Acute myeloid leukemia with infiltration of thyroid gland complicating Hashimoto's thyroiditis.

We describe a case of acute myeloid leukemia with infiltration of thyroid gland complicating Hashimoto's thyroiditis. In Hashimoto's thyroiditis, the leukocyte function-associated antigen-1 (LFA-1)/intercellular vascular cell adhesion molecule-1 (ICAM-1) and very late antigen-4 (VLA-4)/vascular cell adhesion molecule-1 (VCAM-1) pathways in T lymphocytes and the vascular endothelium both play a role in the initiation and enhancement of lymphocyte recruitment to the thyroid glands during an autoimmune attack. The leukemic blast cells were positive for VLA-4 and negative for LFA-1 by immunohistochemistry. The presence of VLA-4 in blast cells might play a key role in the migration of blast cells to the thyroid glands.