Introduction
Lymph node enlargement can be secondary to various diseases comprising of inflammatory, neoplastic and other causes. Fine needle aspiration cytology (FNAC) is efficient in diagnosing the etiology of enlarged lymph nodes in most of the circumstances.1 Lymphnodes are the commonest site of involvement in various malignancies. FNAC is cost effective, easily performed and reliable diagnostic modality for all the palpable swellings including lymphnode enlargement.2 In case if deeper lymphnodes are involved, FNAC can be performed efficiently under guidance, especially ultrasonography (USG) - guided.
In the USA, in 1921 Gulhrie described a method of using aspirated material to diagnose various disease causing cervical lymph node enlargement, which was reported to be the earliest use of FNA. FNAC has a significant role in neck lymph nodes, particularly those with metastasis.3 FNAC confirms the presence of metastatic disease and gives a clue regarding its nature and origin of primary malignancy. It is very useful in detecting recurrence and new metastases. Hence, it is an important and reliable tool in follow-up of malignant conditions. However, histopathological examination will always be considered as the gold standard in diagnosing varied lymphadenoapathy etiologies, especially in lymphomas but in many metastatic malignancy FNAC may be the only tool for diagnosis and further management of the patients.4 Diagnostic dilemma is not uncommon, especially in cases where the metastatic lymphnodes have turned cystic, example metastatic squamous cell carcinoma or papillary thyroid carcinoma deposits. In such cases, FNA from multiple sites and meticulous examination of smears for detecting malignant features is essential.
The present study was undertaken to learn about the series of metastatic lymphnode deposits and evaluate common age group, gender and site involved.
Materials and Methods
A cross-sectional descriptive study was conducted from January 2008 – May 2012. Fine needle aspiration cytology (FNAC) of lymph nodes with metastatic deposits performed in Pathology department, SDM College of Medical Sciences and Hospital, Dharwad were included in the study after seeking permission from the Departmental Head. For retrospective data; pertaining to age, gender, site and clinical history, all was obtained from FNAC request forms. For prospective data, thorough clinical history and examination was performed. After explaining the procedure to the patient, under aseptic precaution FNAC was performed using 22 – 23 G needle and 10ml disposable syringe. Aspirate was smeared on the slides and dried smear was stained with Leishman stain, whereas 95% alcohol fixed smears were stained with Papanicolaou stain and Hematoxylin & Eosin stain. Wherever indicated, on a dried smear Ziehl-Neelson stain for Acid Fast Bacilli was performed.
Slides were collected from departmental archives and reviewed. Clinical data was analysed and descriptive statistics was used in the study.
Institutional ethical clearance has been obtained.
Results
Total of 4095 FNAC was performed during the study period, with lymph node FNAC accounting for 828 cases. Metastatic lymphnode deposit FNAC included in the study were 148. Commonest metastatic deposit was Squamous cell carcinoma deposits (60.81%), followed by Adenocarcinoma deposit (19.59%). Other conditions – 6.75% Positive for malignancy without being further typed; 3.37% Malignant melanoma deposits (Figure 2); 2.70% Papillary carcinoma Thyroid deposits (Figure 5); 1.35% each of deposits from Large cell Neuroendocrine carcinoma (Figure 3), Small cell carcinoma, Nasopharyngeal carcinoma; 0.67% each of deposits from Non-small cell carcinoma, Germ cell tumor, Carcinosarcoma or Sarcomatoid/ Spindle cell carcinoma (Figure 4) and Small round cell tumor (Table 1).
Table 1
Distribution pattern of various Lymphnode metastatic deposits
Range of age at presentation was 22 – 86yrs with commonest age group (Table 2) affected being 51 – 60 yrs (41.89%). Male: Female ratio was 3.77:1. Commonest site involved (Figure 1) was Cervical lymphnode (74.32%), followed by Supraclavicular lymphnode (8.78%), Axillary lymphnode (8.78%) and Inguinal lymphnode (8.10%).
