A case of a pulmonary mucosa-associated lymphoid tissue lymphoma with chromosomal aberration (49, XX, +3, +i(6)(p10), +mar).

We report a case of a primary pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma with chromosomal aberration (49, XX, +3, +i(6)(p10), +mar). A 59-year-old woman was referred to our hospital for an abnormal chest shadow detected during a routine health check-up in 2014. Chest computed tomography revealed a 3.2- × 2.3- × 2.0-cm tumour shadow in the right middle lobe. Transbronchial biopsy did not result in the diagnosis of the tumour. Accordingly, as the tumour could have been malignant, right middle lobectomy was performed via video-assisted thoracic surgery. On the basis of the results of immunohistochemical staining and gene analysis, the tumour was diagnosed as a primary pulmonary MALT lymphoma with chromosomal aberration (49, XX, +3, +i(6)(p10), +mar).

Introduction

Mucosa‐associated lymphoid tissue (MALT) lymphoma is categorized as extranodal marginal zone B‐cell lymphoma of the MALT type according to the World Health Organization (WHO) classification of malignant lymphomas. Pulmonary MALT lymphoma is categorized as an indolent tumour, indicating that it is a low‐grade, malignant lymphoma.

Although MALT lymphoma with chromosomal aberration has been well reported, pulmonary MALT lymphoma with chromosomal aberrations is not well documented in the literature. Therefore, herein, we report our experience of a patient with MALT lymphoma with chromosomal aberration (49, XX, +3, +i(6)(p10), +mar).

Case Report

A 59‐year‐old woman was referred to our hospital owing to pulmonary opacity on radiography. Chest radiography revealed a tumour shadow in the right lung field (Fig. 1A). Chest computed tomography revealed a part solid type tumour in the right middle lobe (Fig. 1B). The patient did not have lymphadenopathy or pleural effusion. Transbronchial biopsy did not result in the diagnosis of the tumour. Hence, as the tumour could have been malignant, the patient underwent right middle lobectomy via video‐assisted thoracic surgery under general anaesthesia. On the basis of the results of histopathological examination and gene analysis, the tumour was diagnosed as a primary pulmonary MALT tumour with chromosomal aberration (49, XX, +3, +i(6)(p10), +mar) (Fig. 2). A Ki67 score (MIB‐1 index) of the tumour was 5.7%. Owing to the localized nature of the pulmonary MALT lymphoma, the patient did not receive chemotherapy after the right middle lobectomy. The patient had an uneventful course without any evidence of recurrence for five years.

Figure 1

(A) Chest radiography scan showing a tumour shadow in the right middle lung field. (B) Chest computed tomography scan showing a tumour measuring 3.2 × 2.3 cm in the right middle lobe.

Figure 2

The G‐banding karyotype was 49, XX, +3, +i(6)(p10), +mar.

Discussion

The following four specific chromosomal aberrations have been reported in MALT lymphoma: (1) t(11;18)(q21;q21)/API2‐MALT1, (2) t(1;14)(p22;q32)/BCL10‐IGH, (3) t(14;18)(q32;q21)/IGH‐MALT1, and (4) t(3;14)(p14;q32)/FOXP1‐IGH 1, 2. Among these aberrations, t(11;18)(q21;q21)/API2‐MALT1 is the most frequent in pulmonary MALT lymphoma. In addition, aneuploidy is a common chromosomal aberration in MALT lymphoma, which is trisomy 3, 7, 11, 12, 17, 18, and/or 21 1, 3. In addition to the above‐mentioned chromosomal aberrations, rare variant translocations have been reported in MALT lymphomas. For example, Chuang et al. reported a pulmonary MALT lymphoma with t(1;2)(p22;p12)/IGK‐BCL10 4. Penas et al. reported a gastric MALT lymphoma with t(6;18;11) (q24;q21;q21) as well as a pulmonary MALT lymphoma with t(11;14;18) (q21;q32; q21) 5. On the basis of these findings, MALT lymphoma can have a variety of chromosomal aberrations that are yet undiscovered.

In the current study, the lymphoma cells had a 49, XX, +3, +i(6)(p10), +mar karyotype. Although aberrations in chromosome 6 in MALT lymphoma have been reported, they have not been reported in pulmonary MALT lymphoma. Ott et al. reported that deletions in the long arm of chromosome 6 (6q) were frequent in MALT lymphoma and involved chromosome 14q32 1. To the best of our knowledge, this is the first case of chromosomal aberration (49, XX, +3, +i(6)(p10), +mar), especially the aberration in chromosome 6, in pulmonary MALT lymphoma. Further studies are required to elucidate the mechanism of chromosomal aberration in pulmonary MALT lymphoma.

Disclosure Statement

Appropriate written informed consent was obtained for publication of this case report and accompanying images.