Background:Patients with pleural fluid obtained from thoracocentesis, should be submitted for biochemical, microbiological, and cytological study, especially in those cases suspicious  of malignant pleural effusion (MPE).

The aim of this study was to emphasise the cost effectiveness of applying cell block in malignant pleural effusion patients,decreasing need for more invasive and costilier diagnostic methods like thoracospocy and image guided pleural biopsies.

Methods:This was a  5 years retrospective study (2018-2022) conducted to the patients hospitalized in our hospital with pleural effusions.Malignant Pleural fluid was collected and  cytology smear and cell block were made from the fluid.Immunohistochemical stains were applied.

Results:From 4098 patients with pleural effusion,14%(n-581) were malignant.

In MPE  patients,56% were male and 44% females.The most common primary site involved in MPE was lung (51%),followed by breast cancer (34%),ovary (7%),melanoma (5%).

For the remaining we were not able to find histiogenesis, because of the insufficient material.

In patients with lung cancer,EGFR resulted positive in 8 patients,5 patients ALK + and only 2 patients PDL-1 positive(not all patients did,because of the costs).

Conclusions:Cytology smear combined with cell block increases the diagnostic yield  in MPE.

Cell block is a simple,unexpensive  method and do not require any special trainning or instrument.

It  shoud be considered as a useful adjuvant thechnique  not only for the histiogenesis, but also for the evaluation of predictive histopathological factors and molecular tests, avoiding invasive bioptic procedure, especially in developing countries like Albania.