Parotid lymphoma: a review of clinical presentation and management. Oral Surg Oral Med Oral Pathol Oral Radiol. 2014;118:e1-e5. [PMID: 24405648 DOI: 10.1016/j.oooo.2013.10.013]

Current evidence on diagnosis and treatment of parotid gland lymphomas: a systematic review

BACKGROUND AND PURPOSE

Parotid gland lymphoma (PGL) is a rare and challenging diagnosis. Different lymphomas can develop in the parotid gland, with the most common being the mucosa-associated lymphoid tissue (MALT) lymphoma, which originates directly from the glandular parenchyma. Other histologic subtypes arise from both intraglandular and extraglandular parotid lymph nodes. A consensus on diagnosis and treatment of PGL is still lacking, and published data is scarce and heterogeneous.

METHODS

We performed a systematic review of the literature, including studies published after 2001, when the WHO classification of lymphoid tumours was introduced.

RESULTS

Twenty retrospective studies were included in the analyses, eight of which focused exclusively on MALT lymphomas. Final analysis included 612 cases of PGL, with a 1.68:1 F/M ratio. MALT lymphoma was the most common histology, followed by follicular and diffuse large B-cell lymphoma. Most cases were low stages (IE/IIE acc. Ann Arbour, 76.5%) and only 10% of patients presented with symptoms, most commonly pain (4.8%) and B symptoms (2.2%). A high prevalence of associated autoimmune diseases was found, particularly Sjögren's syndrome, that affected up to 70% of patients with MALT lymphoma. In most cases diagnosis was achieved through parotidectomy (57.5%), or open biopsy (31.2%). Treatment strategies were either surgical, non-surgical or a combination of modalities. Surgery as a single-modality treatment was reported in about 20% of patients, supposing it might be a valuable option for selected patients.

CONCLUSIONS

Our review showed that the diagnosis and treatment of PGLs is far from being standardized and needs further, more homogeneous reports to reach consensus.

Warthin’s Tumor of the Parotid Gland With Degeneration to Diffuse Large B-cell Lymphoma: A Case Report and Review of Literature

Parotid gland neoplasms are rare; some benign lesions, such as Warthin's tumor (WT), can present as malignant degeneration to carcinomas or, even rarer, to lymphomas. In the literature, there are fewer than 30 reported cases of primary lymphoma of the parotid gland. We present a case of a 65-year-old male patient with a first diagnosis of WT of the parotid gland who later presented a tumor recurrence and underwent a second surgery, reporting diffuse large B-cell lymphoma of the parotid gland. He underwent a right parotidectomy and chemotherapy, and at his 5-month follow-up, he remains free of recurrence. These tumors may look clinically like benign tumors. However, it is essential to be always alert to detect potentially malignant neoplasms and to emphasize examining the lymphoid component of WT to have an early-stage diagnosis of possible lymphomas and treat them before morbidity and mortality increase.

Efficacy of Surgery in Patients with Stage I Primary Parotid Gland Lymphoma: A Population-Based Study

Background. Limited and controversial evidence is available on the efficacy of surgery for patients with stage I primary parotid gland lymphoma. Thus, we aimed to investigate whether surgery can enhance the prognosis of patients with stage I primary parotid gland lymphoma using large sample data. Methods. From 1998 to 2015, we searched the Surveillance, Epidemiology, and End Results (SEER) program database and extracted information regarding patients with stage I primary parotid gland lymphoma; we classified these patients into surgery and nonsurgery groups. We calculated overall survival (OS) and cancer-specific survival (CSS) using Kaplan–Meier curves and log-rank testing. Propensity score matching (PSM) analysis was also used to further account for confounding variables before comparing the OS and CSS again. We used the COX proportional hazard regression model in both multivariate and univariate analyses. Results. We enrolled 918 patients with stage I primary parotid gland lymphoma, among which 656 (71.5%) patients underwent surgery. Before PSM, the surgery group had better OS (hazard ratio (HR) = 0.673, 95% confidence interval (CI): 0.519–0.873, and $p=0.003$ ) and CSS (HR = 0.595, 95% CI: 0.403–0.879, and $p=0.008$ ) than the nonsurgery group. After PSM, surgery was still a beneficial factor for OS (HR = 0.569, 95% CI: 0.399–0.810, and $p=0.002$ ) and CSS (HR = 0.384, 95% CI: 0.220–0.669, and $p=0.001$ ). Furthermore, in univariate and multivariate analyses, total parotidectomy significantly increased OS ( $p=0.001$ and $p=0.021$ , respectively) and CSS ( $p=0.001$ and $p=0.037$ , respectively). Conclusions. In summary, the prognosis of patients with stage I primary parotid gland lymphoma can be significantly improved by surgery. Moreover, total parotidectomy was a protective factor for OS and CSS before and after PSM analysis, suggesting that surgery acts as a significant component in multimodal therapy for early primary parotid gland lymphoma.

