|Year : 2020 | Volume
| Issue : 4 | Page : 192-195
Primary salivary gland lymphomas: A case series
Sohaila Fatima1, Rabab Nasir Mohamed Badri2, Wajih Ahmed Siddiqui3, Abdulrahman Alshehri3
1 Department of Pathology, King Khalid University, Aseer Central Hospital, Abha, KSA
2 Department of Laboratory Medicine, Aseer Central Hospital, Abha, KSA
3 Department of Hemato-Oncology, Aseer Central Hospital, Abha, KSA
|Date of Submission||19-Jun-2020|
|Date of Acceptance||31-Oct-2020|
|Date of Web Publication||28-Dec-2020|
Dr. Sohaila Fatima
Department of Pathology, King Khalid University, Abha
Source of Support: None, Conflict of Interest: None
Salivary gland lymphomas are rare, constituting 1.7% of all salivary gland neoplasms. They are uncommon before 50 years of age predominantly involving parotid gland. The most common histopathological forms of non Hodgkin lymphoma include mucosa associated lymphoid tissue lymphoma followed by follicular lymphoma and diffuse large B cell lymphoma. A retrospective study was conducted in a tertiary health care centre over a span of six years on patients with salivary gland lymphomas. Their clinicopathological features, staging and treatment modalities were determined. The mean age was 63.3 years with four males and two females. All patients had parotid gland involvement with one showing simultaneous involvement of submandibular gland. Histopathologically there were three cases of low grade B-cell lymphoma, two cases of high grade lymphoma and one case of Hodgkin lymphoma. Three patients were found in early stage and three in advanced stage disease. Lymphomas must be considered in the differential diagnosis of a salivary gland swelling although they are quite uncommon. They predominantly involve parotid gland. The selection of treatment modalities is based on histologic subtyping and staging of lymphoma with better prognosis as compared to other extranodal non Hodgkin lymphoma.
Keywords: B cell lymphomas, lymphoma, salivary gland
|How to cite this article:|
Fatima S, Badri RN, Siddiqui WA, Alshehri A. Primary salivary gland lymphomas: A case series. Libyan J Med Sci 2020;4:192-5
| Introduction|| |
Lymphomas are malignant hematopoietic neoplasms that produce masses in lymph nodes or other tissues. They could be Hodgkin lymphoma (HL) and non-HL (NHL). Extranodal non-HLs (ENHL) are predominantly seen in the gastrointestinal tract, followed by the head and neck region. Lymphomas constitute 5% of all malignant tumors in the head and neck region. The salivary glands serve as the site for 12% of extranodal lymphomas of the head and neck region and extranodal lymphomas represent 1.7% of all salivary gland neoplasms. Primary salivary gland lymphoma (PSGL) manifesting initially in the salivary gland is more common than secondary lymphoma as part of disseminated disease. The parotid gland is predominantly affected (70%), followed by the submandibular gland (20%) and the minor salivary gland (10%). Majority of PSGL clinically present as painless masses and are of B-cell type. Treatment includes surgical modalities, radiotherapy, and chemotherapy. Here, we present a case series of six patients with PSGL.
| Materials and Methods|| |
A retrospective study was conducted in the histopathology section of the Department of Laboratory Medicine of Aseer Central Hospital, Abha, Kingdom of Saudi Arabia, from January 2014 to December 2019 on tissue specimens from salivary gland lymphomas. The histopathological diagnosis was made according to the World Health Organization classification. All specimens were stained with H and E and immunohistochemical markers cytokeratin, leukocyte common antigen, CD3, CD5, CD10, CD15, CD20, CD 21, CD30, BCL2, BCL6, Cyclin D1, and other markers as necessary. The clinical data were obtained from the records of the patients.
| Results|| |
We had six patients who were diagnosed with PSGL. The age varied from 47 to 78 years with a mean of 63.3 years. There were four males and two females, with all patients having parotid gland involvement and one having simultaneous involvement of the submandibular gland. All presented with painless parotid masses without facial nerve involvement. None of the patients had B symptoms (i.e., fever, night sweats, or weight loss). No history of Sjogren's syndrome or any other autoimmune disorder was seen in our patients. Histopathologically, we had three cases of low-grade B-cell lymphoma (one mucosa-associated lymphoid tissue lymphoma [MALToma] [Figure 1], one follicular lymphoma (FL) [Figure 2], and one nonspecific), two cases of high-grade diffuse large B cell lymphoma (DLBCL) [Figure 3], and one case of HL [Figure 4]. Three patients were found in early-stage and three in advanced stage disease. Four patients received chemotherapy, one had surgical resection and is on follow-up and one was lost to follow-up. [Table 1] shows the clinical data of our patients.
