Richard A. Carr

Differentiating the pathologies of cerebral malaria by postmortem parasite counts

To study the pathogenesis of fatal cerebral malaria, we conducted autopsies in 31 children with this clinical diagnosis. We found that 23% of the children had actually died from other causes. The remaining patients had parasites sequestered in cerebral capillaries, and 75% of those had additional intra- and perivascular pathology. Retinopathy was the only clinical sign distinguishing malarial from nonmalarial coma. These data have implications for treating malaria patients, designing clinical trials and assessing malaria-specific disease associations.

Platelet accumulation in brain microvessels in fatal pediatric cerebral malaria

The pathogenesis of fatal cerebral malaria (CM) is not well understood, in part because data from patients in whom a clinical diagnosis was established prior to death are rare. In a murine CM model, platelets accumulate in brain microvasculature, and antiplatelet therapy can improve outcome. We determined whether platelets are also found in cerebral vessels in human CM, and we performed immunohistopathology for platelet-specific glycoprotein, GPIIb-IIIa, on tissue from multiple brain sites in Malawian children whose fatal illness was severe malarial anemia, CM, or nonmalarial encephalopathy. Platelets were observed in 3 locations within microvessels: between malaria pigment and leukocytes, associated with malaria pigment, or alone. The mean surface area of platelet staining and the proportion of vessels showing platelet accumulation were significantly higher in patients with CM than in those without it. Platelet accumulation occurs in the microvasculature of patients with CM and may play a role in the pathogenesis of the disease.

Correlation of retinal haemorrhages with brain haemorrhages in children dying of cerebral malaria in Malawi.

Retinal haemorrhages increase in number with severity of Plasmodium falciparum malaria and occur in 35-40% of children with cerebral malaria. We performed clinical retinal examinations and histopathological examinations of retina, and parietal and cerebellar sections of the brains, in 33 children in Malawi who died with cerebral malaria, severe malaria anaemia, or coma of other causes. Haemorrhages were counted in a standardized fashion: the Spearman correlation coefficient between the number of haemorrhages in retina and brain was 0.741 for parietal tissue and 0.703 for cerebellar (P < 0.01 for both). Severity of haemorrhage in the retina correlates well with that in the brain. Retinal examination in cerebral malaria is a useful tool in predicting some of the pathophysiological processes occurring in the brain.

The systemic pathology of cerebral malaria in African children

Pediatric cerebral malaria carries a high mortality rate in sub-Saharan Africa. We present our systematic analysis of the descriptive and quantitative histopathology of all organs sampled from a series of 103 autopsies performed between 1996 and 2010 in Blantyre, Malawi on pediatric cerebral malaria patients and control patients (without coma, or without malaria infection) who were clinically well characterized prior to death. We found brain swelling in all cerebral malaria patients and the majority of controls. The histopathology in patients with sequestration of parasites in the brain demonstrated two patterns: (a) the “classic” appearance (i.e., ring hemorrhages, dense sequestration, and extra-erythrocytic pigment) which was associated with evidence of systemic activation of coagulation and (b) the “sequestration only” appearance associated with shorter duration of illness and higher total burden of parasites in all organs including the spleen. Sequestration of parasites was most intense in the gastrointestinal tract in all parasitemic patients (those with cerebral malarial and those without).

Pulmonary pathology in pediatric cerebral malaria

Respiratory signs are common in African children where malaria is highly endemic, and thus, parsing the role of pulmonary pathology in illness is challenging. We examined the lungs of 100 children from an autopsy series in Blantyre, Malawi, many of whom death was attributed to Plasmodium falciparum malaria. Our aim was to describe the pathologic manifestations of fatal malaria; to understand the role of parasites, pigment, and macrophages; and to catalog comorbidities. From available patients, which included 55 patients with cerebral malaria and 45 controls, we obtained 4 cores of lung tissue for immunohistochemistry and morphological evaluation. We found that, in patients with cerebral malaria, large numbers of malaria parasites were present in pulmonary alveolar capillaries, together with extensive deposits of malaria pigment (hemozoin). The number of pulmonary macrophages in this vascular bed did not differ between patients with cerebral malaria, noncerebral malaria, and nonmalarial diagnoses. Comorbidities found in some cerebral malaria patients included pneumonia, pulmonary edema, hemorrhage, and systemic activation of coagulation. We conclude that the respiratory distress seen in patients with cerebral malaria does not appear to be anatomic in origin but that increasing malaria pigment is strongly associated with cerebral malaria at autopsy.

A histological method for quantifying Plasmodium falciparum in the brain in fatal paediatric cerebral malaria

