Abstract:

Objective　To study the anatomy and imaging features of Oropharyngeal in non-Hondgkin's lymphoma (NHL) by PET/CT and MRI to improve the diagnosis of NHL.　Methods　The 30 cases diagnosed as NHL through clinical and pathologic tests were retrospectively analyzed in regard to appearance, location, signal, enhanced features, SUVmax and metastasis by PET/CT and MRI.　Results　Of 30 cases, 21 cases of Oropharyngeal NHL originated from B-cell（76.7%）, 5 cases from T-cell （16.7%），and four cases from NK/T-cell （6.7%）. The tonsil was the most vulnerable site （n=19）.  Three types in appearances of lesions could be observed. Specifically,  10 cases were mass type, 8 cases diffusion type, 12 cases mixed type. On plain CT scans, the lesions manifested as iso-or slightly hyper-density masses, and showed homogeneous and even enhancement after contrast injection. On T1WI, the lesions were isointense or slightly hypointense signal while on T2WI those were isointense or slight hyperintese signa1. SUVmax of primary tumors was increased significantly(n=25). All cases showed narrowing of the parapharyngeal space, but the high signal of the fat was showed on MRI; Coincidently, mucosae of pharynx oralis was continuous. Cervical lymph nodes were involved in 25 cases, and the density was homogeneous in 22 cases, a few metastases (3 cases) appeared as necrosis or cyst.　Conclusion　Oropharyngeal NHL have some characteristic imaging features of the position, SUVmax, shape and range of lymphoma of Oropharyngeal and metastases in lymph nodes and infilatration changes of its surrounding tissue. PET/CT and MRI are of crucial importance in the diagnosis and treatment of oropharyngeal NHL.

Key words: Oropharynx, Lymphoma, Anatomy, PET/CT, Magnetic resonance imaging