Case report. A rare case of triple-hit diffuse large B-cell lymphoma of the parotid gland in a patient with Sjogren’s syndrome

Abstract

A rare case of triple-hit diffuse large B-cell lymphoma of the parotid gland in a patient with Sjogren's syndrome CASE REPORT INTRODUCTIONPrimary lymphoma of the salivary gland is rare, accounting for 2-5% of all salivary neoplasms. Diffuse large B-cell lymphomas (DLBCL) are uncommon, most salivary gland lymphoid malignancies being lowgrade lymphomas with MALT (mucosa associated lymphoid tissue) lymphomas being the most common. The majority of primary salivary gland DLBCLs appear to arise from MALT type lymphomas in a background of sialadenitis associated with autoimmune disorders, such as Sjogren syndrome [1][2][3][4] . The pathophysiology of Non-Hodgkin Lymphoma (NHL) is unknown. However, some risk factors are related to NHL development, such as acquired or druginduced immunodeficiency, some autoimmune diseases or Sjogren's syndrome 5 . Double and triple-hit B-cell lymphoma (DHL, THL) are rare lymphoma subtypes usually associated with poor prognosis. These specific subtypes are defined by two or three recurrent chromosome translocations: MYC/8q24loci, usually in combination with the t(14;18)(q32; q21) bcl-2 gene and/or BCL6 3q27 chromosomal translocation. Here, we present one case with diffuse large B-cell lymphoma associated with follicular lymphoma transformed to THL 6 . ABSTRACT BACKGROUND. Primary malignant lymphomas of the salivary gland are rare, accounting for 2% of salivary gland tumors and 5% of all extranodal lymphomas. The clinical presentation is not particularly characteristic, a feature that usually leads to diagnostic and treatment delays. CASE REPORT.We report a case of a parotid gland triple-hit diffuse large B-cell (DLBCL) lymphoma associated with follicular lymphoma in a 76-year-old female patient with a unique personal history, which included a diagnosis of Sjogren Syndrome and exposure to a toxic working environment with pesticides. Diffuse large B-cell lymphomas are uncommon given the fact that most lymphoid malignancies are low-grade lymphomas, with MALT (mucosa associated lymphoid tissue) lymphomas being the most common. Triple-hit DLBCL are extremely rare and the diagnosis can be challenging. Parotidectomy, as the first step, must be followed by histopathology and immunohistochemistry for final diagnosis and treatment.CONCLUSION. This case highlights the fact that B-cell lymphoma in the salivary gland can be unrecognized due to unspecific symptoms and requires immunohistochemistry studies for confirmation. It is important to recognize triple-hit lymphoma due to its worse prognosis and differentiated treatment. Patients with Sjogren syndrome have additional risk factors for progression to lymphoma.