Contribution of Immunohistochemistry in the Diagnosis of Lymphomas

Objective: Making the interest of using immunohistochemistry clear in addition to histological test in the diagnosis of lymphomas. Methods: This is a retrospective study from January 2011 to June 2013 involving 18 cases of lymphomas collected in the teaching hospitals of Treichville and Yopougon. Results: 1) 38.88% diagnosis of LMNH B large-cell in histology against 38.88% LDGCB with IHC. 2) 11.11% diagnosis of LMNH small cell in histology against 11.11% with IHC. 3) 5.55% diagnosis of T lymphoma in histology against 27.77% diagnosis of T lymphoma with IHC. 4) 5.55% diagnosis of follicular lymphoma in histology against 11.11% diagnosis of LF with IHC. 5) 11.11% diagnosis of Burkitt lymphoma in histology against 5.55% diagnosis of LB with IHC. 6) 5.55% diagnosis of medullary hypoplasia in histology against 5.55% diagnosis of Hodgkin’s disease. Our results confirm the contribution of immunohistochemistry in the diagnosis of lymphomas in addition to histological test. This is striking, especially as there is 27.77% of T lymphoma with immunohistochemistry against only 5.55% with histology.


Introduction
The term lymphoma refers to anatomo-clinical entities that are a tumor proliferation of lymphoid tissue characterized by the multiplication of an abnormal Open Journal of Blood Diseases lymphocyte clone.We distinguish Hodgkin's disease from non-Hodgkin's lymphomas.
The diagnosis is based on the multidisciplinary morphological analysis: which is interested in the size of the cell (small cell in low-grade or large-cell LMNH in high-grade LMNH) and the architecture of the immunological sampling: searching for the presence of Ag on cell membranes, and cytogenetics: searching for chromosomal abnormalities (t (11,14) in mantle NHNH, t(14, 18) in follicular LMNH) and/or molecular: searching for proto-oncogene.
The morphological study may prove to be insufficient for diagnosis in the case of poorly differentiated tumor or remodeled tumor (necrosis) or low tumor cell sampling as well as the nature of the B or T lymphomatous cell involving the use of immunohistochemistry.To determine monoclonality with the presence of an immunoglobulin light chain, immunohistochemistry makes it possible to establelish a precise phenotype with the identification of B or T lymphocyte nature or Natural-killer cells.Our study aims at showing the contribution of immunohistochemistry in the diagnosis of non-Hodgkin lymphoma in our working conditions.

Patients and Methods
This was a descriptive retrospective and analytical study conducted in the clinical hematology department of the teaching hospitals of Yopougon and Treichville between January 2011 and June 2013.
This study involved patients diagnosed with non-Hodgkin's lymphoma; the patients in whom the diagnosis was confirmed by histological analysis and who had undergone an immunohistochemical analysis were selected.
The sampling was systematic random, including 18 patients for whom immunohistochemistry was performed.Patients with non-Hodgkin lymphoma and who did not go through an immunohistochemistry test were excluded from the study.
The data was collected using a survey form that was prepared, specifying for each patient epidemiological, clinical, histological and immunohistochemical data.These data were collected from medical records (age, gender, occupation).
The clinical variables studied were the type of affection (ganglionic or extra ganglionic) and the general signs: (fever, weight loss, profuse sweat).
The proposed diagnosis was established after the histological study carried out in the laboratory of anatomical pathology and this histological study consisted in the recording of the sample, verification of the good fixation of the sample, macroscopic examination of the sample (weighing, measuring and cutting), dehydration of the components, the paraffin impaction of the components, carrying out microtome cutting, lamellas staining after heating to deparaffinize them and finally the assembly of the lamellas for the interpretation.
The diagnosis chosen was that obtained after the immunohistochemical study, which consisted in demonstrating Ag in situ on cell or tissue preparations using Open Journal of Blood Diseases labeled Ac.It applied to samples that were fixed and included in paraffin as well as to frozen tissues.These samples corresponded to the tissues that had already been examined in histology.

Results
The general characteristics (epidemiological and clinical) are presented in Table 1 and biological in Table 2.
Out of the 18 patients, the average age of the study population was 41 years with extremes of 4 and 73 years.The study population was composed of 12 women and 6 men with a sex ratio of 0.5.The reason for consultation is dominated by adenopathies in more than 88% cases.Most of our patients consulted at a stage III and IV of ANN ARBOR (66.67%).More than 66.7% of the studied population had a sign of biological evolution.Most of the patients in our study were at an extensive stage of their disease.This data are illustrated in Table 1, Figure 1, Tables 2-5.
As regard the comparation between histological analysis and immunohistochemical analysis, we found one cas of lymphoma T at histological analysis against five cas of lymphoma T at immunohistochemical analysis.These data were presented in Tables 6-8.