BackgroundThe sequestration of Plasmodium falciparum-infected erythrocytes in brain microvasculature through cytoadherence to endothelium, is the hallmark of the definitive diagnosis of cerebral malaria and plays a critical role in malaria pathogenesis. The complex pathophysiology, which leads each patient to the final outcome of cerebral malaria, is multifaceted and thus, metrics to delineate specific patterns within cerebral malaria are needed to further parse patients.MethodsA method was developed for quantification utilizing counts of capillary contents (early-stage parasites, late-stage parasites and fibrin) from histological preparations of brain tissue after death, and compared it to the standard approach, in which the percentage of parasitized vessels in cross-section is determined.ResultsWithin the initial cohort of 50 patients, two different observers agreed closely on the percentage of vessels parasitized, pigmented parasites and pigment globules (ICC = 0.795-0.970). Correlations between observers for correct diagnostic classification were high (Kendall’s tau-b = 0.8779, Kappa = 0.8413). When these methods were applied prospectively to a second set of 50 autopsy samples, they revealed a heterogeneous distribution of sequestered parasites in the brain with pigmented parasites and pigment globules present in the cerebellum > cortex > brainstem. There was no difference in the distribution of early stages of parasites or in the percentage of vessels parasitized across the same sites. The second cohort of cases was also used to test a previously published classification and regression tree (CART) analysis; the quantitative data alone were able to accurately classify and distinguish cerebral malaria from non-cerebral malaria. Classification errors occurred within a subclassification of cerebral malaria (CM1 vs CM2). A repeat CART analysis for the second cohort generated slightly different classification rules with more accurate subclassification, although misclassification still occurred.ConclusionsThe traditional measure of parasite sequestration in falciparum malaria, the percentage of vessels parasitized, is the most reliable and consistent for the general diagnosis of cerebral malaria. Methods that involve quantitative measures of different life cycle stages are useful for distinguishing patterns within the cerebral malaria population; these subclassifications may be important for studies of disease pathogenesis and ancillary treatment.

Extensive mucinous metaplasia of the vulva arising within Zoon's vulvitis

SIR, Mucinous metaplasia of the genital skin is a rare entity characterized by mucin-containing cells within or replacing the stratified squamous epithelium. We report a case of extensive mucinous metaplasia of the vulva with haemosiderin deposition arising within Zoon’s vulvitis. We discuss the pathogenesis and differential diagnosis of mucinous epithelium in the lower genital tract. A 67-year-old woman initially presented with a small, welldemarcated, red/brown macule on the labia minora. A biopsy from 1995 (Fig. 1) had been reported as lichen sclerosus and serial biopsies from 2002–2004 confirmed chronic inflammation, without neoplasia, but did not give a specific diagnosis for the inflammatory process. On review in 2005, she now had a 10-year history of vulval soreness which had not responded to conjugated oestrogen cream and potent topical steroids. The lesions had gradually enlarged to involve the inner aspects of both labia minora, the clitoral hood and one side of the introitus (Fig. 2a). The differential diagnosis included purpura secondary to lichen sclerosus, Zoon’s vulvitis, extramammary Paget’s disease, vulval intra-epithelial neoplasia and melanoma. All of the biopsies were reviewed. The 1995 biopsies showed a thinned epidermis with spongiosis and lozengeshaped keratinocytes, and a dense, band-like plasma cell-rich infiltrate in the corium without overt interface damage, in keeping with Zoon’s vulvitis. There were plasma cells, lymphocytes and scanty neutrophils in the corium. In addition, there were dilated capillaries, some red cell extravasation and mild haemosiderin deposition (Fig. 1a–d). Biopsies taken between 2002 and 2004 showed focal residual features of

Eruptive disseminated superficial porokeratosis with rapid resolution: a drug‐induced phenomenon?

We report a case of eruptive disseminated superficial porokeratosis occurring in a 63‐year‐old man with no history of excessive sun exposure. Unlike disseminated superficial actinic porokeratosis, this condition resolved rapidly with minimal topical treatment. This is most likely to have represented a drug‐induced phenomenon, which is very rarely reported in the dermatological literature.

Large germline deletions of the CYLD gene in patients with Brooke-Spiegler syndrome and multiple familial trichoepithelioma.

Abstract:Brooke–Spiegler syndrome (BSS) and its phenotypic variants, multiple familial trichoepithelioma (MFT) and familial cylindromatosis, are rare autosomal dominant hereditary diseases. They are characterized by the presence of multiple adnexal tumors, especially cylindromas, spiradenomas, spiradenocylindromas, and trichoepitheliomas. Implicated in the pathogenesis of the disease is the gene CYLD, which is localized on the long arm of chromosome 16. This gene encodes an evolutionarily conserved protein belonging to the deubiquitinating enzymes family, which plays a key role in many signaling pathways, especially in NF-&kgr;B, JNK, and Wnt. Less than 90 germline mutations of CYLD have been identified in patients with BSS/MFT. These mutations are mostly small alterations in the coding sequence and at exon–intron junction sites. One patient with an intronic mutation and another with a large CYLD deletion have also been recorded. In this study, the authors have analyzed a cohort of 14 patients with BSS/MFT from 13 families for large genome rearrangements by array comparative genome hybridization followed by confirmatory sequencing. We identified 2 large deletions, namely c.-34111_*297858del378779 and c.914-6398_1769del13642ins20 in patients with MFT and BSS, respectively. All other analyzable patients did not reveal any copy number alteration. It is concluded that the large rearrangements are relatively rare in patients without a germline CYLD mutation demonstrable by conventional sequencing. The pathogenetic mechanisms in patients with BSS/MFT lacking germline sequence alterations or large rearrangements in the CYLD gene remain to be clarified.

Lentigo maligna involving the tumour nests and stroma of a nodular basal cell carcinoma.

and nodular neurofibromas (Fig. 1). During a debriefing workshop, the panel of experts offered two main explanations for these findings: (i) pictures do not provide information on palpation; and (ii) there is absolutely no consensus on terminology. In order to take our next step and reach that consensus, we will recruit experts from other medical disciplines and provide more clinical information about each type of lesion (palpation, pain, localization and skin surface modifications).