Renal Leukemic Infiltration Overlapping Acute Focal Bacterial Nephritis during Myelodysplastic Syndrome: An Autopsy Case Report.

Renal leukemic infiltration is uncommon in myeloid neoplasms, including myelodysplastic syndromes (MDS). A 76-year-old male patient was admitted to our hospital with complaints of fever and dyspnea. He was diagnosed with MDS with multilineage dysplasia and acute focal bacterial nephritis (AFBN) based on clinical, laboratory, and radiological investigations. Antibiotic treatment temporarily improved his condition, but the radiological image of AFBN remained. His condition gradually deteriorated into multiple organ failure, and he unfortunately died on the 31st day of hospitalization. Autopsy findings revealed significantly increased p53-positive blasts in the bone marrow and renal parenchyma overlapping AFBN, suggesting leukemic transformation and renal infiltration. This case emphasizes the need to review the diagnosis when antibiotic treatment is ineffective in MDS patients with AFBN.

Familial schwannomatosis carrying LZTR1 variant p.R340X with brain tumor: A case report.

Schwannomatosis (SWN) is a rare genetic condition characterized by the risk of developing multiple benign peripheral nerve sheath tumors; however, the risk of developing malignant tumors in patients with SWN remains unclear. This study described the case of a 57-year-old Japanese man diagnosed with SWN whose older brother also had SWN. Whole-exome sequencing identified a heterozygous mutation [c.1018C > T (p.Arg340X)] in the LZTR1 gene, linked to the RAS/MAPK pathway, in the patient and his brother. Moreover, the patient had aphasia and right-sided paralysis because of a brain tumor. RNA sequencing revealed the remarkable upregulation of several genes associated with oxidative stress, such as the reactive oxygen species pathway and oxidative phosphorylation, a downstream effector of the RAS/MAPK pathway, in the the patient and his brother compared with healthy volunteers. The final diagnosis was LZTR1-related familial SWN, and the dysregulated RAS/MAPK pathway in this patient might be associated with brain tumorigenesis.