Nonmucinous adenocarcinoma of the cecum presenting as appendicitis complicated by hepatic abscess.

A 59-year-old man presenting with right upper quadrant pain was found to have hepatic abscesses on CT imaging. After draining the abscess, a repeat CT 3 weeks later indicated that the cause of the hepatic abscesses was appendicitis. Upon surgical resection of the base of the cecum and appendix, an adenocarcinoma was demonstrated along the cecal wall both invading and occluding the appendix. The patient was initially treated for complications of appendicitis, but this case indicates the importance of considering additional etiologies for complex appendicitis. This case report provides a pathology-proven case of well-differentiated, nonmucinous adenocarcinoma of the cecum presenting as a complication of appendicitis and discusses standard treatment options. This case report also reviews the pathophysiological aspects of hepatic abscess as a complication of appendicitis as well as the importance of considering malignancy in a patient presenting with complications of appendicitis.

Development of multiorgan pathology in the wpk rat model of polycystic kidney disease.

Rodent models of polycystic kidney disease (PKD) have provided valuable insight into the cellular changes associated with cystogenesis in humans. The present study characterizes the morphology of renal and extrarenal pathology of autosomal recessive PKD induced by the wpk gene in Wistar rats. In wpk(-/-) rats, proximal tubule and collecting duct cysts develop in utero and eventually consume the kidney. Increased apoptosis, mitosis, and extracellular tenascin deposition parallel cyst development. Extrarenal pathology occurs in the immune system (thymic and splenic hypoplasia) and central nervous system (CNS; hypoplasia to agenesis of the corpus callosum with severe hydrocephalus). Severity of hydrocephalus varied inversely with size of the corpus callosum. In wpk(-/-) rats, the corpus callosum exhibits relatively few axons that cross the midline. This CNS pathology is similar to that described in three human renal cystic syndromes: orofaciodigital, genitopatellar, and cerebrorenal-digital syndromes. Collecting duct and ventricular ependymal cilia appear morphologically normal. To determine if rodent background strain and the presence of modifier genes affect severity of the disease, we crossed the Wistar-wpk rat with Brown Norway (BN) and Long Evan (LE) rats and found the degree of renal and cerebral pathology was diminished as evidenced by lower kidney weight as a percent of body weight and serum urea nitrogen concentration in cystic rats on LE or BN strains as well as less prominent cranial enlargement. Crosses with BN rats allowed us to localize the wpk gene on chromosome 5 very close to the D5Rat73 marker. The wpk gene lies within a chromosomal region known to harbor a PKD modifier locus. In summary, the types of renal and cerebral pathology seen in the Wistar wpk rat are a unique combination seen only in this rodent model.