Linfomatosis cerebral como causa de leucoencefalopatía / Lymphomatosis cerebri as the cause of leukoencephalopathy

La linfomatosis cerebral (LC) es un tipo poco frecuente de linfoma primario del sistema nervioso centralcaracterizado por la afectación difusa e infiltrante de la sustancia blanca cerebral sin formar una masa. Objetivo. Presentar el caso de una paciente con LC para llamar la atención sobre la existencia de esta enfermedad, raramente diagnosticada, y sobre su presentación inicial en la resonancia magnética (RM) como leucoencefalopatía. Caso clínico. Mujer de 56 años que inició un cuadro de demencia subaguda. La tomografía axial computarizada y la RM craneal revelaron una afectación extensa, difusa y bilateral de la sustancia blanca, núcleos basales, mesencéfalo y protuberancia, sin efecto masa ni captación de contraste. Biopsia estereotáxica de la sustancia blanca, no concluyente, que mostró un infiltrado inflamatorio mononuclearmixto, de células B y T, de disposición perivascular. No se observó atipia citológica. Se realizó tratamiento con corticoides, con lo que se obtuvo mejoría clínica y radiológica en los dos primeros meses. Al siguiente mes se produjo un deterioro clínico rápido con somnolencia y empeoramiento de la marcha. La RM mostró un aspecto más heterogéneo de la lesión, con efecto masa sobre estructuras adyacentes y realce parcheado del contraste. Una biopsia cerebral en cuña llevó al diagnóstico de linfoma de células B de alto grado. Conclusiones. La apariencia radiológica e histológica de la LC puede no ser la habitual de los linfomas primarios del sistema nervioso central, y su presentación clínica puede ser similar a la de otros procesos difusos de afectación de la sustancia blanca (gliomatosis cerebral, enfermedades inflamatorias de la sustancia blanca como la enfermedad de Behçet, la enfermedad de Sjögren o el lupus eritematoso sistémico)

Lymphomatosis cerebri (LC) is an infrequent type of primary lymphoma of the central nervous systemthat is characterised by diffuse, infiltrating involvement of the white matter of the brain without the formation of a mass. Aim. To report the case of a patient with LC in order to draw attention to this disease, which is rarely diagnosed, and to its initialpresentation in magnetic resonance imaging (MRI) as leukoencephalopathy. Case report. Our patient was a 56-year-old female who had clinical signs and symptoms of sub-acute dementia. Computerised axial tomography and MRI of the head revealed extensive, diffuse and bilateral involvement of the white matter, basal nuclei, mesencephalon and pons, with no masseffect or contrast enhancement. A stereotactic biopsy of the white matter (which was not conclusive) showed a perivascular mixed mononuclear-cell inflammatory infiltrate of B and T cells. No cytologic atypia was observed. Treatment was establishedwith corticoids, which produced a clinical and radiological improvement in the first two months. During the next month the patient underwent rapid clinical deterioration with sleepiness and a worsening of the ability to walk. In an MRI scan the lesion had a more heterogeneous appearance with mass effect on adjacent structures and patchy contrast enhancement. A wedge biopsy of brain tissue led to a diagnosis of high-grade B-cell lymphoma. Conclusions. The imaging and histological appearance of LC may not be the one typically found in primary lymphomas of the central nervous system, and its clinical presentation may be similar to that of other diffuse processes involving compromise of the white matter (cerebral gliomatosis, inflammatory diseases of the white matter, such as Behçet’s disease, Sjögren’s disease or systemic lupus erythematosus)

[Lymphomatosis cerebri as the cause of leukoencephalopathy]. / Linfomatosis cerebral como causa de leucoencefalopatía.

INTRODUCTION: Lymphomatosis cerebri (LC) is an infrequent type of primary lymphoma of the central nervous system that is characterised by diffuse, infiltrating involvement of the white matter of the brain without the formation of a mass. AIM: To report the case of a patient with LC in order to draw attention to this disease, which is rarely diagnosed, and to its initial presentation in magnetic resonance imaging (MRI) as leukoencephalopathy. CASE REPORT: Our patient was a 56-year-old female who had clinical signs and symptoms of sub-acute dementia. Computerised axial tomography and MRI of the head revealed extensive, diffuse and bilateral involvement of the white matter, basal nuclei, mesencephalon and pons, with no mass effect or contrast enhancement. A stereotactic biopsy of the white matter (which was not conclusive) showed a perivascular mixed mononuclear-cell inflammatory infiltrate of B and T cells. No cytologic atypia was observed. Treatment was established with corticoids, which produced a clinical and radiological improvement in the first two months. During the next month the patient underwent rapid clinical deterioration with sleepiness and a worsening of the ability to walk. In an MRI scan the lesion had a more heterogeneous appearance with mass effect on adjacent structures and patchy contrast enhancement. A wedge biopsy of brain tissue led to a diagnosis of high-grade B-cell lymphoma. CONCLUSIONS: The imaging and histological appearance of LC may not be the one typically found in primary lymphomas of the central nervous system, and its clinical presentation may be similar to that of other diffuse processes involving compromise of the white matter (cerebral gliomatosis, inflammatory diseases of the white matter, such as Behçet's disease, Sjögren's disease or systemic lupus erythematosus).

THE DIET OF PLATYDORIS ARGO (GASTROPODA: NUDIBRANCHIA) AND THE DIETARY SPECIALIZATION OF SPONGE EATING DORIDS.

The diet of the dorid nudibranch Platydoris argo was studied in relation to prey availability, and under different environmental conditions to evaluate richness, evenness, and plasticity of its diet. In order to assess the availability of possible prey, the sponge assemblage at two different habitats was characterized. The results showed that P. argo is a relatively specialized benthic carnivore, feeding exclusively on spiculated demosponges. However, it has a relatively polyphagous diet (16 prey-species) and adapts well to contrasting patterns of prey availability at different sites. At the location with lower sponge diversity, the diet of P. argo included more prey categories, was more diverse, and less selective (lower dietary evenness), foraging preferentially on the most frequent resource, Stylopus dujardini. In contrast, at a station with a clearly more diverse and abundant sponge assemblage, the diet was more selective, and Phorbas tenacior was its principal component. Despite its trophic plasticity, P. argo displayed a specialized pattern of resource exploitation in terms of niche breadth within a given habitat. Foraging was focussed on one preferred prey (which changed from one habitat to another) as indicated by the significant positive selection indexes (S. dujardini = +0.29, P. tenacior = +0.74). The revision of quantitative data on the diet of so-called 'sponge eating dorids' indicates the existence of a more specialized guild of 'spiculated demosponge eating dorids'. Most species revised are 'non-stereotyped specialist', which indicates that they have a polyphagous and plastic diet but only exploit one or few main prey species in each habitat. However, obligate specialists, with a monophagous (or rather oligophagous) diet also seem to be present.

Histological study of Goniodoris castanea Alder and Hancock, 1845 (Nudibranchia, Doridoidea, Goniodorididae).

The major organ systems of Goniodoris castanea were investigated by histological means, with an emphasis on those structures that are difficult to see by dissection. The species is characterized by some peculiar features that are unique or seldom within the Nudibranchia, such as the complete absence of specialized vacuolated cells, the presence of globular salivary glands, the presence of cuticular structures in the proximal intestine, a muscular sphincter around the distal vaginal duct, and the position of the blood gland closer to the pericardium than to the nervous system. Some of these characters are discussed in a phylogenetic context, although a thorough phylogenetic analysis is preliminary, due to lack of knowledge of probably related species.