Computed Tomogram Guided Fine-Needle Aspiration Cytology of Lung and Mediastinal Masses: A Study of 166 Cases

Computed Tomogram Guided Fine-Needle Aspiration Cytology of Lung and Mediastinal Masses: A Study of 166 Cases

*Alam MA,1 Islam MR,2 Haque MR, Nath SK4

 Abstract
Computed tomogram guided fine needle aspiration cytology (FNAC) is an important and useful investigation to differentiate between benign and malignant lesions of lung and mediastinum. To evaluate the lung and mediastinal masses and to analyze and compare the results with cytological findings, 166 patients were retrospectively studied who underwent CT guided FNAC over a period of January 2015 to December 2016. The study was carried out in patients who presented with respiratory symptoms with a localized lung and mediastinal masses which were confirmed by radiologically was sent for FNAC. 155 cases of lung masses and 11 cases of mediastinal mass were included in this study. Patients’ age ranged from 15 to 95 year and the male to female ratio was 4:1. Radiologically, out of 166 cases, 140 cases were diagnosed as malignant, 8 cases as benign and 18 cases as inflammatory lesions. Cytologically, 146 cases were diagnosed as malignant, 20 cases were benign inflammatory lesion. Most common lung malignancy was squamous cell carcinoma (72 cases) followed by adenocarcinoma (32 cases), small cell carcinoma (10 cases), large cell carcinoma (8 cases), 18 cases of lung metastasis were seen. Compared to biopsy, CT guided FNAC shortens the diagnostic interval and helps in differentiating lung malignancy into different cytopathological types which aids in proper management of the malignant lesion. Out of 11 mediastinal masses 6 cases were malignant lymphoma, 3 cases specific inflammatory lesions (tuberculosis) and 2 cases was non-specific inflammatory lesions.

[Journal of Histopathology and Cytopathology, 2018 Jan; 2 (1):19-22]

Keywords: Computed tomogram, Cytology, Guided FNAC, Lung mass, Mediastinal mass.

 

  1. *Dr. Md. Ashraful Alam, Associate Professor, Department of Pathology, Rangpur Medical College. drashraful09@gmail.com
  2. Md. Rezaul Islam, Senior Consultant, Radiology & Imazing, Sadar Hospital, Nilphamari.
  3. Md. Rashedul Haque, Associate Professor, Department of Biochemistry, Rangpur Medical College.
  4. Professor Swapan Kumar Nath, Department of Radiotherapy, Rangpur Medical College.

 

* For correspondence

 Introduction

A Computed tomography (CT) guided fine needle aspiration cytology (FNAC) is a well known modality for characterization of mediastinal masses. CT guided FNAC of lung lesions is a well established technique for the cytologic diagnosis of peripheral malignant lung lesions, with a reported diagnostic accuracy rate more than 93% and a sensitivity rate less than 95%.1,2 It has been used to differentiate mediastinal masses into benign, malignant and inflammatory types. Furthermore, its use has been extended in differentiating lung malignancy into different cytopathological types which aids in proper management of the malignant lesions. CT guided FNAC is widely recognized technique in indeterminate mass. It is a simple diagnostic method of relatively low cost, with negligible mortality and limited morbidity.3 The accuracy of CT guided FNAC for discriminating benign from malignant lesion has been recorded to vary from 64% to 97%.4 Several post procedural complications have been reported for CT guided FNAC such as pulmonary hemoptysis and pneumothorax. The risk for developing pneumothorax has been observed to be 22% – 45% due to high sensitivity of CT in detecting pneumothorax.5 Relative contraindications to image guided FNAC are severe chronic obstructive airway disease, bleeding diathesis, contra lateral pneumonectomy and pulmonary arterial hypertension.6 The purpose of our study is to evaluate the accuracy of CT and CT guided FNAC in differentiating and recording the pathological spectrum of the mediastinal and lung masses.

 Methods

This is a retrospective study conducted in a private medical college hospital at Rangpur and two private laboratories in Rangpur city from Janary 2015 to December 2016.The study was carried out in 166 patients who presented with lung and mediastinal mass attended to different physicians and Rangpur Medical College Hospital and were sent for Fine needle aspiration cytology. Relevant clinical history and investigations were obtained from the patient to narrow down the differential diagnosis and to decide if patient was eligible for FNAC, such as history of bleeding diathesis, thrombocytopenia, dyspnea, uncontrolled cough, other feature of chronic obstructive airway diseases (COPD), pulmonary arterial hypertension etc. CT guided FNAC was performed in patients with peripheral lung and mediastinal mass or masses which were only approachable by spinal needle. Patient inclusion criteria included: cooperative patient who was able to hold breath for a short while, no bleeding tendency, patient who was to undergo chemo or radio-therapy and lesions not approachable by USG. Informed and written consent was taken from the patient explaining the risk and benefits of the procedure. Axial section of the area of interest was taken after a scanogram. A feasible approach was judged and the patient positioned accordingly with radiopaque marker placed at the site of puncture. Then under all aseptic precaution aspiration done by 21-22 G spinal needle and 10 cc disposable syringe and smear was prepared in glass slide for fixation in 95% alcohol. Routine Papaniculau stain were done in all cases.

