Solitary intraventricular Hodgkin lymphoma post-transplant lymphoproliferative disease (HL-PTLD): Case report.

Lymphomas affecting the central nervous system (CNS), both primarily and secondarily, are uncommon malignancies. Immunosuppressed states, including iatrogenic immunosuppression following organ transplantation, are the most significant risk factors for developing primary CNS lymphoma (PCNSL). Post-transplant lymphoproliferative disease (PTLD) is a well described complication following bone marrow or solid organ transplantation. PTLD is usually a systemic disease with occasional CNS involvement. The incidence of CNS involvement in PTLD is low, and the majority of these cases tend to be PCNSL. Hodgkin lymphoma PTLD (HL-PTLD) constitutes only a very small percentage of PTLD. We report a rare case of a primary intraventricular CNS classical HL-PTLD in a male patient, 18 years following renal transplantation. The location allowed for safe neurosurgical intervention which resolved the symptom of elevated intracranial pressure and allowed for induction of a Rituximab-based chemotherapy regimen. Both the ventricular location of the PTLD and Hodgkin Lymphoma PTLD are themselves individually quite rare and have not previously been reported together. The unique location allowed safe neurosurgical intervention which quickly resolved the symptom of elevated intracranial pressure and allowed for induction of a Rituximab-based chemotherapy regimen.

Glioblastoma in a patient with tuberous sclerosis.

Tuberous sclerosis complex (TSC) is a multisystem, autosomal dominant disorder with a wide clinical spectrum. The most common brain tumor associated with TSC is the low grade subependymal giant cell astrocytoma. Reports of high grade primary brain tumors in patients with TSC are rare. TSC1/2 mutation has been identified in glioblastoma (GBM) even though it probably does not increase the overall risk for GBM in patients with TSC. We present a 58-year-old patient with known TSC, admitted for new neurological symptoms, diagnosed with a large heterogeneous tumor involving most of the corpus callosum. Stereotactic needle brain biopsy confirmed the diagnosis to be GBM. Five previously reported similar cases are reviewed, reflecting diversity in clinical and radiological findings and indicating that a high index of clinical suspicion must be maintained in patients with TSC.

Solid non-enhancing cerebellar pilocytic astrocytoma case report.

Pilocytic astrocytomas (PA) are slow-growing low-grade gliomas, commonly diagnosed as cerebellar tumors among the pediatric and adolescent population. Characteristic neuroradiologic findings in PA include a cystic mass with enhancing solid nodule. While uncommon radiologic features of PA, including non-enhancing cystic tumors, have been previously described, we present a unique case of a patient with a non-enhancing solid cerebellar PA. The main clinical, radiologic, and pathologic findings are discussed and the relevant literature reviewed. To our knowledge, this is the first reported patient with these radiologic features of PA, highlighting the need for awareness of uncommon presentations when discussing differential diagnosis and pre-operative planning for cerebellar tumors in the relevant age group.

RIPK1 regulates RIPK3-MLKL-driven systemic inflammation and emergency hematopoiesis.

Upon ligand binding, RIPK1 is recruited to tumor necrosis factor receptor superfamily (TNFRSF) and Toll-like receptor (TLR) complexes promoting prosurvival and inflammatory signaling. RIPK1 also directly regulates caspase-8-mediated apoptosis or, if caspase-8 activity is blocked, RIPK3-MLKL-dependent necroptosis. We show that C57BL/6 Ripk1(-/-) mice die at birth of systemic inflammation that was not transferable by the hematopoietic compartment. However, Ripk1(-/-) progenitors failed to engraft lethally irradiated hosts properly. Blocking TNF reversed this defect in emergency hematopoiesis but, surprisingly, Tnfr1 deficiency did not prevent inflammation in Ripk1(-/-) neonates. Deletion of Ripk3 or Mlkl, but not Casp8, prevented extracellular release of the necroptotic DAMP, IL-33, and reduced Myd88-dependent inflammation. Reduced inflammation in the Ripk1(-/-)Ripk3(-/-), Ripk1(-/-)Mlkl(-/-), and Ripk1(-/-)Myd88(-/-) mice prevented neonatal lethality, but only Ripk1(-/-)Ripk3(-/-)Casp8(-/-) mice survived past weaning. These results reveal a key function for RIPK1 in inhibiting necroptosis and, thereby, a role in limiting, not only promoting, inflammation.