Giardia lamblia histology

(A) Low power view of a random biopsy specimen from the second portion of the duodenum shows a normal villous architecture in a patient with Giardia lamblia infection. The cellular elements of the lamina propria, lymphocytes and plasma cells, are at the upper limit of normal.
(B) Medium power and (C) and high power views demonstrate the flattened or pear shape trophozoites of Giardia lamblia. The organisms are both intraluminal (arrow and circle) and attached to the glycocalyx of the enterocyte (arrowhead).