 Results

The data were collected from January 2015 to December 2016. Our study included 166 patients, out of which 155 with lung and 11 with mediastinal mass were subjected to CT guided FNAC. Their ages ranged from 15 to 95 years with mean age of 65 years (Table I). The male to female ratio was 4:1. Out of 155 lung  malignant cases squamous cell carcinoma (Fig 1, 72 cases) was the commonest followed by adenocarcinoma ( fig 2, 32 cases), 10 cases of small cell carcinoma, 8 cases of large cell carcinoma were seen. Out of 18 cases of metastatic tumors, 10 cases were from gastrointestinal tract, 2 cases from testis and 6 cases from thyroid follicular carcinoma (Table IV). Out of 15 inflammatory cases 7 cases was specific inflammatory (tuberculosis) 8 cases was non- specific inflammatory lesion was observed. (Table IV). Out of 11 mediastinal masses 6 cases were malignant lymphoma,3 cases ware specific inflammatory lesions(tuberculosis) and 2 cases were non-specific inflammation was observed (Table V).

Table I: Age distribution (n=166)

Age Groups
(Years)
Male Feamle Total %
15-25 6 3 9 5.42%
26-35 5 3 8 4.81%
36-45 13 4 17 10.42%
46-55 24 13 37 22.28%
56-65 30 12 42 25.30%
66-75 34 3 37 22.28%
>75 15 1 16 9.6%

 

Table II: Sites of the lesions (n=166)

Sites No %
Pulmonary 155 93.37
Mediastinal 11 6.62

Table III: Lung lesions by site and sex

 

Sex Site
Right Lung Left lung Total
Male 102(76.69%) 31(18.67%) 133(80.12%)
Female 20(60.60% 13(39.39%) 33(19.87%)
Total 122(73.49%) 44(26.50%) 166

 

Table IV: CT guided FNAC diagnosis of intrathoracic and mediastinal masses (n=166)

 

Cytological Findings: No(%)
Squamous cell carcinoma 72(43%)
Adenocarcinoma 32(19.27%)
Small cell carcinoma 10(6.02%)
Large cell carcinoma 8(4.81%)
Metastatic carcinoma 18(10.84%
Malignant Lymhoma 6(3.61%)
Specific Inflammatory lesions(TB) 10(6.02%)
Non specific inflammatory lesion 10(6.02%)

 

Table V: CT guided FNAC diagnosis of mediastinal masses (n=11)

 

Cytological Findings: No (%)
Malignant lymphoma 6(54.54%)
Specific Inflammatory lesion(TB) 3 (27.27%)
Non-specific inflammatory lesion 2(18.18%)

TB=Tuberculosis

 

 

 

 

 

 

Figure 1. Photomicrograph of sqamous cell carcinoma of lung (Cytopathology)

 

 

 

 

 

Figure 2. Photomicrograph of adeno carcinoma of lung (Cytopathology)

 Discussion

CT guided transthoracic FNAC is a safe and accurate means of diagnosing benign and malignant intrathoracic lesions. In this study, Out of 166 patients 5.42% were in the age group from 15-25 years and 25.30%were in the age group of 56-65 years which is not similar with the study of Sarker RN et. al 7 who found patients of intra-thoracic mass 36% in the age group ranging from 46-55 years and 21% in the age group of 56-65 years, these two groups were predominant in terms of age. There were 133  male (80.12%) and 33 female (19.67%). In the study of Sarker RN et. al7 out of 100 cases there were 77 men (77%) and 23 (23%) were women. This correlates with the well-known fact that intrathoracic mass occurs most commonly in older age group and in males than in females. Female cases are less because malignant pulmonary lesions are less in females in our population. Male: Female ratio was 4:1 in our study. That is similar to the study done by Ahmed et al.8 The locations of the pulmonary lesions were in right lung 122 (73.49%), and 44 (26.50%) in left lung. In the study of Ahamad et al8 lesion in right lung was 98 (60.49%), in left lung 64 (39.41). In the final diagnosis, squamous cell carcinoma was the commonest malignant tumour followed by adenocarcinoma and metastatatic carcinoma. These findings are similar to the findings of the study done by Mostafa et al9 although his study was not guided by CT and the number of cases was less. Our experience is similar to the study of Singh et al10 where fatal complications like tension pnemothorax, air embolism, endo bronchial haemmorhage etc were absent. The complication rate depends on the distance of the lesion from pleura and lesion size. The more the amount of the lung tissue traversed by the needle the more was the complication rate and smaller the lesion the more was the complication rate. In this study fine needle of 21- 22G was used where the chance of complication seems to be minimum which correlates well with the study of Zavala et al.11  Saha A et al12 in their series have reported cases of mediastinal masses, 3 (5.6%) cases was NHL and (1cases) was Hodgkin’s lymphoma.In our study 6 cases (54.54%) was malignant lymphoma. This discrimination may be due to total number of cases.

Conclusion

This study concludes that CT guided lung and mediastinium needle aspiration cytology by spinal needle is a highly effective procedure in the diagnosis and sub- classification of mass lesions. It is a relatively simple, cost effective procedure with good patient compliance and low morbidity. The use of CT-guided FNAC of intrathoracic mass lesions reduces the diagnostic interval and cost. It also avoids unnecessary thoracotomy for diagnostic purposes. As the facilities continue to improve; it is likely to have a greater role in the initial evaluation of intrathoracic and mediastinal mass in the near future.

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