Clinical Medicine Insights- Pathology最新文献

Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare inherited autosomal recessive disorder that presents with thrombocytopenia and absence of megakaryocytes. It presents with bleeding recognized on day 1 of life or at least within the first month. The cause for this disorder appears to be a mutation in the gene for the thrombopoeitin (TPO) receptor, c-Mpl, despite high levels of serum TPO. Patients with severe Type I-CAMT carry nonsense Mpl mutations which causes a complete loss of the TPO receptor whereas those with Type II CAMT carry missense mutations in the Mpl gene affecting the extracellular domain of the TPO receptor. Differential diagnosis for severe CAMT includes thrombocytopenia with absent radii (TAR) and Wiskott-Aldrich syndrome (WAS). The primary treatment for CAMT is bone marrow transplantation. Bone Marrow/Stem Cell Transplant (HSCT) is the only thing that ultimately cures this genetic disease. Newer modalities are on the way, such as TPO-mimetics for binding towards partially functioning c-Mpl receptors and gene therapy. Prognosis of CAMT patients is poor, because all develop in childhood a tri-linear marrow aplasia that is always fatal when untreated. Thirty percent of patients with CAMT die due to bleeding complications and 20% -due to HSCT if it has been done.

Mounting evidence has demonstrated that the autonomic system plays a role in the morbidity and mortality of certain cardiovascular disease states. Ventricular arrhythmias have been associated with the level of sympathetic activation. We attempted to determine if the presence of fibrosis, a marker for previous ischemic events, correlates with an increase in the number of left stellate ganglion nerve cell bodies which is indicative of hypersympathetic stimulation to the myocardial tissue. Left stellate ganglia were removed, sectioned and prepared using hematoxylin and eosin and Masson's trichrome stain. The interventricular septum of the heart corresponding to the stellate ganglion samples were removed, serially sectioned, and stained with hematoxylin and eosin and Masson's trichrome stain. The samples were described using a grading scale to quantify the percentage of fibrosis. Ganglion nerve cell bodies were then individually counted in three separate high-powered fields. A student's T-test was used to statistically evaluate the data. Stellate ganglions were sampled from 32 cadavers. Fibrosis was present within 72% (23/32) of the interventricular septums that were sampled. Nine interventricular septums were found to be free of fibrosis. For those interventricular septums that were positive for the presence of fibrosis, the mean left stellate ganglion nerve cell bodies was 39.8 (Range: 26-51). For those interventricular septums that were negative for the presence of fibrosis, the mean left stellate ganglion nerve cell bodies was 34.3 (Range: 27-46). The difference between the mean nerve cell bodies for interventricular septums with fibrosis and without fibrosis was found to be statistically significant (P = 0.048). Histological changes in terms of the number of left stellate ganglion nerve cell bodies seem to be dependent upon the presence of fibrosis within the interventricular septum. Considering fibrosis of the interventricular septum is a marker for previous ischemic events, an increase in the number of nerve cell bodies of the left stellate ganglion in the presence of fibrosis suggests an association does exist between hypersympathetic stimulation to the myocardial tissue and myocardial infarction. Further research into this association is warranted in order to determine if left stellate ganglion blockade is a viable treatment option for arrhythmias following myocardial infarctions.

Thrombotic microangiopathies are disorders resulting from platelet thromboses forming in the microvasculature with resultant schistocyte forms. Hemolytic uremic syndrome (HUS) is a microangiopathic hemolytic anemia often complicated by acute renal failure in children. HUS is typically caused by bacterial infection, most commonly enterohemorrhagic Escherichia coli. Neuraminidase-producing organisms, such as Streptococcus pneumoniae have also been reported as potential etiologies. The pathogenesis in these cases involves cleavage of sialic acid residues from the surfaces of erythrocytes, platelets, and glomerular capillary endothelial cells, exposing the Thomsen-Friedenreich antigen, a process known as T-activation. We describe a 2-year-old girl who presented with pneumococcal pneumonia and sepsis ultimately resulting in a thrombotic microangiopathy with acute renal failure, most consistent with HUS. The patient's direct antiglobulin test was positive. Polyagglutination was observed with human adult serum, but not with umbilical cord serum. Her red blood cells (RBCs) were reactive against peanut and soybean lectins, but not Salvia sclarea or Salvia horminum lectins. These findings are consistent with T-activation. Clinicians should be cognizant of the possibility of T-activation with resultant HUS in patients infected with neuraminidase-producing bacteria. Such patients may be difficult to identify using monoclonal typing antisera, as these typically do not have anti-T antibodies. Whether such patients are at risk for transfusion-associated hemolysis is debatable.

Yersinia enterocolitica intussusception is rarely encountered in patients without an underlying susceptibility and is most frequently reported in iron-overloaded patients. This is thought to be related to the unusual use of iron by this microorganism. We present a case of a 5-year old child with intussusception of the terminal ileum caused by Y. enterocolitica whose past medical history was significant for sickle cell disease. This type of presentation is extremely rare. His monthly blood transfusions may have put him at risk for Y. enterocolitica enterocolitis. The pathogenesis of this disease relates to the role of iron as an essential growth factor for Y. enterocolitica, and this patient's transfusions left him in an iron overloaded state despite treatment with Deferoxamine. Our patient's unusual presentation of intusssuception was secondary to the mass effect caused by lymphoid hyperplasia, specifically hypertrophied Peyer's patches in the ileum caused by the Y. enterocolitica infection. We believe that our case demonstrates that Y. enterocolitica should be considered a possible pathogen in patients with sickle cell disease, especially if symptoms occur shortly after blood transfusion.

We report a rare case of bilateral basal cell adenocarcinoma (BcAC) of the parotid gland in a male patient 30 years after kidney transplantation and continuous administration of immunosuppressive therapy. BcAC is a salivary gland malignancy first recognized as a distinct neoplastic entity in WHO classification of salivary gland tumours in 1991. Over 90% of BcACs are detected in the parotid gland. The most important differential diagnosis is basal cell adenoma. Infiltrative growth is the distinguishing feature of BcAC. Administration of immunosuppressive medication to this patient for three decades may have contributed to development of this rare neoplasia. To our knowledge, similar cases of BcAC have not been reported previously.