The histological changes that accompany postvaccinal lymphadenitis may be misinterpreted as indicative of one of the malignant lymphomas, says a pathologist at the Armed Forces Institute of Pathology.
"It is important for the physician to be aware of this diagnostic pitfall," said Robert J. Hartsock, MD, chief of the AFIP's Hematological Pathology Branch. "In 20 documented cases of postvaccinal lymphadenitis received at the AFIP, an initial diagnosis of malignant lymphoma was made in nine, and in a tenth patient, a follicular lymphoma was suspected."
In 14 of these patients, the history of vaccination was overlooked before surgery, and in none was an operation necessary, Dr. Hartsock told the meeting of the American Society of Clinical Pathologists.
Postvaccinal lymphadenitis, a reactive response of the lymph node to vaccination, can be distinguished histologically from the malignant lymphomas primarily by the presence of stimulated histiocytes that intermingle with lymphocytes and impart a mottled