Cardiac inflammatory myofibroblastic tumor in interventricular septum: A rare case report

Cardiac inflammatory myofibroblastic tumor (IMT) is a rare primary cardiac tumor which is currently considered as a low-grade neoplasm. The tumor has a predilection in infants and adolescents and primarily occurs as an endocardial-based cavitary mass. However, cardiac IMT that only involves the interventricular septum in middle-aged adults is extremely rarely reported. Considering its infrequency, we report a rare clinical case, with the aim of sharing our experience during the diagnostic procedures.

A 45-year-old, previously healthy female, with no medical history was admitted to the outpatient clinic due to the identification of an abnormal radiographic finding during a routine health examination.

Transthoracic echocardiography (TTE) revealed a 3.5 cm × 4.0 cm × 4.5 cm heterogeneous mass in the interventricular septum. Color Doppler echocardiography detected sparse blood flow signals inside the mass. Magnetic resonance imaging (MRI) confirmed a hyperintense T2-weighted, isointense T1-weighted mass. Three-dimensional (3D) TTE demonstrated a spherical mass in the middle part of the interventricular septum. Postoperative histopathological examinations revealed a mesenchymal tumor composed of scattered spindle myofibroblasts with a myxoid atypia, associated with infiltration of lymphocytes and plasma cells.

Complete tumor resection was successfully performed via median sternotomy under general anesthesia.

After surgery, the patient recovered successfully. The patient was in good general health without any clinical symptoms. The echocardiographic examination at the 12-month follow-up period revealed normal function of the heart, and there was no evidence of tumor recurrence.

To our knowledge, cardiac IMT only the involving interventricular septum in a middle-aged adult has never been previously reported before. Echocardiography plays a critical role in establishing the primary diagnosis of cardiac IMT and evaluating regular follow-up examinations. Complete surgical resection of the mass is considered the first-line treatment despite the absence of symptoms.