Imaging findings of primary splenic lymphoma: a review of 17 cases in which diagnosis was made at splenectomy

Abstract

Purpose: This study sought to characterize the imaging features of primary splenic lymphoma (PSL).

Materials and methods: Pathological and imaging data from 17 patients with primary splenic lymphoma initially diagnosed at splenectomy were retrospectively analyzed. Pretreatment computed tomography (CT) imaging was available for 16 patients, and magnetic resonance imaging (MRI) data were available for 4 patients. Splenic lymphoma imaging data were categorized based on the gross pathological presentation in the following manner: type 1, homogeneous enlargement; type 2, miliary nodules; type 3, multifocal masses of varying size; and type 4, solitary large mass.

Results: Of the 17 patients with PSL, 16 cases were non-Hodgkin lymphoma, and of these, 9 cases were diffuse large B cell lymphomas (DLBCL) and 4 cases were splenic marginal zone B-cell lymphoma (SMZL). Imaging showed the following types of PSL presentation: 1 case of type 1, 0 cases of type 2, 4 cases of type 3, and 12 cases of type 4. There was evidence of necrosis in 12 cases (70.6%), and there was evidence of mild enhancement in enhanced CT in 14 cases and in enhanced MRI in 3 cases. Prior to surgery, PSL was considered possible in 8 patients.

Conclusion: The most frequent histological subtype was DLBCL, followed by SMZL. In both CT and MRI, PSL generally presents as a solitary mass or masses rather than as splenomegaly. In addition, necrosis and mild enhancement are commonly observed, and splenectomy may be required to confirm the diagnosis.

Figure 1. The case of a 66-year-old male patient who had experienced left upper quadrant pain for 1 month is presented.

This patient was diagnosed with PSL at splenectomy. (A) A CT plain scan showed a solitary focal mass with faint hypodensity in the spleen. Contrast-enhanced CT showed mild enhancement of the mass in the (B) arterial phase, (C) the portal phase, and (D) the coronal portal phase. The central hypodensity within the mass represents necrosis. MRI plain scans showed a hypointense signal in (E) T₁WI and a hyperintense signal in (F) T₂WI and (G) DWI. Enhanced MRI findings for the (H) arterial phase, (I) the portal phase, (J) the delayed phase and (K) the coronal delayed phase demonstrated mild enhancement. (L) The histopathology of the splenic lesion was suggestive of diffuse large B-cell lymphoma (DLBCL) (H&E, 100×).