My initial differential diagnosis was leishmania infection.
Called CDC, and I was told that leishmania is rare in US and
Chagas disease should be considered.
Got more clinical history: Patient grew up in Mexico on farm
with farm animals, and moved to US at age 18. He initially
presented with non-ischemic cardiomyopathy in 2001 following
viral illness, then developed heart failure in 2009, and
eventually underwent heart transplant in 2010. No other family
members had heart disease (11 siblings).
In 2010, the explanted heart was sent to a cardiac pathologist
for consultation with a descriptive diagnosis as “chronic
Histologic examination on 2010 explanted heart did not show
convincing morphologic evidence of microorganisms
Peripheral blood smears did not show active amastigotes
Both 2010 heart and 2013 lymph node were sent to CDC:
Immunohistochemical stains negative for Trypanosoma cruzi,
Leishmania spp or Toxoplasma gondii
PCR positive for Trypanosoma cruzi but negative for
Leishmania spp or T. gondii
Patient fresh serum was also sent to CDC for serology studies:
Follow-up: Bendnidazole received from CDC to treat the patient.
As of 08/02/2017 (4 years later), patient was doing well with no
new lymphadenopathy or abnormal function of the transplanted
Personal note: For reactive lymph nodes with areas of monocytoid
B-cell hyperplasia, I often spend some time at high power
magnification to search for possible infectious process in these
areas. Luckily so far I have identified 3 cases of CMV infection
and this Chagas disease.