Fulminant cerebral venous thrombosis associated with the m.3243A>G MELAS mutation: A new guise for an old disease

Radiologic Findings in a Patient With Mitochondrial Encephalomyopathy With Lactic Acidosis and Stroke-Like Episodes Syndrome: A Case Report

Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome is a rare, genetically inherited mitochondrial disorder that typically manifests in childhood. The most common radiologic features include basal ganglia calcification, atrophy, and stroke-like cortical lesions. We present the case of an 18-year-old female patient with no known medical history who arrived at the emergency department with altered mental status following a suicide attempt. The patient's initial workup, including a computed tomography (CT) scan of the brain, revealed abnormal findings, prompting further investigation into the patient's medical history. It was later discovered that the patient had a previous diagnosis of MELAS syndrome. This diagnosis helped explain both the radiologic abnormalities and her psychiatric symptoms. This case underscores the importance of recognizing radiologic presentations of rare conditions such as MELAS syndrome, which may contribute to the broader spectrum of clinical manifestations associated with the disease.

Inflammatory features in sporadic late-onset nemaline myopathy are independent from monoclonal gammopathy

Sporadic late-onset nemaline myopathy (SLONM) is a rare adult-onset non-hereditary disease with subacute proximal muscle and often axial muscle weakness, characterized by the presence of nemaline bodies in skeletal muscle biopsies. Considering its association with concurrent monoclonal gammopathy of undetermined significance (MGUS), the disease is classified into two major subtypes (1) SLONM without MGUS (SLONM-noMGUS) and (2) with MGUS (SLONM-MGUS) association. SLONM associated with HIV infection (SLONM-HIV) is also reported. SLONM-MGUS has been shown to be associated with poorer prognosis and required aggressive treatment including high-dose melphalan and autologous stem cell transplantation. The approach is currently debatable as recent reports suggested effectiveness of intravenous immunoglobulin as initial treatment with indifference of overall survival despite the presence of MGUS. Our study aimed to find an underlying basis by review of pathological features in 49 muscle biopsy proven-SLONM from two large tertiary centers in Japan and Germany (n = 49: SLONM-noMGUS = 34, SLONM-MGUS = 13, SLONM-HIV = 2). We compared pathological findings in SLONM-noMGUS and SLONM-MGUS and focused on the presence of any detectable inflammatory features by immunohistochemistry. The clinical and histological features in SLONM-noMGUS and SLONM-MGUS were not distinctively different except for more common regenerating fibers (>5% of myofibers) present in SLONM-MGUS (p < 0.01). HLA-ABC expression and fine granular p62 were observed in 66.7% and 78.3% of SLONM, respectively. The predominant inflammatory cells were CD68⁺ cells. The inflammatory cells showed positive correlations with the percentage of nemaline-containing fibers (p < 0.001). In conclusion, inflammatory features are present although rather mild in SLONM. This finding contributes to the hypothesis of an acquired inflammatory disease pathogenesis and opens the possibility to offer immunotherapy in SLONM with inflammatory features regardless of the monoclonal gammopathy status.