|Figure 1: (a) Section shows infiltration of the parotid gland by low-grade lymphoma cells (b) CD20 positivity in malignant cells|
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|Figure 2: (a) Section shows infiltration of glandular tissue by follicular arrangement of malignant cells (b) B cell lymphoma 2 positivity in follicular malignant cells|
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|Figure 3: (a) Diffuse large B cell lymphoma of the parotid gland (b) CD20 positivity in malignant cells|
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|Figure 4: (a) Hodgkin lymphoma of intraparotid lymph node (b) CD15 positivity in mononuclear cells|
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| Discussion|| |
Lymphomas are malignant lymphoid neoplasms that arise as discrete tissue masses. They are predominantly nodal. HL is differentiated from all other forms which constitute the NHL. Lymphoma in a salivary gland could be a part of a systemic disease or the first evidence of lymphoma. The parotid gland contains intraglandular lymph nodes, and lymphoma may arise in glandular parenchyma (extranodal lymphoma) or within the intraparotid lymph nodes (nodal lymphoma). It is often difficult to distinguish between the two because intraparotid lymph nodes may contain salivary gland inclusions that can undergo proliferation in lymphoma. The major salivary glands are affected in only 5% of all primary extranodal lymphomas. The parotid is the most common salivary gland involved, although primary parotid lymphomas account for only 0.87% of all NHL cases. This being the reason of its rare suspicion before biopsy or surgical removal.
PSGL should be considered if the disease presents clinically with glandular involvement, histological involvement of the gland parenchyma, and not only adjacent lymph nodes or soft tissue with confirmation of the malignant nature of the lymphoid infiltrate. The parotid gland involvement by lymphoma is related to its anatomy which is rich in lymph nodes and lymphoid tissue. An increased risk of a lymphoma is found in patients with congenital or acquired immunodeficiency. Sjogren's syndrome was found to be associated with a 1000 fold increase in the risk of parotid gland marginal zone lymphoma and a 6.5 fold increase in the risk of NHL. Patients in late adulthood with a median age of 57–63 years with slight female predominance are usually affected by SGL. In our study, the age varied from 47 to 78 years with a mean of 63.3 years and male: female ratio being 2:1.
The large majority of PSGL are of B-cell derivation and the most common subtypes being MALToma, FL, and DLBCL. We had two cases of DLBCL and one case each of MALToma, FL, nonspecific low-grade B-cell lymphoma, and HL. Extranodal marginal zone lymphoma of MALToma is an indolent mature B cell neoplasm showing architectural similarities with reactive MALTomas occurring in various extranodal sites. They often arise against a background of Mikulicz disease or other immune-mediated diseases. In our cases, none had immunological disease. They have an excellent long-term prognosis. FL shows a follicular architecture and represents the neoplastic counterpart of germinal center B lymphocytes. The t (14;18) (q32;q21) chromosome translocation deregulates BCL-2 leading to its overexpression in neoplastic follicles. DLBCLs are aggressive tumors that are rapidly fatal without treatment. These are molecularly heterogeneous with frequent dysregulation of BCL-6, a transcriptional repressor that is required for the formation of normal germinal centers. HL is a malignant lymphoma in which Reed–Sternberg cells or mononuclear cells are present in a characteristic background of reactive inflammatory cells. HL is very rare in salivary glands, and in our case, it originated in intraparotid lymph node and it was a classical type.
Lymphoma must be considered in the differential diagnosis of salivary gland swelling. The diagnosis is often overlooked because of the rarity and indistinct radiological features and patients are often subjected to unnecessary procedures leading to delay in diagnosis. Parotid lymphomas are more likely to be of low grade but tend to be more aggressive than MALT lymphomas. They demonstrate better prognosis in comparison to other types of extranodal lymphomas. The selection of treatment modalities is on the basis of the histologic subtype and stage of lymphoma. Radiation therapy is the treatment of early-stage parotid NHL. For early-stage MALToma, complete excision of the tumor through superficial parotidectomy has similar survival outcome. However, for DLBCL, survival is higher with combined treatment versus single treatment. Four of our patients received chemotherapy, three are in remission with one still on treatment, one had surgical resection and is on follow-up, one patient was lost to follow-up.
| Conclusion|| |
Lymphoma must be considered in the differential diagnosis of salivary gland swellings. They are seen mostly after 50 years of age. PSGL are uncommon tumors predominantly involving parotid glands as painless masses. The most common histopathological forms of NHL include MALToma, FL, and DLBCL. The selection of treatment modalities is based on histologic subtyping and staging of lymphoma with better prognosis as compared to other ENHL.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]