Unique Ultrastructural Features in Diagnosis of Hepatocellular Carcinoma in Fine Needle Aspiration Cytology Specimen.
Anmaar Abdul-Nabi, Gurdip Sidhu, Nicholas Cassai, Jie Liao, Guang-Yu Yang. Northwestern University, Chicago, IL; NYU School of Medicine, NewYork, NY
Background: Fine needle aspiration cytology (FNAC) has been widely used as a minimally invasive and rapid method of diagnosis of primary or metastatic hepatic masses. But its sensitivity appears low (67% to 93%) and a negative result does not exclude malignancy. Although immunohistochemistry is commonly used as an ancillary test, definitive biomarker for hepatocellular carcinoma (HCC) is lacking. Many studies have shown that electron microscopy (EM) has the precise ability in identifying normal and neoplastic hepatocyte ultrastructurally, but its use is still limited. Our study aims to characterize unique ultrastructural features of HCC and evaluate its usefulness as a diagnostic tool in FNAC.
Design: FNAC specimens from 67 cases of HCC with different degrees of differentiation confirmed histopathologically by core-needle biopsy or hepatoectomy were collected between 1993-2003. Parallel FNAC specimens were submitted for EM examination.
Results: Among 67 HCC cases, 95% (64/67) of the cases was confirmed the FNAC diagnosis of HCC. In 3 discrepancy cases, EM established a definitive diagnosis of metastatic colonic adenocarcinoma, and the two other cases EM diagnostic accuracy was limited by failure to obtain adequate sample. The following unique ultrastructural features in diagnosing 64 HCC cases were identified as: 1) Capillarization which were trabecular neoplastic hepatocytes surrounded by fenestrated or not separated endothelia with continuous basal lamina (Fig.1A); 2)altered bile canaliculi which commonly formed by more than three neoplastic hepatocytes and usually contained bile material (Fig.1B)
; 3) high atypical round to irregular shape nuclei with very large, ropy nucleoli that had nucleolonema (Fig.1C). Intranuclear cytoplasmic inclusions and giant mitochondria were also observed in the neoplastic cells.
Conclusions: Our results indicate that HCC displays unique ultrastructural features, which can be used as a reliable and accurate diagnostic tool for HCC in limited FNAC. EM is superior to FNAC in determining the tumor origin and in making more definitive diagnosis.
Wednesday, March 2, 2011 9:30 AM
Poster Session V # 280, Wednesday Morning