Dear Editor, A 47-year-old man was hospitalized in November 2006 for hyperthermia into the Division of Tropical Infectious Diseases. The patient had been diagnosed with HIV infection 14 years before and was in antiretroviral therapy since 9 years; his CD4-positive cells ranged between 300 and 650 cells per microliter and viral load remained less than <50 copies per microliter with didanosine, lamivudine, and atazanavir. Since the diagnosis, he did not show any relevant HIV-related clinical event. At admission, the physical exam revealed organic decay, weight loss, multiple small superficial adenopathies and marked splenomegaly (spleen palpable in left iliac region). The patient was initially treated with antipyretics, hydration, and continued antiretroviral therapy. The blood cell count showed white blood cells 3,840 per microliter (lymphocytes 66%, absolute count 2,534 per microliter), platelets 1,233,000 per microliter, and hemoglobin 10.3 g/dl. The biochemistry showed lactate dehydrogenase 818 mU/ml, β2-microglobulin 4,100 μg/l, alkaline phosphatase 1,093 U/l, erythrocyte sedimentation rate 17, C-reactive protein 0.6 mg/dl, total protein 6.1 g/dl, αfraction 8%, gamma globulin 10%; microbiological analyses of blood and urine were negative as well as hepatitis C virus (HCV) serology; hepatitis B virus (HBV) serology showed HbsAg, HBsAb, and HbcAb positive. Computed tomography (CT) scan documented splenomegaly (diameter 30×22 cm) without any focal lesion and an accessory spleen (diameters 10×4 cm), multiple adenopathies at splenic hilus and along the spleen vessels, ectasia of the spleen–portal system, and little ascites in the pelvic cavity. Bone marrow biopsy revealed a nodular lymphoid infiltration suspicious for lymphoma involvement. In December 2006, the patient underwent splenectomy. At laparotomy, spleen appeared occupying the whole left hemiabdomen and displacing the stomach and bowel with an accessory spleen (diameter 10 cm) at inferior pole of spleen (Fig. 1a); at the splenic hilus, multiple confluent lymph nodes surrounded splenic artery and vein and the tail of the pancreas. Spleen, accessory spleen, and hilus lymph nodes were removed; distal pancreasectomy and a wedge-shaped biopsy of third hepatic segment were also performed. The resected spleen (38×22×8 cm) weighted 4,400 g and showed, on the cut section, a multimicronodular pattern. Histologically, the micronodular lymphoma infiltrate involved both the white pulp and the red one (partially). Nodules consisted of a prevalent smallto medium-sized lymphoid population with round nuclei and moderate clear cytoplasm; a minority (<10%) of large blastic cells were present. The lymphoma cells were positive for CD20+, CD79a+, bcl2+, DBA44+/−; immunostainings for CD5, CD10, cyclin D1, bcl6, CD23, CD25, TRAP, IgM, and IgD were negative. The growth fraction (evaluated by means of MiB1/Ki67) was 10%. Immunohistochemistry and in situ hybridization search for Epstein-Barr virus (EBV) was negative. A diagnosis of Ann Hematol (2009) 88:379–381 DOI 10.1007/s00277-008-0587-4