Role of cytoblock on pleural effusion for diagnosis of malignant disease

BACKGROUND

Thoracocentesis of pleural effusion is a simple technique for pleural fluid examination through cytology. In addition to cytological examination to assess the nature of pleural fluid content, we can also perform more detailed examinations through cytoblocks of residual fluid. These paraffin-embedded cytoblock samples are important because we can perform examinations as in other bioptic samples. In these samples, immunohistochemical and molecular analyses can be performed.

METHODS

Two hundred fifty-five cytological samples from patients with pleural effusion were examined. In cases in which the presence of malignant cells was identified in the cytological examination, as well as cases that were suspicious but not definitive for the presence of a malignant effusion, a cytoblock was prepared. Histological examination and immunohistochemical analysis were performed.

RESULTS

Among 255 cases with pleural effusion, 152 had the presence of malignant cells and 6 cases were suspicious, but uncertain for the presence of malignant cells, while 86 cases had inflammatory pleural effusion or other pathologies but were not malignant. After histological analysis of the cytoblock and immunohistochemical analysis, we identified 82 malignant tumors of the lung, 8 malignant tumors of the gastrointestinal tract, 15 malignant tumors of the breast, and 6 malignant tumors of the female genital tract, as well as 24 tumors of undetermined origin.

CONCLUSIONS

Cytoblocks are important for the diagnosis of the primary nature of malignant pleural effusions. The highest importance is primary lung tumors, as well as those tumors in which the primary site of the tumor cannot be determined clinically.

Automated Cellient(™) cytoblocks: better, stronger, faster?

OBJECTIVE

Cytoblocks (CBs), or cell blocks, provide additional morphological detail and a platform for immunocytochemistry (ICC) in cytopathology. The Cellient(™) system produces CBs in 45 minutes using methanol fixation, compared with traditional CBs, which require overnight formalin fixation. This study compares Cellient and traditional CB methods in terms of cellularity, morphology and immunoreactivity, evaluates the potential to add formalin fixation to the Cellient method for ICC studies and determines the optimal sectioning depth for maximal cellularity in Cellient CBs.

METHODS

One hundred and sixty CBs were prepared from 40 cytology samples (32 malignant, eight benign) using four processing methods: (A) traditional; (B) Cellient (methanol fixation); (C) Cellient using additional formalin fixation for 30 minutes; (D) Cellient using additional formalin fixation for 60 minutes. Haematoxylin and eosin-stained sections were assessed for cellularity and morphology. ICC was assessed on 14 cases with a panel of antibodies. Three additional Cellient samples were serially sectioned to determine the optimal sectioning depth. Scoring was performed by two independent, blinded reviewers.

RESULTS

For malignant cases, morphology was superior with Cellient relative to traditional CBs (P < 0.001). Cellularity was comparable across all methods. ICC was excellent in all groups and the addition of formalin at any stage during the Cellient process did not influence the staining quality. Serial sectioning through Cellient CBs showed optimum cellularity at 30-40 μm with at least 27 sections obtainable.

CONCLUSIONS

Cellient CBs provide superior morphology to traditional CBs and, if required, formalin fixation may be added to the Cellient process for ICC. Optimal Cellient CB cellularity is achieved at 30-40 μm, which will impact on the handling of cases in daily practice.