t(3;14)(p14.1;q32)/FOXP1-IGH translocation in thyroid extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma)

Mucosa-associated lymphoid tissue lymphoma of the lacrimal gland: A case report and literature review

RATIONALE

The most common subtype of primary lymphoma of the ocular adnexa is the mucosa-associated lymphoid tissue (MALT) subtype. MALT lymphoma of the lacrimal gland is relatively rare among the lacrimal gland tumors, and the early clinical symptoms are atypical, which can easily lead to misdiagnosis and missed diagnosis. Here, we report a case of MALT lymphoma of the lacrimal gland and explore its clinical manifestations, pathological characteristics, management, and pathogenesis, with the aim of helping clinicians gain an in-depth understanding of ocular adnexal MALT lymphoma.

PATIENT CONCERNS

A 60-year-old man presented to our hospital with proptosis and diplopia. The right eye deviated and shifted toward the lower part of the nose.

DIAGNOSIS

Orbital enhanced magnetic resonance imaging suggested a mass with a maximum cross-section of 3.2 × 2.1 cm. T1 weighted image was isointense, and the enhancement was more uniform and obvious.

INTERVENTIONS

The right orbital mass was treated surgically, and the final pathology report was MALT lymphoma. After the pathological report was released, the patient was transferred to the hematology department for further diagnosis and no further treatment was given eventually.

OUTCOMES

Seven months later, the patient did not complain of discomfort. Whole-body positron emission tomography-computed tomography, superficial lymph node examination and orbital magnetic resonance imaging revealed no abnormal changes.

LESSONS

The clinical manifestations of MALT lymphoma are heterogeneous. Imaging examination is important for assessing the size of the tumor and its relationship with adjacent tissues. Postoperative pathological examination may provide further evidence for the evaluation of the patient's surgical efficacy and prognosis. Management of MALT lymphoma of the lacrimal gland requires a multidisciplinary approach involving ophthalmologists, hematologists, and radiotherapists.

Recent Advances in the Genetic of MALT Lymphomas

Simple Summary

Mucosa-associated lymphoid tissue (MALT) lymphoma is the most common subtype of marginal zone lymphomas. These B-cell neoplasms may arise from many organs and usually have an indolent behavior. Recurrent chromosomal translocations and cytogenetic alterations are well characterized, some of them being associated to specific sites. Through next-generation sequencing technologies, the mutational landscape of MALT lymphomas has been explored and available data to date show that there are considerable variations in the incidence and spectrum of mutations among MALT lymphoma of different sites. Interestingly, most of these mutations affect several common pathways and some of them are potentially targetable. Gene expression profile and epigenetic studies have also added new information, potentially useful for diagnosis and treatment. This article provides a comprehensive review of the genetic landscape in MALT lymphomas.

Abstract

Mucosa-associated lymphoid tissue (MALT) lymphomas are a diverse group of lymphoid neoplasms with B-cell origin, occurring in adult patients and usually having an indolent clinical behavior. These lymphomas may arise in different anatomic locations, sharing many clinicopathological characteristics, but also having substantial variances in the aetiology and genetic alterations. Chromosomal translocations are recurrent in MALT lymphomas with different prevalence among different sites, being the 4 most common: t(11;18)(q21;q21), t(1;14)(p22;q32), t(14;18)(q32;q21), and t(3;14)(p14.1;q32). Several chromosomal numerical abnormalities have also been described, but probably represent secondary genetic events. The mutational landscape of MALT lymphomas is wide, and the most frequent mutations are: TNFAIP3, CREBBP, KMT2C, TET2, SPEN, KMT2D, LRP1B, PRDM1, EP300, TNFRSF14, NOTCH1/NOTCH2, and B2M, but many other genes may be involved. Similar to chromosomal translocations, certain mutations are enriched in specific lymphoma types. In the same line, variation in immunoglobulin gene usage is recognized among MALT lymphoma of different anatomic locations. In the last decade, several studies have analyzed the role of microRNA, transcriptomics and epigenetic alterations, further improving our knowledge about the pathogenic mechanisms in MALT lymphoma development. All these advances open the possibility of targeted directed treatment and push forward the concept of precision medicine in MALT lymphomas.

Enhancing B-Cell Malignancies-On Repurposing Enhancer Activity towards Cancer

B-cell lymphomas and leukemias derive from B cells at various stages of maturation and are the 6th most common cancer-related cause of death. While the role of several oncogenes and tumor suppressors in the pathogenesis of B-cell neoplasms was established, recent research indicated the involvement of non-coding, regulatory sequences. Enhancers are DNA elements controlling gene expression in a cell type- and developmental stage-specific manner. They ensure proper differentiation and maturation of B cells, resulting in production of high affinity antibodies. However, the activity of enhancers can be redirected, setting B cells on the path towards cancer. In this review we discuss different mechanisms through which enhancers are exploited in malignant B cells, from the well-studied translocations juxtaposing oncogenes to immunoglobulin loci, through enhancer dysregulation by sequence variants and mutations, to enhancer hijacking by viruses. We also highlight the potential of therapeutic targeting of enhancers as a direction for future investigation.