Primary Pancreatic Lymphoma: Endosonography-Guided Tissue Acquisition Diagnosis

Abstract

Primary pancreatic lymphoma is a rare type of cancer, that accounts for 0.1-0.5% of lymphomas and about 0.2% of all primary pancreatic tumors. Diffuse Large B-cell Lymphoma is the most common subtype. The diagnosis is possible if the lymphoma is located in the pancreas, but the differential diagnosis with pancreatic ductal adenocarcinoma is difficult. The diagnostic accuracy of endosonography-guided fine needle aspiration is inadequate, and thus it is common to diagnose these masses only after surgical resection. The endosonography-guided tissue acquisition allows greater accuracy in the pancreatic masses, as it determines optimal access to histological analysis using tissue in paraffin blocks for complementary immunohistochemical, and molecular tests. Thus, this elaborate diagnostic environment allows the adoption of appropriate treatment strategies for patients with this condition. The authors describe four cases of primary pancreatic lymphoma indicated for surgical resection due to suspected pancreatic cancer, with the diagnosis of Diffuse Large B-cell Lymphoma obtained by endosonography-guided tissue acquisition, changing the therapeutic strategy through the adoption of adequate chemotherapy treatment with good progress.

Keywords: diagnosis; endoscopic ultrasound; fine needle biopsy; imunohistochemistry; lymphoma pancreatic.

Figure 1. Endosonographic and histology images

(a) Hypoechoic, heterogeneous solid nodule with imprecise borders (yellow arrows) and peripheral lymph nodes. (b) Node (yellow arrows) measuring 38 x 29 mm and lymph nodes of 12 x 12 mm. (c) Doppler (+) of vascular structure encompassed by the mass (red arrow). (d) Elastography showing a stiff pancreatic nodule. (e) Histology – microscopic imaging of Diffuse Large B-cells Lymphoma (red arrow).

Figure 2. Endoscopic and immunohistochemistry examination images

(a) Endoscopic Ultrasound equipment in front of the duodenal papilla, with the metallic stent exiting the duodenal papilla (red arrows). (b and c) Endoscopic Ultrasound imaging:  metallic stent inside the common bile duct (red arrows); hypoechoic and heterogeneous area (34 x 22 mm) of imprecise limits (yellow arrows) and Doppler (+). (d) Lymph node measuring 12 x 11 mm (yellow arrow), with the puncture needle (red arrow) inside. (e) Diffuse Large B-cell Lymphoma (Hematoxilin and Eosin – 200X) e (f) Immunohistochemistry with CD 20 (+).

Figure 3. Endoscopic ultrasound imaging

(a) hypoechoic and heterogeneous area with poorly defined limits (yellow arrows). (b) solid-cystic, irregular lesion located at the ill-defined body/tail transition, measuring 45 x 34 mm (yellow arrows). (c) Solid-cystic lesion without Doppler signal affecting the splenic artery (yellow arrows). (d) Insertion of the puncture needle for tissue acquisition (red arrow), within the limits of the lesion (yellow arrow).

Figure 4. Immunohistochemistry examination images

(a) Tissue acquisition obtained during Endoscopic Ultrasound with the ProCore 20G needle. The specimen is 0.28 mm wide and 1.7 mm long. (b) Hematoxylin and Eosin – 200x magnification with large amounts of material. (c) Lymphoma with areas of sclerosis and vascular invasion (yellow arrows). (d) The Immunohistochemical profile determines the histogenesis of the lymphoma and subclassifies it into Diffuse Large B-cell Lymphoma of non-germinal center origin (see Table 2)

Figure 5. Endoscopic ultrasound imaging

The image shows a solid-cystic lesion (red arrows), measuring 56 x 50 mm in the largest axes, located in the body of the pancreas.