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

Abstract

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.

Punção aspirativa guiada por ultrassom endobrônquico no diagnóstico e estadiamento de linfadenopatia mediastinal: experiência inicial no Brasil

“…The international literature refers to this working structure as rapid on site cytology. (11) Although the advantages of this scheme are indisputable because it facilitates rapid clinical decision-making, few centers can afford to maintain an in-room pathologist who has time to wait for the test. This scheme is justifiable in a scenario where cases with nondiagnostic EBUS results are further investigated via mediastinoscopy or video-assisted thoracoscopy.…”

Ultrasonido endobronquial más aspiración con aguja fina y evaluación patológica rápida en sala. Medicina de precisión y trabajo multidisciplinario: serie de casos

“…Estos resultados son comparables con los publicados en la literatura mundial; por ejemplo Gilbert y colaboradores (8) publicaron un 68,1% de diagnóstico en sala e incrementaron su rendimiento al 79,7% en el bloque celular; vale anotar que la calidad de la muestra y la pericia del neumólogo intervencionista influyen en los porcentajes de diagnóstico. En cuanto al diagnós-tico de lesiones neoplásicas malignas (carcinoma de células no pequeñas-CPCNP), se observó una rentabilidad diagnóstica del 91% y una exactitud diagnós-tica del 97%, datos semejantes a los publicados en la literatura, que en CPCNP corresponde a una rentabilidad diagnóstica del 86,6% y exactitud diagnóstica del 94,8% (8)(9)(10). También conviene aclarar que es importante el entrenamiento del patólogo en patología pulmonar y específicamente en citopatología pulmonar para EBUS, donde las condiciones morfológicas celulares varían al utilizar la coloración de Diff-Quick y se presentan dificultades en la determinación de cé-lulas linfoides aplastadas vs. células neoplásicas de carcinomas de células pequeñas y células malignas sueltas.…”

Diagnostic utility of arborizing stromal meshwork fragments in mucinous tumors

“…Although we have been performing fine‐needle aspiration (FNA) for decades, identifying true mucinous neoplasms remains a challenge in cytology specimens given the paucity of neoplastic cells in some cases. This is particularly difficult today given that the use of endoscopic ultrasound (EUS)‐guided procedures has increased in the past decade with the emergence of EUS‐guided transbronchial needle aspiration (EBUS‐TBNA), and these specimens frequently have mucoid contamination . Thus, it is important to be able to morphologically distinguish true mucin from contamination and mimickers.…”