Utility of cell block to detect malignancy in fluid cytology: Adjunct or necessity?

Cell block (CB) technique when supplemented with conventional smear, provides increased cellularity, preservation of architectural pattern with excellent morphology, and a clear background. We compare the utility of CB technique compared to conventional smear in detection of malignancy in serous effusions.

An institution-based observational and analytical study was carried out over 1 year on 50 patients with effusions. The residual amount of centrifuged deposit after preparation of conventional smear was mixed with 10% alcohol-formalin solution, and CBs were prepared. Calretinin and cytokeratin 5 were used for reactive mesothelial cells and Wilms tumor 1, thyroid transcription factor 1, CDX2, and estrogen receptor were used to confirm the adenocarcinoma cells.

Maximum patients belonged to the age group of 61-70 years. Male:female ratio 1:1.17. Most common cause of malignant peritoneal effusion was due to ovarian malignancies in females and adenocarcinoma of stomach in males while, in case of pleural effusion, it was breast carcinoma in females and lung carcinoma in males. Thirteen suspicious cases were subjected to immunohistochemistry (IHC). In 70% cases, CB findings were consistent with the findings of conventional smears. In 20% cases, the conventional smears were suspicious for malignancy, and malignancy was confirmed by CB technique, whereas in 10% cases, both smears and CB were suspicious for malignancy and the original nature of the lesion was confirmed by the IHC. Sensitivity and specificity of CB compared to conventional smear were 88.88% and 86.98%, respectively.

CB produced significantly better results (P = 0.0271) while detecting malignant lesions and reducing suspicious results (P = 0.0226).