Acute actinomycotic brain abscess in a patient with rheumatoid arthritis.

An autopsy case of acute actinomycotic brain abscess involving a patient with rheumatoid arthritis (RA) is reported. The patient was a 72-year-old man with a seven-year history of RA and pulmonary complications, who acutely developed dysarthria and dysphagia three days before death. Autopsy revealed a fresh, non-encapsulated abscess in the "late cerebritis" stage, measuring 2 cm in diameter, in the white matter of the right parietal lobe. A small number of tiny "sulfur granules" consisting of numerous filamentous bacilli were found within the abscess. The abscess had ruptured to the lateral ventricle and elicited ventriculitis, and mild acute purulent leptomeningitis was also observed. The lung showed chronic interstitial pneumonia/pulmonary fibrosis with bronchiectasis and emphysema, and large sulfur granules were found in the lumens of a few bronchi. Less than 5% of patients with actinomycotic infection develop central nervous system lesions, and actinomycotic brain abscesses make up only 0.6% of all brain abscesses. Actinomycotic brain abscesses usually pursue a protracted clinical course, and well-formed pyogenic membranes are commonly observed. The present case is exceptional in that the very early stage of the cerebral abscess formation was pathologically captured.

Amyotrophic lateral sclerosis associated with pleuroparenchymal fibroelastosis.

An autopsy case of sporadic amyotrophic lateral sclerosis (ALS) associated with pleuroparenchymal fibroelastosis (PPFE), a rare form of idiopathic interstitial pneumonia, is reported. The patient, a 76-year-old man, presented with shortness of breath and dyspnea and died of progressive respiratory failure after a clinical course of 9 months. Muscle weakness and motor disturbance were mild, and the diagnosis of ALS was not established until one month prior to death. He had serum IgM-kappa monoclonal gammopathy (IgM: 1,232 mg/dL). Autopsy demonstrated ALS of the lower neuron-predominant type. The density of motor neurons in the spinal anterior horn showed a moderate decline, and many remaining neurons contained round inclusions that were immunoreactive for pTDP-43 (phosphorylated transactivation responsive DNA-binding protein of 43 kD) and ubiquitin. Betz cells and the pyramidal tracts were well preserved. The lung showed typical features of PPFE predominantly affecting the upper lobe: fibro-hyalinous thickening of the visceral pleura, a marked increase and aggregation of elastic fibers in the subpleural zone, and intra-alveolar collagenous fibrosis with an increase of elastic fibers in the alveolar septa. Although the complications from interstitial lung diseases including PPFE in ALS patients are usually regarded as incidental, PPFE is clinically important because of its markedly adverse influence on the clinical course. IgM-monoclonal gammopathy is another notable finding in the present case, which is occasionally seen in ALS patients, and the pathogenesis of PPFE is also considered to be associated with immunological derangements.