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We report the case of a large tumor in the left kidney with necrotic and hemorrhagic features in a 7-month-old child, which was clinically and radiologically suggestive of a nephroblastoma. The tumor was a nodular mass measuring 8cm in diameter occupying two thirds of the kidney and presenting areas of necrosis and hemorrhage. No capsular rupture or renal sinus infiltration were found. Adjacent renal parenchyma appeared mascroscopically normal. Histologically, the tumor showed a strictly tubulopapillary architectural pattern with numerous psammomas. The initial hypothesis was a purely epithelial nephroblastoma. However, this hypothesis was rejected due to some immunohistochemical and histological characteristics and the final diagnosis was a metanephric adenoma. Metanephric adenoma is an exceptionally rare benign renal tumor in children. However, pathologists need to keep it in mind because simple surgical excision is curative., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

JXG is a benign lesion of unknown incidence. It is the most frequent type of non-langerhans histiocytosis with a median age of 2 years. It usually presents as isolated cutaneous lesions. Multiple lesions, especially over the head and neck, may occur. The skin lesions tend to regress slowly with time. Extra-cutaneous and visceral involvements have been observed, the most common site being the eye. When the lesions are numerous, they may persist, hence the need for treatment with corticosteroids or chemotherapy. Histologically, the lesion consists of histiocytes admixed with an inflammatory infiltrate of variable density. The lesions are initially monomorphic and very cellular, progressively enriched with multinucleated giant cells of Touton and foamy cells, followed by spindle cells. We report an 8-year old girl with JXG of early type without multinucleated and foamy cells. This case presented as a tumour in the inferior meatus of nasal cavity, clinically simulating a rhabdomyosarcoma. This atypical clinical and histological presentation with benign evolution should be recognized since it requires only local treatment., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

Chronic rejection is one of the main causes of late allograft failure and no therapy is currently available to prevent efficiently its development. Improving the comprehension of the mechanisms involved in the pathophysiology of chronic rejection is a mandatory step to propose innovative therapies that would prolong grafts' survival. Using the rat aortic interposition model of chronic vascular rejection, we have demonstrated that the intragraft inflammatory infiltrate progressively organized itself into a functional ectopic lymphoid tissue (tertiary lymphoid organ) supporting the local synthesis of alloantibody. Thus, during chronic rejection the graft is at the same time the target and the site of elaboration of the humoral allo-immune response. This hypothesis has been confirmed in the clinical setting by the analysis of human grafts (kidneys, hearts and lungs) removed for terminal failure due to chronic rejection. This lymphoid neogenesis process, previously identified in other chronic inflammatory diseases, occurs with a strikingly high frequency in chronically rejected grafts, suggesting that an additional mechanism synergizes to initiate the development of tertiary lymphoid organs during chronic rejection. We propose that the defective lymphatic drainage of chronically rejected organs triggers lymphoid neogenesis and we discuss the complex crosstalk between lymphoid neogenesis and lymphangiogenesis that takes place during chronic rejection.

A 84-year-old women underwent renal biopsy because of rapidly progressive renal failure. Rabeprazole induced interstitial nephritis was diagnosed. Interstitial nephritis may complicate the course of any proton pump inhibitor treatment. It is a rare and serious complication. Clinician's awareness of this adverse event is essential for early diagnosis and prompt recovery.

We describe a simple procedure to use skin biopsies for the diagnosis of Alport syndrome. The technique is based on the co-detection of alpha5 and alpha2 chains of collagen IV along the basal lamina of epidermis through an immunfluorescence technique. Eighty-five per cent of the cases of Alport syndrome are due to a mutation in the gene COL4A5, located on chromosome X, encoding the alpha5 chain of collagen IV. In this situation, the tissue expression of alpha5 chain is abnormal; in males, the absence of expression of alpha5 chain is pathognomonic for Alport syndrome; in females, the expression of alpha5 chain may be discontinuous because of X inactivation. The alpha2 chain is used as a positive control. We have studied skin biopsies from 55 patients (35 females, 20 males) with a suspicion of Alport syndrome, along with five controls. Immunofluorescence was performed on frozen tissue samples; for lecture, epifluorescence and confocal microscopy were compared. In controls, both chains were co-detected. In nine males out of 20, the expression of alpha5 was undetectable; it was preserved in the remaining cases. In female patients, the expression was discontinuous in 16 cases and undetectable in one. There was no difference in sensitivity between the two microscopic techniques. The co-detection of alpha5 and alpha2 chains of collagen IV in frozen skin biopsies is therefore proposed as a simple technique to diagnose Alport syndrome, but requires a good knowledge of the conditions of interpretation.

All over the causes of intractable diarrhea of infancy, microvillous inclusion disease is a rare congenital defect of intestinal brush border of unknown aetiology. An autosomal recessive inheritance is suggested by cases occurring in siblings and high incidence of consanguinity. The prognosis of the disease is extremely poor, as life can be sustained only by total parenteral nutrition. Combined bowel-liver or bowel transplantation is regarded as the only potentially life-saving therapy. We report a case of microvillous atrophy who undergone a combined bowel, colonic and liver transplantation, and discuss the tools allowing the light microscopic diagnosis.

Villous atrophy may have various etiologies. The diagnosis of villous atrophy relies on an intestinal biopsy which necessitates a perfect histological technique to assert the villous atrophy and its degree. The most frequent etiology is coeliac disease. Villous atrophy regresses with gluten free diet. The failure of a strict gluten free diet implies to exclude a refractory sprue thought to be the earliest form of enteropathy associated T cell lymphoma. The other etiologies of villous atrophy are unusual and could be observed in alpha chain disease, inflammatory and infectious diseases, immune disorders, and primitive ileal villous atrophy. Other etiologies characterize villous atrophy in children as cow milk allergy and epithelial abnormalities.