What's the cause of this
gingival enlargement?

June 7, 2017

Matthew Stevenson, MD
Shyam Patel, MD


Case Presentation:

This patient presented with gingival swelling and bleeding after a dental procedure. He thought it was a reaction to novocaine, but he soon developed fatigue, easy bruising, and unintentional weight loss.  Meanwhile, the gingival swelling only worsened.  He presented to a local hospital, where this finding was noted on oral exam. What is the diagnosis?


Image from Stanford Medical Center Case








Acute myeloid leukemia, subtype M5 


What is acute myeloid leukemia, subtype M5?

AML M5 is a subtype of acute myeloid leukemia and specifically refers to leukemia with monocytic blasts. There are 8 subtypes of AML based on the French-American-British (FAB) classification: M0 through M7. Each subtype is characterized by a blast population that is from a particular lineage or particular stage of maturation.

Gingival hyperplasia noted by arrows and seen thoughout.

How common is gingival infiltration as a manifestation of AML M5?

Extramedullary involvement of leukemia can occur in up to 40% of patients. One of the rarest sites of extramedullary involvement is the oral cavity, with only 5% or less of all patients with AML present with gum infiltration.  Among the AML M5 subtype it is a oral manifestation of leukemia subtype—Acute Monocytic Leukemia—which is seein in  approximately 66% of these types of cases.


What other tests should you order?

A peripheral blood smear can show myeloid blasts in many cases. A bone marrow biopsy is critical to the diagnosis of AML.AML is diagnosed by the presence of 20% of greater blasts in the bone marrow. Alternatively, it can be diagnosed by <20% blasts in the presence of known cytogenetic abnormalities associated with AML, such as t(8;21) or t(15;17).

What is the differential diagnosis?

The differential diagnosis of gingival hyperplasia includes poor oral hygiene, medications like cyclosporine and phenytoin, systemic illnesses like sarcoidosis or Crohn’s disease, hematological disorders like AML, and genetic conditions. Patients can experience gingival hyperplasia because of leukemic infiltration into the gums. Treatment is induction chemotherapy, which results in normalization of the gums.

What happened to our patient?

The patient received induction chemotherapy with IV cytarabine and daunorubicin. Within 3 days, he noted improvement in his gum infiltration. He was able to eat normally without pain. His gum bleeding resolved as the infiltration resolved.

Subscribe to our mailing list