Histopathological and immunohistochemical study of lymphnodal biopsies

Introduction: Diseases affecting lymph nodes form a wide range of spectrum, from simple infection to malignant pathology. A panel of IHC markers is decided based on morphologic differential diagnosis. Aims and Objectives: To study the incidence of lymph nodal lesions with respect to age and sex and their different histopathological patterns. To use Immunohistochemistry (IHC) for sub typing of neoplastic lesions. Materials and Methods: This study was done for a period of two and a half years in the Department o f Pathology, from Jan 2017 to June 2019. All the specimens received were fixed in 10% formalin and routinely processed and stained with Hematoxylin and Eosin (H&E.) Results: A total of 230 lymph node biopsies were studied. Age distribution varied from 3 to 83 years with female preponderance. Non – Neoplastic lesions were common comprising of 120 cases (52%) while neoplastic lesions were 110 (48%). Among non neoplastic lesions reactive lymphadenitis (23%) was common followed by tuberculous lymphadenitis (21%). In neoplastic lesions, metastatic diseases (20%) predominated. IHC was done wherever necessary for subtyping of lymphomas and also to differentiate lymphoma from carcinoma. Conclusion: Lymph node biopsy with IHC plays an important role in establishing the cause for lymphadenopathy and thus aids in therapy. © 2020 Published by Innovative Publication. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by/4.0/)


Introduction
Lymph node is one of the major anatomic components of the immune system. Because normal immune response leads to proliferation and expansion of one or more of the cellular components of lymph nodes, it leads to significant lymph node enlargement. 1 Lymphadenopathy is a common clinical problem and biopsies are usually undertaken to determine the cause of nodal enlargement, which may be neoplastic or nonneoplastic. 2 Lymph node lesions form a wide range of spectrum from benign reactive changes to lymphoma and metastatic deposits. 3 Lymphadenopathy is either generalized or localized, Generalized lymphadenopathy is seen in a large number of systemic illnesses while localized lymphadenopathy is more often seen with local infection or malignancy. 4 First step in developing better therapies is the recognition of distinct specific disease entities by pathologists. Since there is no specific treatment for most forms of reactive lymphadenopathy, even a non-specific diagnosis is helpful, because the main aim is to exclude a malignant process and treatable causes. 4 Immunohistochemistry helps in the sub typing of the lymphomas into different categories which have a therapeutic and prognostic importance. 5 We aim to study the incidence with respect to age and gender along with histopathological patterns of lymph nodes received in our department over a period of two and a half years https://doi.org/10.18231/j.achr.2020.014 2581-5725/© 2020 Innovative Publication, All rights reserved. 70

Materials and Methods
A total of 230 lymph nodal biopsies were recieved in the department of pathology from January 2017 to June 2019.

Inclusion criteria
Excision biopsies of lymph nodes were included in the study

Exclusion criteria
Cases with inconclusive diagnosis due to lack of adequate material were excluded. All the specimens were formalin fixed, paraffin embedded and stained with H and E stains.
IHC using relevant antibodies was done according to histomorphological features wherever needed. Immunohistochemical studies were carried out with 5µ paraffin sections. The antibodies included CD3, CD15, CD20, CD30, Leukocyte Common Antigen (LCA), Pancytokeratin and Bcl-2. The lymphomas were classified according to World Health Organisation classification of hematolymphoid malignancies 2017. All cases of non Hodgkin lymphomas were subjected to B and T cell markers for sub typing . Likewise most of the Hodgkin lymphomas were subjected to immunophenotyping using CD 45, CD 15 and CD 30. In cases of ambiguity Pancytokeratin was also used to exclude metastatic deposits.

