Cyto-histopathological study of Mediastinal lesions

Background: Broad ranges of non-neoplastic and neoplastic lesions are encountered in mediastinum depending on the patient’s age and anatomical site. This study was performed to review our institutional experience of mediastinal masses and to compare the results with various other studies. Materials and Methods: This was a retrospective study conducted on 112 patients with mediastinal masses who underwent fine needle aspiration cytology and/or biopsy from 14 th April 2009 to 4 th March 2014 in Department of Pathology, Institute of Medicine, Tribhuvan University Teaching Hospital. Results: Out of 112 cases, 70 cases (62.5%) were benign, 38 cases (33.92%) malignant and 4 cases (3.57%) were inconclusive. Mean age of presentation was 34.94 yrs with male to female ratio of 1.2:1. Ninety-nine cases (88.4%) were seen in anterior compartment, 12 cases (10.7%) in posterior compartment and 1case (0.9%) in middle compartment. Thymoma (26 cases) was the most common lesion followed by Non Hodgkin lymphoma (17 cases) and germ cell tumor (16 cases). Conclusion: Mediastinal lesions occur more commonly in males with higher frequency of benign lesions, among which thymoma is the predominant lesion.


INTRODUCTION
The mediastinum can be deined as those tissue and organs that occupy thoracic cavity between pleural cavities and lung laterally, between sternum anteriorly and vertebral column posteriorly and from thoracic inlet down to diaphragm. 1 It is usually divided into anterior, middle and posterior compartments to help categorize tumors and disease according to their site of origin and location. 2attarai N 1 1 Department of Pathology, Grande International Hospital Pvt.Ltd, Kathmandu, Nepal Speciic tumor types show proclivities to occur in speciic compartments. 1The relative frequency of various lesions are considerably different in these compartments and also in different age groups. 3ny mediastinal masses are serendipitously discovered on chest radiograph obtained for other reasons.Some patients will come to clinical attention with vague chest complaints or with sign and symptoms related to compression or invasion of mediastinal structure. 2FNA is a good diagnostic tool in lesions of mediastinum as a irst attempt to tissue diagnosis. 4Cutting needle techniques are used when FNA diagnosis is uncertain. 5This study was done to review and analyze all the cases of mediastinal lesions of the last 5 years period.

MATERIALS AND METHODS
This is a retrospective descriptive study performed on 112 patients with mediastinal lesion who underwent FNAC and/or tissue biopsy over 5 years period from 14 th April 2009 to 4th March 2014 in Department of Pathology, Institute of Medicine, Tribhuvan University Teaching Hospital.Permission was obtained from institutional review committee.FNAC was done using 23 gauge needle attached to 10 ml syringe.Cytological material was smeared on clean glass slide.The smear was immediately immersed in 95% alcohol for papanicolaou stain and air-dried for Giemsa stain.The surgical specimen were formalin ixed, routinely processed and stained with Hematoxylin and Eosin stain.The slides were reviewed by pathologist and diagnosis was made.Computer database in the department was used to extract all the information pertinent to the was performed using info

DISCUSSION
The types of mediastinal mass examined in this study broadly relect range of pathological conditions seen in our clinical practice.Biopsy of mediastinal mass can be performed by variety of techniques ranging from FNAC to surgical procedures allowing resection or biopsy. 6A major advantage of FNAC is that immediate cyotological examination of specimen is possible. 5 Demographics in this study is similar to those in previous reported series with wide range of age (4 months-77 years) and mean age of 34.94 yrs.In a study of Shabb N.S. et.al age range was 10-72 yrs and similar to their study our study also showed male predominance. 4xty one and half % cases in our study were benign followed by 33.9% malignant.This was in contrast to study by Zafar N. et.al 7 who detected higher rate of malignancy about 74% but show concordance with study done by Strollo   This study showed most common lesion of mediastinum was thymoma followed by NHL and Germ cell tumor.This was in contrast to study by Temes R et.al who showed lymphoma as commonest lesion. 11,12NHL were common in 2 nd -3 rd decade and germ cell in 2 nd -4 th decade of life which is in accordance with other studies. 13The sensitivity of FNAC in diagnosing is 72.7% in this study.This is that by Shabb et.al in his study which was about 83%. 13       malignancy is 100%.This shows FNAC is fairly accurate in diagnosing malignant lesion in Mediastinum. 5

CONCLUSION
Mediastinal lesion are more common in male and in anterior mediastinum with higher frequency of benign lesion most of them being Thymoma.FNAC is a good diagnostic tool in lesion of mediastinum as a irst attempt to tissue diagnosis.

D
.C. et.al 2 who demonstrated two third of all mediastinal masses as benign.Majority of lesions were seen in anterior mediastinum .In a study by Sterret G et.al also majority of lesions were seen in anterior mediastinum. 8Previous studies by Mohan N. et.al 9 and Vaziri M. et.al 10 mediastinal lesions were more common in third decade of life which is true in our case too.
to the study done by Morrissey B. et.al of FNAC in diagnosing Bhattarai N et al.