Advanced magnetic resonance imaging findings in salivary gland tumors

Salivary gland tumors (SGTs) make up a small portion (approximately 5%) of all head and neck tumors. Most of them are located in the parotid glands, while they are less frequently located in the submandibular glands, minor salivary glands or sublingual gland. The incidence of malignant or benign tumors (BTs) in the salivary glands varies according to the salivary gland from which they originate. While most of those detected in the parotid gland tend to be benign, the incidence of malignancy increases in other glands. The use of magnetic resonance imaging (MRI) in the diagnosis of SGTs is increasing every day. While conventional sequences provide sufficient data on the presence, localization, extent and number of the tumor, they are insufficient for tumor specification. With the widespread use of advanced techniques such as diffusion-weighted imaging, semi-quantitative and quantitative perfusion MRI, studies and data have been published on the differentiation of malignant or BTs and the specificity of their subtypes. With diffusion MRI, differentiation can be made by utilizing the cellularity and microstructural properties of tumors. For example, SGTs such as high cellular Warthin’s tumor (WT) or lymphoma on diffusion MRI have been reported to have significantly lower apparent diffusion values than other tumors. Contrast agent uptake and wash-out levels of tumors can be detected with semi-quantitative perfusion MRI. For example, it is reported that almost all of the pleomorphic adenomas show an increasing enhancement time intensity curve and do not wash-out. On quantitative perfusion MRI studies using perfusion parameters such as Ktrans, Kep, and Ve, it is reported that WTs can show higher Kep and lower Ve values than other tumors. In this study, the contribution of advanced MRI to the diagnosis and differential diagnosis of SGTs will be reviewed.

Primary diffuse large B-cell lymphoma of the major salivary glands: Increasing incidence and survival

BACKGROUND

Diffuse Large B-Cell Lymphoma (DLBCL) of the major salivary glands is a rare high-grade malignancy that often presents with vague symptoms. This study aimed to evaluate its incidence and prognosis on a population level.

METHODS

The Surveillance, Epidemiology, and End Results database was queried for cases of major salivary gland DLBCL.

RESULTS

896 patients had DLBCL affecting the parotid gland (78.3%) or submandibular gland (19.8%). The incidence was increasing at 1.5% (P = 0.005) per year from 1973 to 2016. 24.4% of patients underwent parotidectomy, 16% had biopsy, and the remaining provided no details of diagnostic method. Five-year disease-specific survival increased from 59.8% to 84.0%. Late-stage disease (HR = 1.7, P = 0.003) and female sex (HR = 2.1, P = 0.018) were associated with increased risk of mortality.

CONCLUSION

Despite the rising incidence of major salivary gland DLBCL, chemotherapy and radiation treatment has resulted in increasingly favorable survival outcomes. The otolaryngologist - head and neck surgeon continues to play a critical role in establishing the diagnosis of salivary gland DLBCL.

Imaging of head and neck mucosa-associated lymphoid tissue lymphoma (MALToma)

Marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALToma) arises in extranodal sites in the head and neck. Chronic inflammatory, infectious or autoimmune conditions are implicated in its pathogenesis. Within the head and neck, MALToma is often multifocal and indolent and the imaging appearances may be mistaken for non-malignant disease in the head and neck. The aim of this article is to illustrate the varied radiological and clinical features of MALToma in the head and neck, an awareness of which is needed for timely and correct diagnosis to guide subsequent disease management.

Relative risk of positional and dynamic temporomandibular disc abnormality for osteoarthritis-magnetic resonance imaging study

Dynamic articular disc abnormality (wR, with reduction; woR, without reduction) is well known as the risk factor for temporomandibular joint osteoarthritis (TMJOA). However, there are few speculations on the potential risk of positional disc abnormalities for TMJOA. The purpose of this study was to investigate the relative risk of positional abnormality and dynamic abnormality of the temporomandibular disc for OA after the three-dimensional interpretation of all the sagittal and coronal planes of magnetic resonance (MR) data in a large dataset of consecutive subjects. Experimental samples consisted of images of 1356 TMJs of patients. A diagnosis of disc state was established in each TMJ utilising a 1.5T MR imaging scanner. A binary logistic regression analysis was performed to identify the significant associations between the outcome (dependent variable: the presence of OA) and the predictors (covariates: age, sex, dynamic disc state [the presence of woR], and 5 categories of the positional disc state [NA, no abnormality; SW, sideways; pADD, partial anterior; cADD, complete anterior; PDD, posterior]). Based on the result of the binary logistic regression analysis, the presence of woR showed an odds ratio of 14.1 (P < .05). In addition, compared with the joints NA, those with SW and cADD showed odds ratios of 5.62 and 10.88, respectively (P < .05). Despite the limitations of the study, in the positional disc abnormalities, sideways disc displacement and complete anterior disc displacement could be associated with the occurrence of TMJOA. All the coronal and sagittal MR images should be evaluated to assess intra-articular joint disorders accurately.

