Intravascular large B-cell lymphoma presenting with fever and refractory acidosis

Intravascular large B-cell lymphoma (IVLBCL) is a rare form of diffuse large B-cell lymphoma, characterized by malignant B-cells primarily localized to the lumina of small- and medium-sized blood vessels without lymphadenopathy. Two patients initially presented with fever of unknown origin and persistent lactic acidosis without evidence of tissue hypoxia. Neither patient had an identifiable source of infection and both underwent peripheral blood smear demonstrating leukocytosis with a neutrophilic predominance and thrombocytopenia without evidence of hematologic malignancy. One had previously had a bone marrow biopsy which was unremarkable. Both patients’ condition deteriorated rapidly, progressing to multiorgan failure requiring pressors and mechanical ventilation, which ultimately resulted in cardiopulmonary arrest. At autopsy, each patient demonstrated malignant lymphocytoid cells, staining positive for CD20, localized to the lumina of small- and medium-sized vessels in multiple organs, including the lungs, liver, spleen, and kidneys, among others, allowing for the diagnosis of IVLBCL. IVLBCL is exceedingly rare, which in combination with significant variability in presentation, can make identification and diagnosis challenging. Diagnosis requires biopsy, therefore a high index of suspicion is needed to obtain an adequate tissue sample, whether pre- or postmortem. In the presented cases, both patients exhibited type B lactic acidosis with an unknown etiology that was ultimately determined at autopsy.

Histiocytoid cardiomyopathy and sudden death

We present a case of histiocytoid cardiomyopathy resulting in sudden and unexpected death in a 4-month-old infant with Peter's Anomaly and congenital glaucoma. At autopsy, the granular histiocytoid cells that define this entity were found predominantly involving the conduction system, with encasement and partial replacement the His' Bundle. Large aggregates of these cells formed atrioventricular and nodoventricular connections, indicating a possible mechanism for the arrhythmias characteristic of the condition. The striking propensity for involvement of the conduction system in this case lends further support to the view that this disorder represents a developmental anomaly of the Purkinje cell system of the heart.

Hamartomatous malformation of the left ventricle associated with sudden death

We describe unusual left ventricular cardiac lesions in a 17 year old boy who died suddenly during exertion. These consisted of two grossly evident regions of deficient myocardium, containing cavernous spaces which represented exaggerated intertrabecular regions of the left ventricular cavity. Dense fibro-elastotic tissue was deposited around these spaces along with a variable admixture of mature adipose tissue, fibrous tissue and blood vessels. The etiology of these presumably congenital developmental abnormalities is obscure. The lesions most probably represent a hamartomatous malformation, which is a poorly documented pathological entity.

Melioidosis. Forgotten, but not gone!

Melioidosis, infection by the soil bacterium Pseudomonas pseudomallei, has the potential for prolonged latency with recrudescence into an acute, often fulminating, and fatal infection. Although the organism is never found in North America, infection is endemic in areas of southeast Asia, and populations of service personnel exposed during the Vietnam war and southeast Asian immigrants are at risk of severe recrudescent disease. Diagnosis, however, has been missed or delayed because of lack of familiarity with this disease. We present a case of recrudescent melioidosis that illustrates the difficulties encountered in diagnosis and treatment. This case involves a 76-year-old Vietnam veteran who presented with melioidosis of the bone 18 years after exposure to the organism and 10 years after a missed diagnosis of latent pulmonary disease. This case illustrates the protean nature of latent infection and the difficulty of selecting successful antibiotic therapy.