study, we describe five cases which had a discrepancy between on-site evaluation and final diagnosis, or a diagnostic dilemma when rendering the preliminary diagnosis, in order to illustrate some of the diagnostic difficulties and pitfalls that can occur in EBUS FNA. Methods: A total of five EBUS FNA cases from five patients were identified in our records with a discrepancy between the rapid on-site evaluation (ROSE) and final diagnosis, or that addressed a diagnostic dilemma. All of the cases had histological confirmation or follow-up. The cytomorphology in the direct smears, cell block, and immunohistochemical stains were reviewed, along with the clinical history and other available information. Results: Two cases were identified with a nondefinitive diagnosis at ROSE that were later diagnosed as malignant (metastatic signet-ring cell adenocarcinoma and metastatic renal cell carcinoma (RCC)) on the final cytological diagnosis. Three additional cases were identified with a ROSE and final diagnosis of malignant (large cell neuroendocrine carcinoma (LCNEC) and two squamous cell carcinomas), but raised important diagnostic dilemmas. These cases highlight the importance of recognizing discohesive malignant cells and bland neoplasms on EBUS FNA, which may lead to a negative or a nondefinitive preliminary diagnosis. Neuroendocrine tumors can also be difficult due to the wide range of entities in the differential diagnosis, including benign lymphocytes, lymphomas, small and nonsmall cell carcinomas, and the lack of immunohistochemical stains at the time of ROSE. Finally, the background material in EBUS FNAs may be misleading and unrelated to the cells of interest. Conclusions: This study illustrates the cytomorphology of five EBUS FNA cases that address some of the diagnostic challenges witnessed while examining these specimens during ROSE. Many of the difficulties faced can be attributed to the baseline cellularity of the aspirates, the bronchial contamination, the difficulty identifying neoplasms with bland cytology, the wide spectrum of diseases that can occur in the mediastinum with overlapping cytomorphologic features, the mismatch between the background material and the cell populations present, and the overall unfamiliarity with these types of specimens.

Diagnostic accuracy and limitations of fine-needle aspiration cytology of bone and soft tissue lesions: a review of 1114 cases with cytological-histological correlation.

Fine‐needle aspiration (FNA) cytology is increasingly being used as a diagnostic modality for soft tissue and bone lesions. These diagnoses can be challenging because of a variety of factors, including interpretation and sampling issues. This study investigates the diagnostic utility of FNA biopsy, in addition to the diagnostic pitfalls, in soft tissue and bone cytopathology.

Evaluation of endobronchial ultrasound‐guided fine‐needle aspirations (EBUS‐FNA): Correlation with adequacy and histologic follow‐up

Endobronchial ultrasound‐guided fine‐needle aspiration (EBUS‐FNA) is a minimally invasive modality for diagnosing mediastinal lesions. When determining adequacy, EBUS‐FNAs are evaluated for diagnostic material or sufficient lymphoid tissue. In this study, the authors evaluated their experience with EBUS‐FNAs and correlated the findings with adequacy and histologic follow‐up.

Endoscopic ultrasound-guided fine-needle aspiration of metastases to the pancreas: A study of 25 cases

Background: Metastases to the pancreas are an uncommon cause of pancreatic masses seen on endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA). The purpose of this study is to retrospectively review the cytomorphology, clinical findings, and results of ancillary studies in a large series of these unusual cases. Materials and Methods: We searched our institutions pathology database for EUS-guided FNAs of the pancreas that were diagnostic of metastatic tumor over a 5-year period. The final cytologic diagnosis, results of ancillary studies, corresponding histological material, and clinical follow-up data were reviewed in these cases. Results: A total of 1172 pancreatic EUS-guided FNAs were identified, of which 25 cases (2.1%) had a confirmed diagnosis of a pancreatic metastasis. This included 12 (48%) cases of renal cell carcinoma, 3 (12%) melanomas, 3 (12%) small cell carcinomas, and 7 (28%) other malignancies. In these metastatic tumors involving the pancreas, 20 (80%) of the lesions were solitary. Four (16%) cases had no prior history of malignancy. The average time to diagnosis of pancreatic metastasis was 5.3 years. Immunohistochemistry and special stains were performed in 22 (88%) and 9 (36%) cases, respectively. Conclusions: Our data shows that although metastases to the pancreas are rare, they can present as a solitary mass many years after the primary malignancy is diagnosed and can even be the first manifestation of an extrapancreatic primary in a small number of cases. It is important to consider the possibility of a metastatic lesion in the pancreas because this may require a different management than a primary pancreatic tumor.

Benign non-infectious causes of lymphadenopathy: A review of cytomorphology and differential diagnosis

Fine‐needle aspiration (FNA) biopsy is a quick, cost‐effective, and safe diagnostic modality that provides answers to guide treatment and management in patients with lymphadenopathy. In adults and children, there are a range of non‐neoplastic, non‐infectious etiologies for lymphadenopathy. These include reactive lymphoid hyperplasia (RLH), dermatopathic lymphadenitis (DLN), Rosai‐Dorfman disease, Castleman disease, Kimura disease, Kikuchi‐Fujimoto disease, and lymphadenopathy associated with autoimmune and metabolic/storage disease. Other benign nodal entities that may be encountered include lymph node infarction, foreign body reactions, drug reactions, extramedullary hematopoeisis, and benign inclusions. This article reviews the practical role of FNA in the evaluation of these benign, non‐infectious causes of lymphadenopathy and focuses on their cytomorphology and differential diagnosis. Diagn. Cytopathol. 2012;

Correlation of Cytomorphology and Molecular Findings in EGFR+, KRAS+, and ALK+ Lung Carcinomas

OBJECTIVES There is increasing emphasis on the subclassification of non-small cell lung carcinomas (NSCLCs) and molecular features to guide treatment. Histologic studies have suggested some morphologic features predominating in tumors. Our aim was to determine if mutated cases had distinct cytomorphology. METHODS A retrospective study was designed to retrieve all cytopathology cases of NSCLC that had mutation studies for EGFR or KRAS or fluorescence in situ hybridization studies for ALK between 2007 and 2012. All slides from available mutation-positive cases were reviewed, and cytomorphologic features were correlated to mutation status. RESULTS Of the cases with molecular testing, 62 (39%) of 160 were positive for mutation, including 39 (31%) positive for KRAS, 20 (14%) for EGFR, and 4 (3%) for ALK (one case positive for both EGFR and ALK). More of ALK+ and KRAS+ cases had a diagnosis of NSCLC-favor adenocarcinoma or NSCLC not otherwise specified than did EGFR+ cases (25; 51% vs 5%). Eosinophilic granular cytoplasm was seen in more ALK and KRAS cases than in EGFR cases (100; 32% vs 6%). CONCLUSIONS Cytologic features of ALK+ and KRAS+ tumors included more nuclear pleomorphism, necrosis, and a less vacuolated cytoplasm than did EGFR+ tumors, which may explain the less definitive subclassification in ALK+ and KRAS+ tumors.