Inoperable plasma cell granuloma of the heart: spontaneous decrease in size during an 11-month period.

Plasma cell granuloma occurs in children, typically as an intrapulmonary mass. Surgical excision is the treatment of choice and is usually curative. We report an atypical and unresectable plasma cell granuloma that occurred asymptomatically in the heart of a child and spontaneously decreased in size by 40% during an 11-month period. Thus, plasma cell granuloma should be considered in the differential diagnosis of any child who has a cardiac mass. Observation should be considered a treatment option because this case demonstrated that the cardiac mass can spontaneously recede without therapy.