Neorickettsia helminthoeca associated lymphoid,enteric, and pulmonary lesions in dogs from Southern Brazil: An immunohistochemical study

Neorickettsia helminthoeca (NH), the agent of salmon poisoning disease or canine neorickettiosis (CN), is a bacterial endosymbiont of the nematode Nanophyetus salmincola, and infections are spreading among specific fish‐eating mammalians. This article describes the pathologic and immunohistochemical findings associated with spontaneous NH‐induced infections in dogs from Southern Brazil. The principal pathologic findings were hypertrophy of Peyer patches and lymphadenopathy with lymphocytic proliferation, chronic interstitial pneumonia, and chronic enteritis associated with positive intralesional immunoreactivity to antigens of NH within macrophages and histiocytes. Positive immunoreactivity against canine parvovirus‐2 (CPV‐2) or/and canine distemper virus was not detected in the evaluated intestinal segments or in the samples from the cerebellum and lungs, respectively, from the dogs evaluated. These findings demonstrated that NH was involved in the enteric, pulmonary, and lymphoid lesions herein described, and provide additional information to confirm the occurrence of this bacterial endosymbiont within this geographical location. It is proposed that chronic pneumonia should be considered as a pathologic manifestation of NH‐induced infections. Additionally, our results show that the occurrences of CN seem to be underdiagnosed in Southern Brazil due to the confusion with the incidence of CPV‐2.     

Tyrosinemia type 1 in pediatric nephrology: Not always straightforward

The main clinical features of tyrosinemia type 1 usually appear in the first months of life, including fever, diarrhea, vomiting, liver involvement, growth failure, and renal proximal tubulopathy with subsequent hypophosphatemic rickets. An early diagnosis is crucial in order to provide specific management and to prevent complications. Here, we report on two cases referred primarily to pediatric nephrologists for the diagnosis of “neonatal tubulopathy” and management of “X-linked hypophosphatemia (XLH),” respectively. Our aim is to emphasize that (1) even a mixed tubulopathy can reveal tyrosinemia, and (2) tyrosinemia is a classic differential diagnosis of XLH that should not be forgotten, especially in the era of the anti-FGF23 burosumab.     

Fibrous dysplasia of the jaws: Integrating molecular pathogenesis with clinical,radiological, and histopathological features

Fibrous dysplasia is a non‐neoplastic developmental process that affects the craniofacial bones, characterized by painless enlargement as a result of bone substitution by abnormal fibrous tissue. Postzygotic somatic activating mutations in the GNAS1 gene cause fibrous dysplasia and have been extensively investigated, as well as being helpful in the differential diagnosis of the disease. Fibrous dysplasia may involve one (monostotic) or multiple bones (polyostotic), sporadically or in association with McCune‐Albright syndrome, Jeffe‐Lichenstein syndrome, or Mazabreud syndrome. This review summarizes the current knowledge on fibrous dysplasia, emphasizing the value of integrating the understanding of its molecular pathogenesis with the clinical, radiological, and histopathological features. In addition, we address important aspects related to the differential diagnosis and patient management.