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 eight18 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 5.5 cm (mean, 1.8 cm). 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 mm2 /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.