Malt lymphoma of the lacrimal gland in a patient with Sjogren syndrome.

Clinical History

A 73-year old male with known Sjogren’s syndrome (S.S) presented as an outpatient at the rheumatology department of our hospital with left upper eyelid edema and ptosis. Clinical examination revealed a unilateral enlargement of the left lacrimal gland.

Imaging Findings

MRI of the orbits confirmed the enlargement of the left lacrimal gland which appeared with an increased signal (arrow) in T2W STIR images (Fig.1). Homogeneous enhancement (curved arrow) was evident after intravenous contrast (GD-DTPA) injection in T1W SPIR images(Fig.2). The differential diagnosis at this point included the presence of a pseudotumor, bacterial or viral dacryadenitis, tuberculosis, sarcoidosis and lymphoma. The purified protein derivative skin test and the chest radiograph revealed no abnormalities. Repeated blood and urine cultures were negative. Serological tests for hepatitis B, C, Epstein Barr, cytomegalovirus and human immunodeficiency viruses 1 and 2 were also negative.
Biopsy of the lacrimal gland and the ipsilateral superior rectus muscle revealed invasion by extranodal marginal zone mucosa-associated lymphoid tissue (MALT) lymphoma expressing monoclonal K light chain and CD20 positive cells.

Discussion

One of the most serious complications of S.S is the development of malignant lymphoma. The incidence of lymphoma among patients with S.S syndrome is approximately 44 times higher compared to the general healthy population. In published reports, MALT lymphomas account for 46-56% of the malignant lymphomas seen in patients with S.S. (1-3). Tomani H. et al described two patients with primary S.S and enlargement of both lacrimal glands. Histopathologic confirmation was obtained in both patients. Of the four lacrimal glands, one was finally diagnosed with lymphoepithelial disease, two with pseudolymphoma and one with MALT lymphoma(4). Unilateral development of MALT lymphoma in the lacrimal gland of patients suffering from S.S, as in this case, is uncommon. Therefore, one should always take into consideration the possibility of MALT lymphoma when establishing the differential diagnosis in cases of unilateral lacrimal gland enlargement in patients with S.S. Furthermore DWI MR imaging may help to differentiate orbital lymphomas from other lesions. DWI measures the diffusion of water molecules in biologic tissues; diffusion within the tumor is considered a surrogate marker of tumor cellularity because intact cells constitute a barrier to water diffusion. Because CNS or orbital lymphomas are highly cellular tumors, water diffusion is often restricted, making them appear hyperintense on DWI and hypointense on ADC maps. So DWI is a useful imaging tool in differential diagnosis before biopsy(5).

Differential Diagnosis List

Final Diagnosis

Malt lymphoma of the lacrimal gland.

URL:	https://www.eurorad.org/case/12884
DOI:	10.1594/EURORAD/CASE.12884
ISSN:	1563-4086