Cryoglobulins are immunoglobulins that precipitate at temperatures below 37 °C and dissolve upon reheating. They can induce small-vessel vasculitis with renal involvement. Cryoglobulinemic glomerulonephritis is a rare manifestation that occurs in patients with monoclonal gammopathy, specifically Waldenström\'s macroglobulinemia. We present the case of a 52-year-old patient with a history of cutaneous vasculitis and hypothyroidism, who presented with generalized edema, moderate anemia, hypercholesterolemia, nephrotic range proteinuria of 12.69 g/day, microhematuria, arterial hypertension, and hypocomplementemia via the classical pathway, without acute kidney injury and with negative serological studies and positive cryoglobulins in the second determination. Serum and urine protein electrophoresis and immunofixation studies showed a monoclonal band of IgM and kappa light chain. Renal biopsy was consistent with cryoglobulinemic glomerulonephritis. In the context of dysproteinemia and cryoglobulinemic glomerulonephritis, bone-marrow aspiration and biopsy were performed, leading to the diagnosis of Waldenström\'s macroglobulinemia. Monoclonal gammopathies have been described in association with type I cryoglobulinemias. This described association is uncommon, which is why we present this case, along with a review of the literature.

Intraparenchymal lung abscess development associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a rare complication, with only half a dozen primary cases having been reported in the literature. We present the case of a patient with Waldenström\'s macroglobulinemia who developed a lung abscess subsequent to a primary SARS-CoV-2 infection. We present a 63-year-old male patient with SARS-CoV-2 infection and a history of Waldenström\'s macroglobulinemia who developed a cavitating intraparenchymal lung abscess with an air-fluid level in his right lower lobe two weeks following admission to hospital. The patient became septic and developed acute respiratory failure requiring mechanical ventilation and intensive care. He was managed with broad-spectrum antibiotic therapy and aspiration drainage, but unfortunately due to his severe clinical condition died 20 days after his initial admission. The development of a lung abscess in patients with COVID-19, although rare, can be quite compromising and even prove fatal, especially in immunocompromised patients. Clinicians should be aware of this potential complication.

BACKGROUND: The co-existence of Waldenström\'s macroglobulinemia (WM) with internodal marginal zone lymphoma (INMZL) is rare and often associated with poor prognosis.
METHODS: We present a Chinese female patient who developed secondary light chain amyloidosis due to WM and INMZL and provides opinions on its systemic treatment. A 65-year-old woman was diagnosed with WM 6 years ago and received Bruton tyrosine kinase inhibitor monotherapy for two years. Her INMZL was confirmed due to left cervical lymphadenopathy. The patient presented with oedema in both lower limbs one year ago, and was diagnosed with secondary light chain amyloidosis. Treatment with the BC regimen (rituximab 375 mg/m2 monthly for 6-8 courses, and bendamustine 90 mg/m2 per day × 2, monthly for six courses) was initiated, but not tolerated due to toxic side effects. Bortezomib-based therapy was given for two months, including bortezomib, dexamethasone, and zanubrutinb. Oedema in both lower limbs was relieved and treatment efficacy was evaluated as partial remission.
CONCLUSIONS: A detailed clinical evaluation and active identification of the aetiology are recommended to avoid missed diagnosis and misdiagnosis.

Late onset neutropenia (LON) related to rituximab or rituximab plus chemotherapy is defined as an unexplained absolute neutrophil count of ≤1.5 × 109/L starting at least four weeks after the last rituximab administration. LON is infrequent and its pathophysiology remains unknown. There are no guidelines or consensus strategies for the optimal management of patients developing LON. The majority of the patients recover promptly with no specific treatment and only some cases need to be managed with granulocytic colony stimulating factor (G-CSF), usually with a rapid response. Here, we describe a 69-year-old patient with Waldenström\'s macroglobulinemia who presented a septic event in the context of severe LON after rituximab plus bendamustine. The diagnosed of agranulocytosis was established by bone marrow examination. Interestingly, anti-neutrophil antibodies bound to the patient\'s granulocytes were found suggesting an autoimmune mechanism. The patient did not respond to G-CSF but achieved a rapid response after high doses of intravenous immunoglobulins with full white blood cell recovery.

BACKGROUND: Waldenström\'s macroglobulinemia is a rare B-cell lymphoma. The gold standard treatment for Waldenström\'s macroglobulinemia is an anti-CD20 antibody (rituximab) in combination with alkylating agents and dexamethasone. Treatment targeting the B-cell receptor such as ibrutinib (but not idelalisib) is currently approved for treatment of patients with relapsed or refractory Waldenström\'s macroglobulinemia.
METHODS: We report a case of a 71-year-old white French man with Waldenström\'s macroglobulinemia who presented with acute renal failure and hyperviscosity syndrome. His Waldenström\'s macroglobulinemia was refractory to first-line treatment with rituximab, cyclophosphamide, and dexamethasone. Because of his hemorrhagic syndrome and medical history of recent myocardial infarction, we decided to treat him with idelalisib 150 mg twice daily instead of ibrutinib. We observed a very quick improvement in the patient\'s clinical status without need for dose adjustment.
CONCLUSIONS: Our patient\'s case provides the first evidence, to the best of our knowledge, that idelalisib may be an efficient treatment option for patients with Waldenström\'s macroglobulinemia complicated by anuric renal failure and in whom ibrutinib is contraindicated.