Primary thymic MALT lymphoma in a patient with Sjögren's syndrome and multiple lung cysts: a case report

Primary thymic mucosa-associated lymphoid tissue (MALT) lymphoma with Sjogren's syndrome and diffuse cystic lung disease: a complex respiratory presentation of a multifaceted autoimmune disease

Mucosa-associated lymphoid tissue (MALT) lymphoma is a rare form of B-cell lymphoma which can potentially affect the stomach, spleen, salivary glands, skin, lungs, orbit, and, rarely, the thymus. Patients with Sjögren's syndrome (SjS) are at a 15-20 times increased risk of developing lymphoma compared to the general population.Here, we present a case of primary thymic MALT lymphoma and associated diffuse cystic lung disease, incidentally identified on routine chest imaging. Thymic MALT lymphoma has to date been reported primarily in women of Chinese origin, mainly without cystic lung disease. Diffuse cystic lung disease is well documented in women with SjS and the differential diagnoses also include lymphangioleiomyomatosis, which occurs almost exclusively in women.In the case presented, CT and positron emission tomography-CT showed a large hypermetabolic anterior mediastinal mass, as well as multiple thin-walled bilateral pulmonary cysts of widely varying sizes, without abnormal uptake. The patient was largely asymptomatic. Lung function testing, however, revealed restriction rather than obstruction, which is unusual in diffuse cystic lung disease. Biopsy of the mediastinal mass confirmed thymic MALT lymphoma which was treated medically with resultant improved lung function. This case highlights the association between SjS and MALT lymphoma, illustrates features which enable distinction between different causes of cystic lung disease in SjS, and comments on the multiplicity of SjS-related lung manifestations.

Molecular pathology assists the diagnosis of lymphoepithelial sialadenitis, Sjögren's syndrome and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue

Background/purpose

Lymphoepithelial sialadenitis (LESA), Sjögren's syndrome (SS), and salivary MALT lymphoma are diseases characterized by lymphoepithelial lesions, and the differential diagnosis between them in the salivary glands is challenging. This study aimed to explore clinicopathological and genetic characteristics of the three diseases.

Materials and methods

We retrospectively analyzed the clinical features, the histomorphology, immunohistochemistry, and genetic profiling by polymerase chain reaction (PCR) and next-generation sequencing (NGS).

Results

There included 68 LESAs, 25 SSs, and 62 MALT lymphomas. Ten cases relapsed in total, and 3 of MALT lymphomas died due to high-level transformation. Immunohistochemical double staining showed FCRL4 cells co-expressed Pax-5 and Ki-67, suggesting FCRL4 cells were proliferative B-cells. The expression level of the FCRL4 was significantly higher in MALT lymphoma than LESA and SS. The detection rates of clonal IGH, IGK, and IGL gene rearrangements in MALT lymphoma with a sensitivity of 83.33%. Monoclonal immunoglobulin gene rearrangements were confirmed in five suspected patients by NGS (100%).

Conclusion

FCRL4 B cells might play an important role in the formation of lymphoepithelial lesions and might be as a diagnostic positive marker of salivary MALT lymphoma. The application of multiple detection methods could significantly improve the diagnostic accuracy for MALT lymphomas from LESA and SS.

Incidence, mortality, and survival analyses of patients with thymic lymphoma

Objectives

To explore the clinical and prognostic characteristics of thymic lymphoma and the effects of current treatments on the prognosis.

Methods

Patients diagnosed as primary thymic lymphoma between 1975 and 2018 from the nine states of the US were identified, including Atlanta, Connecticut, Detroit, Hawaii, Iowa, New Mexico, San Francisco-Oakland, Seattle–Puget Sound, and Utah. Incidence and mortality rates were analyzed using SEER*Stat 8.3.9 software. Univariate and multivariate Cox regressions were performed to identify prognostic factors. The Kaplan–Meier curve and log-rank test were used to compare overall survival (OS) among different treatments.

