Mucosa-associated lymphoid tissue lymphoma of the salivary glands: MR imaging findings including diffusion-weighted imaging

Abstract

Purpose: The purpose of this study was to describe MR findings including diffusion-weighted (DW) imaging findings in patients with mucosa-associated lymphoid tissue (MALT) lymphoma of the salivary glands.

Materials and methods: Ten patients with histologically proven MALT lymphoma of the salivary glands were included. All patients underwent 1.5-T MR imaging, six of the ten underwent DW imaging, nine underwent CT, and eight (18)F-fluorodeoxyglucose (FDG) PET/CT. MR images were reviewed for numbers, locations, sizes, MR imaging characteristics, and apparent diffusion coefficients (ADCs). Calcium deposition and maximum standardized uptake values (SUVmax) were also assessed.

Results: Twenty-six tumors, ranging in number from 1 to 5 (mean, 2.6), were identified. Nine patients had tumors in the parotid glands and one in the submandibular glands. Tumors were found bilaterally in 7 patients and unilaterally in three. Tumors ranged in size from 0.6 to 5.5cm (mean, 1.8cm). Ten (38%) tumors had intratumoral cystic formations and 8 (31%) had ill-demarcated margins. DW images showed hyperintensity with extremely low ADCs (range, 0.48-0.82 [×10(-3)mm(2)/s]; mean, 0.64) for solid components of all 19 tumors in the 6 examined patients. Calcium deposition was found in one (4%) tumor on CT. SUVmax variously ranged from 1.3 to 17.7 (mean, 6.3).

Conclusion: Salivary gland MALT lymphomas were often found bilaterally and were occasionally accompanied by intratumoral cystic formations and ill-demarcated margins. DW imaging may play a supplementary role in the diagnosis of lymphoma, because it showed restricted water molecule diffusion, whereas PET/CT showed indeterminate findings.