Results
This study included a total of 230 lymph node biopsies. The age range was 3-85 years and maximum cases were seen in the 21-30 years age group.
The non neoplastic lesions were common in the age group 21-30 years and among them reactive lymphadenitis was the most common accounting to 26 % (61 cases). In these 61 cases, chronic non specific lymphadenitis (18%) was common followed by follicular hyperplasia (5%) and sinus histiocytosis (3%). Granulomatous lymphadenitis was the second common non-neoplastic lesion comprising 22% (49 cases) in which tuberculosis (15%) (Figure 1 A) was the most common and others were of unknown etiology. (Table 1 ) Non neoplastic lesions also included 3 cases of Kikuchi lymphadenitis ( Figure 2B), 2 cases of Castleman's disease of hyaline vascular type ( Figure 3C) and 1 case each of myeloid metaplasia, a ngiomatous lymph nodal hamartoma (Figure 4 D) and lipomelanotic lymphadenopathy. (Table 1) In the 110 neoplastic lesion s, metastatic diseases were common accounting to 20% (47 cases) followed by 19% (44 cases) of Non Hodgkin lymphomas and 9% (19 cases) of Hodgkin lymphomas. (Table 2).
In these neoplastic lesions 12 cases had a differential diagnosis of lymphoma/ metastatic lesion on histopathology which were later confirmed with the aid of Immunohistochemical markers CD 45 and Pancytokeratin, of which 5 cases were diagnosed as poorly differentiated adenocarcinoma and 7 cases were non Hodgkin lymphoma.
Metastatic lesions were common in the age group 61-70 years and there was a female preponderance. Among them Squamous cell carcinoma (20 cases) (Figure 2A In the 44 cases of non Hodgkin lymphoma, 39 cases were of diffuse large cell lymphoma ( Figure 3A), 2 cases were follicular lymphoma ( Figure 4A) and 1 case each of small cell lymphocytic lymphoma ( Figure 3B), anaplastic large cell lymphoma and T cell lymphoma ( Figure 4C). Non Hodgkin lymphomas were common in the 41-50 years age group with an age range of 10 to 85 years. Immunohistochemistry was done in 40 cases in which 35 cases were positive for CD 20 ( Figure 3C) and negative for CD 3 ( Figure 3D). 2 cases were positive for BCl2 (Figure 4 B) and 2 cases were positive for CD 3 ( Figure 4D). The remaining 4 cases were reported as diffuse large B cell lymphoma and IHC was not done for these cases due to economic constraint.
Hodgkin lymphomas include 19 cases, 18 cases were of classical type and 1 case was lymphocyte predominant type. In classical type of Hodgkin lymphoma, 15 cases were of mixed cellularity sub type ( Figure 5A), 2 cases of nodular sclerosis sub type ( Figure 5B) & 1 case of lymphocytic depletion. They were seen in age group 51-60 years. These 18 cases of classical Hodgkin lymphoma were confirmed by positivity for CD15 and CD30 as shown in (Figure 5 C&D) Discussion This study included a total of 230 lymph nodal biopsies with different histopathological patterns and Immunohistochemistry was done in lymphomas for confirmation and also to differentiate lymphoma from carcinoma.
In our study maximum number of cases were seen in the age group of 21-30 years which was similar to a study done by Rajashri P et al 1 and in other studies done by Arun Roy et al 2 and Pagaro PM et al, 3 11-30 years and 41-50 years age groups were involved respectively. Granulomatous -tuberculosis Others 35(15%) 14(07%) 3.
Angiomatous lymphnodal hamartoma 01(0.5%) Total 120 There was a slight female preponderance in the present study and male to female ratio was 1:1.1 which was co rrelating with studies done by Rajashri P et al, 1  The predominant site of lymph node biopsy was cervical followed by inguinal which was similar to studies done by Komal et al 4 Hussain MI et al, 7 Saraswat A et al 8 and Rajashri P et al 1 and Khanday SA et al. 9 The preponderance of cervical lymphadenopathy may be related to its location near a common primary site of infections and malignancy that are drained through this single channel. 10 In the present study non neoplastic lesions were more common compared to neoplastic lesions, and these results were consistent with studies done by Rajashri P et al 1 Komal et al 4    et al. 2 In the non neoplastic lesions reactive lymphadenitis was common as bacterial and viral infections can lead to reactive lymphadenopathy followed by tuberculous lymphadenitis. This was similar to studies done by Rajashri P et al 1 and Pagaro PM et al. 3 In studies done by Komal et al 4 and Hussain MI 7 et al tuberculous lymphadenitis was reported as the predominant cause of lymph nodal enlargement.
Metastatic deposits were common in neoplastic lesions accounting to 20%, followed by Non Hodgkin lymphomas (19%) and Hodgkin lymphomas (9%) this was similar to studies done by Rajashri P et al 1  Among the metastatic lesions most common type was Squamous cell carcinoma (20 cases). This was similar to a study done by Pagaro PM et al 3 and discordant with studies done by Rajashri P et al 1 and Arun Roy et al 2 where ductal carcinoma of breast and adenocarcinoma deposits were common respectively.
The second common type of metastatic lesion was papillary carcinoma of thyroid (13 cases) which was discordant with studies done by Rajashri P et al 1 and Arun Roy et al 2 Age and gender play an important role in prognosis and treatment outcomes of lymphomas.
Non Hodgkin lymphomas comprised 44 cases (19%) and were found to be prevalent in 51-60 years age group. This was in accordance with a study by Vallabhajosyula et al 12 where the peak incidence was between 41-67 years and in a study by Roy et al 2 it was reported in 51-60 years age group.
In Non Hodgkin lymphomas, Diffuse large B cell lymphoma was the predominant type. This was similar to studies done by Rajashri P et al, 1 Arun Roy et al, 2 where as in a study done by Pagaro PM et al 3 follicular lymphoma was common. Immunologic characterisation of NHL B cell lymphomas are constantly more common worldwide. 3 Mixed cellularity was the common subtype in Hodgkin lymphomas which was similar to a study done by Khanday SA et al, 9 whereas in study done by Arun roy et al 2 nodular sclerosis was the common subtype.

Conclusion
The present study highlights the importance of lymph node biopsy and immunohistochemistry in establishing the cause for lymphadenopathy. In this study maximum number of cases were seen in the age group of 21-30 years and there was a female preponderance. In non -neoplastic lesions, reactive lymphadenitis was common followed by tuberculosis. In neoplastic lesions, metastatic diseases were common followed by Non Hodgkin lymphomas and Hodgkin lymphomas.

Source of funding
None.

Conflict of interest
None.