CT imaging of primary pancreatic lymphoma: experience from three referral centres for pancreatic diseases

Abstract

PurposeTo describe CT characteristics of primary pancreatic lymphoma (PPL), a rare disease with features in common with adenocarcinoma.Materials and methodsFourteen patients were enrolled. CT: unenhanced scan, contrast-enhanced pancreatic and venous phases. Image analysis: tumour location; peri-pancreatic vessel encasement; necrosis; enlarged lymph nodes; fat stranding; enlarged bile duct and pancreatic duct; neoplasm longest dimension, volume and density.ResultsHistopathological diagnoses: follicular non-Hodgkin lymphoma (5/14), diffuse large B-cell lymphoma (6/14) and high-grade B-cell lymphoma not otherwise specified (3/14). Six of 14 PPLs were located in the pancreatic head and 7/14 in the body-tail; 1/14 involved the whole gland. In 5/14 cases the superior mesenteric artery and vein were encased; splenic vein and artery encasement was depicted in 2 PPLs. Necrosis was present in 2/14. Enlarged retroperitoneal lymph nodes were found in 11 cases and fat stranding in all patients. The bile duct was dilated in six cases and the pancreatic duct in five. Mean neoplasm longest diameter and volume were 8.05 cm and 210.8 cm3. Mean tumour attenuation values were 39.1 HU at baseline, 60.6 HU in the pancreatic phase and 71.4 HU in the venous phase.ConclusionsPPL presents as a large mass lesion with delayed homogeneous enhancement; peri-pancreatic fat stranding and vessel encasement are present, without vascular infiltration. Pancreatic duct dilatation is rare.Key points• Primary pancreatic lymphoma (PPL) is a rare haematological disease • PPL presents imaging features in common with pancreatic carcinoma but also some distinctive findings • The majority of PPLs are large lesions with delayed homogeneous enhancement• Peri-pancreatic fat stranding and vessel encasement are common in PPL• Vascular infiltration and pancreatic duct dilatation are rare in PPL

Primary Pancreatic Diffuse Large B-Cell Lymphoma Involving the Stomach

“…cumscribed tumoral form, and 2) a diffuse enlargement infiltrating or replacing most of the pancreatic gland. As in our patient, a bulky localized tumor in the pancreatic head without significant main pancreatic duct dilatation and with significant lymphadenopathy below the level of the renal veins, suggestive of PPL, is observed by CT[11]. Endoscopic ultrasound has also been widely used to evaluate pancreatic masses and surrounding structures; it is more sensitive than CT for detection of small lesions[1].…”

“…There is no specific clinical manifestation suggestive of PPL Contrast-enhanced CT is the imaging modality of choice for evaluation of a pancreatic mass [11]. PPL can be divided into two typical morphological groups on CT: 1) a localized, well-cir- The treatment strategy for PPL consists of surgery, radiotherapy, chemotherapy, or a combination thereof [12].…”

“…Furthermore, tissue sampling can be performed by endoscopic ultrasound-guided fine-needle aspiration or by biopsy with high sensitivity and specificity[4]. Positron emission tomography is helpful in the staging of lymphoma, differentiation of malignant from benign lesions, and evaluation of therapeutic response[11]. Although radiological examinations can provide support in the diagnosis of PPL, they are unable to distinguish between PPL and other pancreatic lesions.…”

Primary Pancreatic Lymphoma: Recommendations for Diagnosis and Management

“…At color-Doppler evaluation major vessels can be surrounded by pathological tissue, but always patent (contrary to other solid neoplasms like adenocarcinoma). 110 , 114 When a pancreatic disease is identified by US a second line radiological examination, usually CT, is mandatory.…”

“…Involved parenchyma shows lower signal intensity on T1-weighted images and higher signal on T2-weighetd images compared to healthy pancreas; diffusion-weighted sequences present very high sensitivity to depict lymphomatous tissue and lymph nodes. 114 PET-CT is indicated to assess the metabolic activity of the primary neoplasm and to depict involved lymph nodes in the whole body. 98 …”