Lymphoma of the Sublingual Gland: Clinical, Morphological, Histopathological, and Genetic Characterization

Background: Lymphoma of the sublingual gland is rare, representing 1% of all salivary gland lymphomas. In this case report, we present three new cases and compare them to previously published cases, with the aim of characterizing the clinical, morphological, histopathological, and genetic features of this type of malignancy.

Materials and Methods: We provide a clinical description of three cases along with a characterization of the microscopic features, including morphology, and immunohistochemistry. In addition, we analysed possible cytogenetic rearrangements with the use of fluorescence in situ hybridization (FISH).

Results: Case 1: A 61-year-old male presenting with a painless swelling of the floor of the mouth diagnosed as extranodal marginal zone lymphoma (EMZL) of the left sublingual gland. The patient is alive with no evidence of disease after his fourth treatment regimen following several relapses. Case 2: A 68-year-old female with a prior history of mantle cell lymphoma (MCL) presenting with a tender swelling of the left sublingual gland as well as the right submandibular gland. The lesions were diagnosed as relapsing MCL. The patient died of unrelated causes after 18 months of treatment. Case 3: A 75-year-old female presenting with a swelling of the floor of the mouth diagnosed as follicular lymphoma (FL) of the left sublingual gland. The patient received chemotherapy along with radiotherapy and was still alive 10 years after the diagnosis.

Conclusion: The three cases of sublingual gland lymphomas presented in this case report resemble lymphomas of other major salivary glands. The clinician should be aware of this type of malignancy and that the clinical presentation may not differ from benign lesions or other more common malignancies in this location.

Primary parotid gland lymphoma: pitfalls in the use of ultrasound imaging by a great pretender

The aim of this study was to highlight several misleading imaging and clinical aspects of parotid gland lymphoma, taking our personal experience and relevant literature reports into consideration. The records of all patients diagnosed with lymphoma in the parotid gland between 2005 and 2017 were examined retrospectively. Sixty-seven patients were included in this study. The mean age was 61.4 years. The most frequent histological entities were marginal zone B-cell lymphoma (31.3%) and follicular lymphoma (28.4%). The tumour was stage I in 35 cases (52.2%), stage II in 13 cases (19.4%), stage III in 11 cases (16.4%), and stage IV in eight cases (11.9%). B symptoms were seen in only three patients (4.5%). The diagnosis was made after parotidectomy in 51 cases (76.1%), by core needle biopsy in 14 cases (20.9%), and by means of open biopsy in the remaining two cases (3.0%). Parotid gland lymphoma represents a diagnostically challenging, multifaceted entity that can easily mimic both benign and malignant conditions. This entity should be included in the differential diagnosis of almost all types of parotid lesion, as it seems to play the role of a great pretender.

Relevance on the diagnosis of malignant lymphoma of the salivary gland

Malignant lymphoma originates from the lymphohematopoietic system. It can occur in any lymphoid tissue. Malignant lymphoma of the salivary gland is rare, but its incidence has increased in recent years. Its clinical- presentations are non-specific, and it is often manifested as a painless mass in a salivary gland, which can be accompanied by multiple swollen cervical lymph nodes. Confirmation of the diagnosis before an invasive procedure is difficult. Clinically, malignant lymphoma of the salivary gland tends to be misdiagnosed, leading to an inappropriate treatment plan and the ultimate delay in the optimal treatment of the disease. This article reviews the pathogenesis, clinical features, imaging findings, diagnosis, treatment and prognosis of malignant lymphoma of the salivary gland.

Pediatric follicular lymphoma of the parotid gland

Primary malignant lymphoma rarely presents as a mass in the salivary gland. It accounts for about 1% of salivary gland tumors. The lymphomas of the parotid gland are mainly non-Hodgkin’s lymphoma of B-cell follicular type. It usually occurs in male adults and is very rare in children. In contrast to the intractable disease course of adult parotid follicular lymphoma, when occurred in children or adolescent, its prognosis is very good when it is first treated with surgical excision. Thus, a solitary follicular lymphoma in an extranodal site that has occurred in children is termed separately as pediatric follicular lymphoma (PFL). We share our treatment experience of a 16-year-old PFL patient through surgical removal combined with superficial parotidectomy. In line with the few previous case reports of PFL, we suggest that active surgical removal should be undertaken for solitary, extranodal follicular lymphoma of the pediatric and adolescent population.

Multimodality fMRI with perfusion, diffusion-weighted MRI and 1 H-MRS in the diagnosis of lympho-associated benign and malignant lesions of the parotid gland

BACKGROUND

Differential diagnosis of the mucosa-associated lymphoid tissue lymphoma (MALToma) and tumor-like benign lymphoepithelial lesion (BLEL) in the parotid gland is difficult.

