Primary pancreatic lymphoma: two case reports and a literature review

Abstract

Primary pancreatic lymphoma (PPL) is an extremely rare disease, with only a few cases reported in the literature. Clinical manifestations of PPL are often nonspecific and may mimic other pancreatic diseases. Because of the limited experience of PPL, clinicopathological features, differential diagnosis, optimal therapy, and outcomes are not well defined. We described two cases diagnosed as PPL and confirmed by histological examination and immunohistochemical analysis. Case 1 was a young man with obstructive jaundice and upper abdominal malaise mimicking a pancreatic adenocarcinoma. A computed tomography (CT) scan revealed a diffuse heterogeneous mass in the head of the pancreas along with dilated bile ducts, no dilated pancreatic duct, no liver or splenic involvement, or evident retroperitoneal adenopathies. The patient underwent a pancreatico-duodenectomy, and the postoperative histopathology confirmed diffuse large B-cell non-Hodgkin lymphoma. Postoperatively, he received six courses of the CHOP regimen (cyclophosphamide, doxorubicin, vincristine, and prednisolone). Case 2 was an older man with left flank pain. A CT confirmed a mass with irregular margins at the tail of the pancreas and the hilum of the spleen. The mass was heterogeneous, with no clear boundary between lesions, spleen, stomach, and pancreas, with nearby blood vessels wrapped around it, and multiple enlarged lymph nodes in the abdominal cavity. A CT-guided biopsy was performed. The immunohistological findings of the specimen revealed a diffuse large B-cell lymphoma. The size of the tumor was significantly reduced after four cycles of the CHOP chemotherapy regimen. These two cases were different in clinical manifestation, location, and treatment. We reviewed the literature and discussed the clinicopathological features, differential diagnosis, optimal therapy, and outcomes of this neoplasm.

Keywords: diagnosis; diffuse large B-cell lymphoma; pancreatic malignant tumor; primary pancreatic lymphoma; survival and prognosis; treatment policy.

Figure 1

Abdominal CT findings. A CT scan showing diffuse hypodense enlargement of the pancreatic head (arrow). Notes: (A–B) unenhanced and (C–D) arterial phase. Abbreviation: CT, computed tomography.

Figure 2

A gross pathological examination revealed a 3.0 × 4.0 cm multiseptated mass in the pancreatic head (arrow). The cut surface of the tumor was yellowish (arrow).

Figure 3

Histopathology showed small tumor cells without cell adhesion or tissue structure proliferation (A), and HE immunochemical staining was positive for B-cell markers CD20 and CD79a (B, C), compatible with the diagnosis of diffuse large B-cell non-Hodgkin lymphoma. HE immunochemical staining confirmed a proliferative index of over 50–60% (D). (A–C ×400; D ×200). Abbreviation: HE, hematoxylin and eosin.

Figure 4

A PET-CT did not detect any signs of disease recurrence after 16 months. Notes: A and B represent different planes on PET-CT. Abbreviations: R, right; L, left; PET-CT, positron emission tomography-computed tomography.

Figure 5

(A, B) A CT scan showing diffuse hypodense enlargement of the pancreatic tail (arrow).

Figure 6

Pathological findings. (A) HE shows irregularly-shaped, atypical lymphocyte infiltration (×40). (B) CD20 positive atypical lymphocytic cells (×400). (C) A high Ki-67 proliferation index (80%; ×200). Abbreviation: HE, hematoxylin and eosin.

Figure 7

Lesions were significantly reduced after 2 cycles of CHOP chemotherapy regimen (A, B). After 4 cycles of CHOP chemotherapy regimen (C, D).