A 17-year-old female, without medical history, presented with a 15-day history of diplopia, nasal obstruction, and left orbital pain, associated with fever and night sweats. The physical examination found a left exophthalmos and bilateral cervical lymphadenopathy. T2-weighted orbital magnetic resonance imaging showed a left soft-tissue mass slightly hyperintense compared to muscle involving intra- and extraconal space responsible for an exophthalmos, with an extension to the left ethmoid sinus and the left nasal fossa. Biopsy of the nasal mass and histopathologic examination objectified a high-grade DLBCL (CD20+, Bcl2+, CD3-, and CD5-, with a Ki-67 proliferation index of 95%). In addition, the cerebrospinal fluid analysis was consistent with a central nervous system (CNS) involvement.\nBaseline18F-FDG PET/CT revealed intense18F-FDG uptake throughout the bilaterally enlarged renal parenchyma, on the soft tissue in the left orbit extending into the left nasal cavity, and on cervical and abdominal lymph nodes. Peritoneal nodules with diffusely increased18F-FDG and multiple hypermetabolic bones foci, including humeri, ribs, and pelvis uptake were also noted []. After 4 cycles of dose-adjusted EPOCH-rituximab, the patient was referred for18F-FDG PET/CT for response evaluation. The18F-FDG PET/ CT showed a total regression of renal lesions suggesting good response to therapy [].
A 50-year-old Caucasian male with a history of alcohol and injection-drug abuse, chronic HCV infection, coronary heart disease, and idiopathic renal function impairment (creatinine clearance < 60 mL/min) for preceding four months attended in the emergency department with uremic symptomatology. He was dysphonic (O2 saturation, 85%) and hypertensive (blood pressure, 185/90 mmHg) and had prominent hepatosplenomegaly with mild peripheral edema; he had no palpable lymph nodes, skin rash, or other manifestations of systemic diseases. Laboratory analyses results were as follows: metabolic acidosis (pH, 7.123; and HCO3-, 8.6 mmol/L); mild hyperkalemia (K+, 5.7 mmol/L); hyperphosphatemia (PO43-, 10 mg/dL); hypoalbuminemia (albumin, 2.8g/L); anemia (hematocrit, 21.2%; and hemoglobin, 6.8 g/dL); thrombocytopenia (platelet, 72 × 10³/μL); lactate dehydrogenase,185 U/L; and severe renal failure (serum creatinine, 9.9 mg/dL; and urea, 199 mg/dL) with signs of glomerular involvement (urine red blood cells, 40 to 60/HPF; and 24-hour urine proteins, 3.06 g).\nThe clinical and laboratory findings on admission necessitated the immediate start of hemodialysis. Subsequent ultrasound studies revealed hepatosplenomegaly, two kidneys of normal size (right kidney, 11.7 cm; and left kidney, 11.5 cm), and parenchymal thickness (right kidney, 10 mm; and left kidney, 9.9 mm). There was no clinical or radiological sign of lymph nodes involvement. Further laboratory testing by immunological assay (ANA, anti-dsDNA, ASMA, AMA, C-ANCA, P-ANCA, and C3 complement levels) had negative results except for serum proteins electrophoresis, which showed a monoclonal gammopathy of IgM. At the same time, urine immunofixation revealed the presence of albumin, IgM, and kappa light chains, type I cryoglobulinemia, and low C4 complement levels. Considering the history of the patient and after excluding and treating all other causes of renal function deterioration, our diagnostic approach pointed towards an HCV-related renal offence in the context of cryoglobulinemia. However, the rapid decline of renal function and the absence of mixed cryoglobulinemia suggested performing the renal biopsy. While the histopathological examination of the specimen was consistent with the initial suspicion, indicating MPGN (), the immunofluorescence study revealed two unusual findings: dominant monoclonal IgMκ deposits in glomerular basement membrane and infiltration of the interstitium by abundant strongly IgM-positive lymphoid cells (). The presence of CD20 cell marker was distinctive while CD5 was absent. According to these findings, a bone marrow biopsy was performed. The histopathological examination revealed plasmacytic differentiation of small B cells and the immunophenotyping results were positive for CD20 and negative for CD5. These findings were consistent with SMZL. The patient became hemodialysis dependent and received no treatment for the lymphoproliferative disease and was monitored regularly for possible transformation to a high-differentiated lymphoma.