Transformation of benign fibroadenoma to malignant phyllodes tumor.

The transformation of a benign fibroadenoma into a phyllodes tumor is uncommon and unpredictable. We report the case of a 40-year-old woman with a core biopsy proven fibroadenoma that underwent transformation into a malignant phyllodes tumor after 3 years of size stability. We present ultrasound and magnetic resonance images, as well as pathology slides from core biopsy and surgical excision, to illustrate this transformation. It has been suggested that phyllodes tumors may be misdiagnosed as fibroadenomas by core biopsy. However, in this case, pathology supports correct initial diagnosis of fibroadenoma and demonstrates a portion of the original fibroadenoma along the periphery of the malignant phyllodes tumor.

Low prevalence of Chagas parasite infection in a nonhuman primate colony in Louisiana.

Chagas disease, an important cause of heart disease in Latin America, is caused by the parasite Trypanosoma cruzi, which typically is transmitted to humans by triatomine insects. Although autochthonous transmission of the Chagas parasite to humans is rare in the United States, triatomines are common, and more than 20 species of mammals are infected with the Chagas parasite in the southern United States. Chagas disease has also been detected in colonies of nonhuman primates (NHP) in Georgia and Texas, and heart abnormalities consistent with Chagas disease have occurred at our NHP center in Louisiana. To determine the level of T. cruzi infection, we serologically tested 2157 of the approximately 4200 NHP at the center; 34 of 2157 primates (1.6%) tested positive. Presence of the T. cruzi parasite was confirmed by hemoculture in 4 NHP and PCR of the cultured parasites. These results strongly suggest local transmission of T. cruzi, because most of the infected NHP were born and raised at this site. All 3 species of NHP tested yielded infected animals, with significantly higher infection prevalence in pig-tailed macaques, suggesting possible exploration of this species as a model organism. The local T. cruzi strain isolated during this study would enhance such investigations. The NHP at this center are bred for use in scientific research, and the effects of the Chagas parasite on infected primates could confuse the interpretation of other studies.