Cardiac Myxoma : Osseous Metaplasia

Comments:
Microscopic Features: Some myxomas (especially right-sided tumors) show calcification and cartilaginous or osseous metaplasia (shown here). Other rare findings include extramedullary hematopoiesis, thymic remnants, and intestinal-type mucinous glands arising from foregut remnants (glandular myxomas; 2% of cases).

Cytologic atypia, increased cellularity, any mitotic activity, and necrosis are generally absent in cardiac myxomas. Presence of any of these features is highly suggestive of a malignant diagnosis such as myxosarcoma. Multiple sections must be examined to avoid missing a low-grade sarcoma.