Discussion
Different observation led us to the following comments: In our sampled group most affected gender was women (66.7%) over men (33.3%) with a sex ratio of 0.5 contrary to what is described in the documentation describing a sex ratio of 1, 3 to 2 in favor of the man.this could be justified by our very selective and reduced sample.
Over 60% of our sampled population were housewives, farmers and students.

Clinical Explanation
The clinical picture was mainly characterized by adenopathy infection in more than 88% cases followed by weight loss in 66.7% cases and fever in more than LDGCB is defined as a diffuse proliferation of large B lymphomatosis cells, of which nucleus is at least twice larger than the nucleus of a normal lymphocyte or larger than the one of a macrophage.
About the centroblastic variant, the cell population is mainly composed of a range of medium to large elements with a rounded nucleus and clear chromatin bearing two to four nucleoli classically contiguous to the nuclear membrane.The cytoplasm is scanty and discreetly basophilic and often, cells of which nuclei have incisions melts to it.
The histological aspect from our study matches with description reported in documentation [5] [6] [7].
2) From IHC aspect The immunohistochemistry examination confirmed the LDGCB diagnosis with 7 patients (case1, case 4, case 6, case 7, case 8, case 9, case 10) and positive The IHC performed as part of study confirmed the LDGC diagnosis with 7 patients by specifying the nature B proliferations.

Small Cell LMNH (Centrocytic) with Small Malt Cell 1) From histologic aspect:
The histological diagnosis of non-Hodgkin's small cell lymphoma was performed over 4 patients (case 2, case 3, cases 5 and 15).
Diffuse lymphoma with small Malt cell, centrocytic and small cell B.
The histological description matches with documentation.
2) From IHC Aspect Open Journal of Blood Diseases The microscopic description matches with observation made on our patient.
2) From IHC aspect: IHC analysis confirmed the diagnosis of follicular lymphoma:

T Lymphoma 1) From histologic aspect
The histological diagnosis of T-cell lymphoma has been issued to a patient (case 13).The morphological aspect is often characteristic and displaying a fading architecture with a diffuse polymorphic proliferation.
In our sample group, histological aspect has not been described.

Hodgkin's Disease 1) From histologic aspect
The histology led to diagnose bone marrow hypoplasia to a patient (case 17).

2) From IHC aspect
On the said patient, the IHC analysis has rather enabled the diagnosis of a Hodgkin's disease with the positive antibodies, CD20+, CD30+ and CD3− [11] [12].

Conclusion
Results from our analysis confirm that the contribution of immunohistochemistry in the diagnosis of lymphomas associated with histological examination is fundamental, mainly as only immunohistochemistry can be used to diagnose T lymphomas.From this point of view, immunohistochemistry results reveal the 27.77% prognostic of T lymphocytes impact in immunohistochemistry, compared with only 5.55% of immunohistochemistry in histology.
This work indeed shows the important role of IHC in the diagnosis of lymphoid haemopathies [lymphoma] alongside morphological cytological and anatomo-pathological analyzes.They are all complementary and their request must be part of a logical approach with collaboration between biologists and practitioners.
In addition, equipment and training of our laboratory staff in modern diagnostic techniques is essential to ensure not only a good patient care but a minimization of the cost of examinations that will no longer need to be shipped.

1 )
55% of cases.Patients were diagnose stage III and IV of ANN ARBOR in more than 60% cases which represent the most advanced stage of the disease and matches with most authors that we read[1] [2] [4][5].From histologic aspect 7 patients were diagnose with histological diagnosis of large-cell non-Hodgkin's B-cell lymphoma (case 1, case 4, case 6, case 7, case 9, case 10, case 11).

1 )
Diffuse lymphoma was diagnose to 2 cases (case 2 and case 15) with CD20+CD15− and residual CD3 and refute to 2 cases (case 3 and case 5) Case 3 = CD3+CD34−CD5+BCL2+CD30 IHC helped correct small cell NHL histological diagnosis of 2 patients[5] From histologic aspect: Follicular lymphoma has been diagnose to one patient (Case 16).Most of the time, tumor proliferation architecture is nodular, made of follicles with ill-defined contours and closely contiguous to each other.

Table 1 .
Distribution of population by age.

Table 2 .
Distribution of population by occupation.

Table 3 .
Distribution of population according to the reason for consultation.

Table 4 .
Distribution of population through the ANN ARBOR stage.

Table 5 .
Distribution of population through the biological evolution stage.
[3]ut 50% of the sampled population was aged over 40 and this observation matches with documentation revealing that lymphoma is observed at any age but especially after 40 years[1][2][3].

Table 6 .
Distribution of the population according to the anatomo-pathological result.

Table 7 .
Distribution of the population according to the immunohistochemistry result.

Table 8 .
Spreading of population base on histologic and immunohistochemistry diagnosis.