PURPOSE

To distinguish MALToma and BLEL with multimodality MRI including hydrogenproton magnetic resonance spectroscopy (¹ H-MRS), diffusion-weighted imaging (DWI-MR), and dynamic contrast-enhanced (DCE-MR), and evaluate each sequence.

STUDY TYPE

Retrospective.

POPULATION

Twenty-five patients with parotid tumor-like BLEL and 20 with parotid MALToma.

FIELD STRENGTH/SEQUENCE

1.5-T/T₁ WI, T₂ WI, single-voxel ¹ H-MRS, DWI-MR, and DCE-MR.

ASSESSMENT

All MR images were interpreted and agreed upon by two radiologists who were blinded to clinical information and histopathologic results. The imaging diagnoses were then compared to the histopathologic results.

STATISTICAL TESTS

Youden index was used to determine the optimized threshold value. The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficiency of different functional (f)MRI methods.

RESULTS

Fisher's exact test indicated a significant difference between the ¹ H-MRS images of the two lesions (P < 0.001). The sensitivity, specificity, and accuracy of positive choline (Cho) peak in ¹ H-MRS of parotid MALToma were 80%, 76%, and 77.7%, respectively. The mean apparent diffusion coefficient (ADC) was 0.992 × 10^-3 mm² /s in patients with parotid tumor-like BLEL and 0.634 × 10^-3 mm² /s in patients with parotid MALToma, and the difference was statistically significant (t-test, P < 0.001). Choosing the Youden index as 0.669 × 10^-3 mm² /s, the sensitivity, specificity, and accuracy of the assay were 78.9%, 95.8%, and 88.4%, respectively. Assuming that time-intensity curve (TIC) type I indicated parotid MALToma (positive), and type II and type III indicated parotid tumor-like BLEL (negative), the sensitivity, specificity, and accuracy of time-to-peak (TTP) and initial slope of increase (ISI) in diagnosing MALToma were 94.1%, 95.2%, and 94.7%, respectively. Combining methods of TTP, ADC, and Cho peak reached the highest AUC (1.000).

DATA CONCLUSION

Combined use ¹ H-MRS, DWI-MR, and DCE-MR increased the accuracy of the differential diagnosis between these lesions to 100%. Cho peak in ¹ H-MRS, ADC less than 0.669 × 10^-3 mm² /s, TIC type I together indicated parotid MALToma.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:423-432.

Treatment of Parotid Non-Hodgkin Lymphoma: A Meta-Analysis

Purpose

This meta-analysis aimed to review the published outcomes of parotid non-Hodgkin lymphoma (NHL) pertaining to different treatment modalities.

Materials and Methods

A total of 48 journal articles published between 1993 and 2015, comprising 742 cases of parotid NHL, were initially evaluated. In total, 108 patients from 12 studies who had sufficient data for analysis, including age, tumor histopathology, treatment modality, and outcome at final follow-up, were included. Patients were randomly assigned to different categories on the basis of histopathology and treatment modality. Groups were compared using Kaplan-Meier survival curve analysis and the Mann-Whitney U test.

Results

Log-rank tests demonstrated that for early-stage (I and II) parotid NHL of all histopathology variants, radiation therapy significantly improved the survival rate versus chemotherapy (P = .043), as well as combined treatment with chemotherapy and radiation therapy (P = .023). For early-stage diffuse large B-cell lymphoma, combined treatment significantly improved survival versus single treatment (P = .028). No treatment was received by seven patients with early-stage mucosa-associated lymphoid tissue lymphoma after undergoing parotidectomy. When the clinical outcomes of these patients were compared with those of other patients with the same histology who underwent further treatment, no significant differences were noted in survival outcomes.

Conclusion

Radiation therapy seems to be a valid treatment of early-stage parotid NHL. However, for diffuse large B-cell lymphoma, survival was higher with combined treatment versus single treatment. For early-stage parotid mucosa-associated lymphoid tissue lymphoma, complete excision of the tumor through superficial parotidectomy may have similar survival outcome.

Malignant lymphoma on parotid gland: a clinical case

Non-Hodgkin's lymphoma on the parotid gland is a relatively rare occurrence among head and neck tumors. The mass of parotid gland lymphoma cannot be distinguished from other benign masses of the parotid gland; therefore, it is important to consider lymphoma in the differential diagnosis when examining parotid swellings and masses. Parotid gland lymphoma is most likely to be B-cell, non-Hodgkin's lymphoma of one of three types, which include follicular, marginal zone, and diffuse large B-cell, although other histologic patterns have been described. We present a review of a patient with diffuse large B-cell lymphoma (DLBCL) who presented to the Department of Oral and Maxillofacial Surgery of Pusan National University Hospital (Yangsan, Korea).