Table 2
| Age group | No. of cases | % of cases |
| 21 – 30yrs | 06 | 4.05 |
| 31 – 40yrs | 12 | 8.10 |
| 41 – 50yrs | 35 | 23.64 |
| 51 – 60yrs | 62 | 41.89 |
| 61 – 70yrs | 18 | 12.16 |
| 71 – 80yrs | 13 | 8.78 |
| 81 – 90yrs | 02 | 1.35 |
| Total No. of cases | 148 |
Age group involved in Lymphnode metastatic deposits
Primary site of malignancy was suspected in 31 cases: 9 in Upper Aerodigestive tract, 8 in Breast, 4 in Thyroid, 3 in Lung, 2 in Nasopharyngeal, 2 in Gastrointestinal tract, 1 in Bladder, 1 in Prostate and 1 in Pancreas. Follow-up was available in 17 cases and majority (12) were cytologically diagnosed as Metastatic Squamous cell carcinoma deposits and on histopathology all these cases showed Primary Squamous cell carcinoma in the following sites – supraglottic area, pyriform fossa, vallecula, tongue, tonsil, cervix and larynx. 01 case with axillary ductal carcinoma deposits showed Primary Invasive ductal carcinoma breast with axillary lymphnode metastasis on histopathology. 01 case on cytology was diagnosed as Metastatic adenocarcinoma deposits and on histopathology Primary was detected in Esophagus having Poorly differentiated Squamous cell carcinoma. 02/03 cases of Positive for Malignancy on cytology were diagnosed as Primary Moderately differentiated Squamous cell carcinoma and 01 case was diagnosed as Primary Nasopharyngeal carcinoma on histopathology.
Figure 1
Malignant melanoma deposits. Leishmann stain (10 X) – discohesive pleomorphic plasmacytoid cells, binucleate cells, intracellular and extracellular melanin pigment.
Figure 2
Large cell neuroendocrine carcinoma deposits. H & E stain (10X) – large pleomorphic cells with stippled nuclear chromatin and inconspicuous nucleoli
Discussion
Malignancies in lymph nodes mostly are metastatic in nature with an incidence ranging from 65.7% to 80.4% and for lymphomas the incidence ranges from 2% to 15.3%, among lymph nodes aspirated from all different sites.7, 6, 5 So, lymph node aspiration plays a key role in the diagnosis of malignant lymphadenopathies.
In present study, common age group involved was 51 -60yrs with 41.89% of cases. Similar, finding was observed in studies done by Rai N N et al,2 Prasad S et al3 and Nama S et al4 showing 41-60yrs, 5th – 6th decade and 51 – 60yrs age group being commonly involved with 54.2%, 58%, 47.93% of cases respectively. They also showed male predominance with Male:Female ratio of 3.75:1, 3:1 and 2.78:1 in their respective studies. Male:Female ratio in the present study was 3.77:1. In the present study, cervical lymphnode was commonly involved followed by supraclavicular lymphnode and axillary lymphnode with 74.32%, 8.78% and 8.78% of cases respectively. Rai N N et al2 and Nama S et al4 also observed cervical lymphnode to be commonly involved with 57% and 80.99% of cases respectively.
In the present study, 60.81% of cases accounted for Metastatic Squamous cell carcinoma deposits, followed by Metastatic Adenocarcinoma deposits in 19.59% of cases and in suspected cases of primary - Upper Aerodigestive tract was the commonest site. Study done by Goel N M et al1 and Nikethan B B8 et al also showed Metastatic Squamous cell carcinoma deposits, followed by Metastatic Adenocarcinoma deposits which was observed in 75%, 23% and 65%, 14% of cases respectively. Prasad S et al3 in their study found suspected primary site to be Upper Aerodigestive tract in 84.03% of cases. On the contrary to our observations, in some of the other studies metastatic adenocarcinoma was the most common subtype than squamous cell carcinoma.10, 9
Distinction between Metastatic adenocarcinoma deposits and Poorly differentiated squamous cell carcinoma can be difficult, especially when atypical cell clusters show thick nuclear membrane and prominent nucleoli. In our study also, there was a case of Metastatic adenocarcinoma deposits, but the primary tumor on histopathology was found to be Poorly differentiated Squamous cell carcinoma in esophagus. Diagnostic dilemma also occurs in cystic change/ necrotic lymphnode, thus one should always keep Metastatic Squamous cell carcinoma deposits and Metastatic Papillary thyroid carcinoma deposits as the differential diagnosis in their mind. Hence; along with microscopic examination of smears, clinical and radiological findings should be used in conjunction with FNAC.
Meticulous screening of smears as well correlation with clinical and radiological parameters is of utmost importance in Fine needle aspiration cytological diagnosis of metastatic lymphadenopathy.
Conclusion
In the present study, metastatic squamous cell carcinoma deposits were common. Cervical lymphnode was the commonest lymphnode involved; followed by supraclavicular, axillary and inguinal lymphnode. FNAC is an easy, rapid, relatively safe and non-expensive diagnostic modality. It is useful for the early diagnosis of metastatic lymphadenopathy in a developing country with resource challenged environment. It is not only useful in detecting secondaries where primary tumour is evident or is of unknown origin, but also helps in monitoring response to therapy.
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