Rare Causes of Isolated and Progressive Splenic Lesions: Challenges in Differential Diagnosis, Evaluation, and Treatment of Primary Splenic Lymphomas

Abstract

The spleen is among the most common extranodal sites for Hodgkin and non-Hodgkin lymphomas (NHLs); however, among lymphomas arising from the spleen, primary splenic lymphomas (PSLs) are rare. The group of PSLs includes primary splenic diffuse large B-cell lymphoma (PS-DLBCL), splenic red pulp small B-cell lymphoma, splenic marginal zone lymphoma (SMZL), and a splenic hairy cell leukemia variant. Delineating between the PSL variants can be challenging, especially as fine-needle aspirate and core needle biopsy of the spleen are not routinely offered at most medical centers. Herein, we describe the clinical course of 2 representative patients who presented with non-specific gastrointestinal symptoms, the first who was diagnosed with PS-DLBCL and the second who was diagnosed with SMZL. We review and contrast the clinical presentations, imaging techniques, and laboratory findings of these discrete lymphoma variants and offer strategies on how to delineate between these varied splenic processes. We also examine the use of splenectomy and splenic needle biopsy as diagnostics and, in the case of splenectomy, a therapeutic tool. Finally, we also briefly review treatment options for these varied lymphoma sub-types while acknowledging that randomized trials to guide best practices for PSLs are lacking.

Keywords: Splenic lymphoma; evaluation; splenic nodules; treatment.

Figure 1.

Multi-phase magnetic resonance imaging (MRI) at 1, 5, and 10 minutes (A, B, and C, respectively) showing a multi-lobulated, non-vascular 3.5 × 4.9 cm progressive heterogeneous enhancement in the spleen. (D) A section of the resected spleen showing the primary splenic diffuse large B-cell lymphoma lesion.

Figure 2.

(A) Hematoxylin and eosin (H&E) staining of the solid splenic lesion showing large highly atypical lymphoid cells, including a few very large multi-nucleate and anaplastic cells. Immunohistochemical staining of the sample was positive for CD20 and BCL6 (B and C, respectively). The Ki-67 stain (D) indicated a principally 100% proliferation index in B-cells.

Figure 3.

Peripheral blood smear showing lymphocytosis with (A) small mature lymphocytes and (B) occasional lymphocytes with cytoplasmic projections (arrow). (C) Whole body ¹⁸fluorodeoxyglucose positron emission tomography/computerized tomography (¹⁸FDG-PET-CT) scout film showing splenomegaly and diffuse increased uptake in the spleen. (D) Follow-up ¹⁸FDG-PET-CT showing complete metabolic response.