Results

A total of 233 patients diagnosed as thymic lymphoma were identified, and eight of them were lost to follow-up or died upon diagnosis. The incidence of thymic lymphoma was 2.032 per ten million (95% CI: 1.777–2.312), and the mortality rate was 0.649 per ten million (95% CI: 0.508–0.817). Among the 225 patients with definite follow-up, 98 were males and 127 were females, with a median age of 33 years. The Cox regression results showed that age and pathological type were independent risk prognostic factors. The 5-, 10-, and 20-year OS were 80.0%, 77.5%, and 70.9%, respectively. For Ann Arbor stage I and II patients, there was no significant difference between the surgical group (N = 78) and the non-operative group (N = 65; P = 0.270). The radiotherapy group (N = 79) had better OS than the non-radiotherapy group (N = 64) in the first 25 years, and the prognosis in the later years was not significantly different (P = 0.051). The chemotherapy group (N = 37) had a significantly better prognosis than the non-chemotherapy group (N = 37; P = 0.020). Patients who received postoperative radiotherapy (N = 45) or who only received radiotherapy (N = 34) seemed to have better OS than that of patients who only received surgery (N = 33), although the difference was not significant (P = 0.063).

Conclusions

Age and pathological type were independent prognostic factors for thymic lymphoma. Surgical treatment had limited effects on OS, while both radiotherapy and chemotherapy could significantly improve the survival outcome.

Cancer incidence in primary Sjögren's syndrome: Data from the French hospitalization database

The relationship between cancer and primary Sjögren's syndrome (pSS) is uncertain. While the increased risk of hematological malignancies is well-known, data on the comparative incidence of solid neoplasms is conflicting. This study aimed to explore the associations between cancer and pSS. This nationwide population-based retrospective study from the French health insurance database (PMSI) evaluated patients hospitalized with new-onset pSS from 2011 to 2018 against age- and sex-matched hospitalized controls (1:10). The incidence of hematological malignancies and solid neoplasms was compared between the two groups. Mortality and multiple cancer incidence were also evaluated. Adjusted Hazard Ratios (aHR) calculations included confounding factors, such as low socioeconomic status. Among 25,661 hospitalized patients with pSS versus 252,543 matched patients (median follow-up of 3.96 years), we observed a higher incidence rate of lymphomas (aHR, 1.97 [95% CI, 1.59-2.43]), Waldenström macroglobulinemia (aHR, 10.8 [6.5-18.0]), and leukemia (aHR, 1.61 [1.1-2.4]). Thyroid cancer incidence was higher (aHR, 1.7 [1.1-2.8]), whereas bladder and breast cancer incidences were lower (aHR, 0.58 [0.37-0.89] and 0.60 [0.49-0.74], respectively). pSS patients with breast cancer exhibited a lower mortality rate. A limitation was that the database only encompasses hospitalized patients, and immunological and histological details are not listed. We confirmed the increased risk of hematological malignancies and thyroid cancers among patients with pSS. The lower risk of breast cancer suggests a role of hormonal factors and raises questions of the concept of immune surveillance within breast tissue. Epidemiological and translational studies are required to elucidate the relationships between pSS and cancer.

[Clinicopathological analysis of mucosa associated lymphoid tissue lymphoma secondary to Sjögren' s syndrome in salivary gland]

OBJECTIVE

To analyze the clinicopathological characteristics of mucosa associated lymphoid tissue (MALT) lymphoma secondary to Sjögren' s syndrome (SS) (SS-MALT lymphoma) in salivary gland and to explore the value of the combined application of histopathological morphology, protein expression and molecular phenotype in pathological diagnosis and prognostic evaluation of SS-MALT lymphoma.

METHODS

Sixteen patients with SS-MALT lymphoma were collected from 260 patients who were diagnosed with SS in Peking University School and Hospital of Stomatology from January 1997 to December 2016. Twelve patients with non-MALT lymphoma secondary to SS (non-SS-MALT lymphoma) in salivary gland were selected as controls. The clinical data of the patients were retrospectively reviewed and analyzed. All the patients were followed up until December 20, 2019. Hematoxylin-eosin staining, immunohistochemistry, polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH) techniques were used to observe the histologic characteristics and to detect the manifestations of light chain restrictive expression, immunoglobulin (Ig) gene clonal rearrangement, chromosome translocation and gene abnormality, so as to evaluate their values in pathological diagnosis and prognostic evaluation.

RESULTS

The malignant transformation rate of SS to MALT lymphoma was about 6.15%, ranged from 3 to 240 months, during which 2 patients died due to high-level deterioration. Microscopically, the acini of the glandular tissue were atrophied and destroyed. The tumor cells dominated by central cell-like lymphocytes grew diffusely, destroying the epithelial islands. All SS-MALT lymphoma cases were positive in CD20 and Pax5. Half of them had the Ki-67 proliferation index of 10% or less, and half greater than 10%. 93.75% cases expressed AE1/AE3 protein, which showed the residual glandular epithelium. All the tumor cells were negative in CD3ε, and the plasma cells were detected by CD138 antigen. The light chain restrictive expression of κ and λ was 37.5% in SS-MALT lymphoma group. The positive detection rates of immunoglobulin heavy chain (IgH)-FR1, IgH-FR2, IgH-FR3, immunoglobulin kappa chain (IgK)-A, and IgK-B in SS-MALT lymphoma group were 33.3%, 53.3%, 33.3%, 20.0%, and 26.7%, respectively, and 93.3% when together used with IgH and IgK. The positive rates of the MALT1, IGH and BCL6 genes with dual color break-apart probes were 36.4%, 27.3% and 27.3%, and the detection rate of chromosome translocation and gene abnormality by applying the three probes was 72.7%.

CONCLUSION

There are no specific histological characteristics and protein phenotypes in the histologic diagnosis of SS-MALT lymphoma in salivary gland. The combined application of histopathological manifestations, immunohistochemistry, PCR and FISH techniques helps the accurate pathologic diagnosis of the disease. Although SS-MALT lymphoma is considered as an indolent lymphoma with a relatively favorable prognosis, the regular return visit and long-term follow-up should be conducted to detect the clues of recurrence and advanced deterioration.

[Clinicopathological analysis of mucosa associated lymphoid tissue lymphoma secondary to Sjögren' s syndrome in salivary gland]

OBJECTIVE

To analyze the clinicopathological characteristics of mucosa associated lymphoid tissue (MALT) lymphoma secondary to Sjögren' s syndrome (SS) (SS-MALT lymphoma) in salivary gland and to explore the value of the combined application of histopathological morphology, protein expression and molecular phenotype in pathological diagnosis and prognostic evaluation of SS-MALT lymphoma.

METHODS

Sixteen patients with SS-MALT lymphoma were collected from 260 patients who were diagnosed with SS in Peking University School and Hospital of Stomatology from January 1997 to December 2016. Twelve patients with non-MALT lymphoma secondary to SS (non-SS-MALT lymphoma) in salivary gland were selected as controls. The clinical data of the patients were retrospectively reviewed and analyzed. All the patients were followed up until December 20, 2019. Hematoxylin-eosin staining, immunohistochemistry, polymerase chain reaction (PCR) and fluorescence in situ hybridization (FISH) techniques were used to observe the histologic characteristics and to detect the manifestations of light chain restrictive expression, immunoglobulin (Ig) gene clonal rearrangement, chromosome translocation and gene abnormality, so as to evaluate their values in pathological diagnosis and prognostic evaluation.

RESULTS

The malignant transformation rate of SS to MALT lymphoma was about 6.15%, ranged from 3 to 240 months, during which 2 patients died due to high-level deterioration. Microscopically, the acini of the glandular tissue were atrophied and destroyed. The tumor cells dominated by central cell-like lymphocytes grew diffusely, destroying the epithelial islands. All SS-MALT lymphoma cases were positive in CD20 and Pax5. Half of them had the Ki-67 proliferation index of 10% or less, and half greater than 10%. 93.75% cases expressed AE1/AE3 protein, which showed the residual glandular epithelium. All the tumor cells were negative in CD3ε, and the plasma cells were detected by CD138 antigen. The light chain restrictive expression of κ and λ was 37.5% in SS-MALT lymphoma group. The positive detection rates of immunoglobulin heavy chain (IgH)-FR1, IgH-FR2, IgH-FR3, immunoglobulin kappa chain (IgK)-A, and IgK-B in SS-MALT lymphoma group were 33.3%, 53.3%, 33.3%, 20.0%, and 26.7%, respectively, and 93.3% when together used with IgH and IgK. The positive rates of the MALT1, IGH and BCL6 genes with dual color break-apart probes were 36.4%, 27.3% and 27.3%, and the detection rate of chromosome translocation and gene abnormality by applying the three probes was 72.7%.

CONCLUSION

There are no specific histological characteristics and protein phenotypes in the histologic diagnosis of SS-MALT lymphoma in salivary gland. The combined application of histopathological manifestations, immunohistochemistry, PCR and FISH techniques helps the accurate pathologic diagnosis of the disease. Although SS-MALT lymphoma is considered as an indolent lymphoma with a relatively favorable prognosis, the regular return visit and long-term follow-up should be conducted to detect the clues of recurrence and advanced deterioration.