Pathology Report

Gross examination revealed a 65x45x32mm nodular mass attached to a portion of cardiac muscle (Fig 2). The cut surface showed an infiltrative solid white lesion containing areas of necrosis and haemorrhage (Fig 3). Histologic examination revealed a heterogeneous sarcomatoid malignancy with lobular architecture, widely invading the myocardium (Fig 4, 5 and 6). The constituent tumour cells were spindled and epithelioid, arranged in diffuse sheets and interlacing fascicles within a background of variably myxoid stroma. A spectrum of nuclear atypia was seen, including moderately pleomorphic blunt nuclei with vesicular chromatin transitioning to areas with marked cytologic atypia. Frequent mitotic figures were identified, numbering up to 32 per 10 high power fields (Figure 7). Broad zones of necrosis were present and lymphovascular invasion was identified.
Immunohistochemistry revealed the tumour cells to be positive for smooth muscle actin and desmin (Fig 8 and 9), with only focal positive staining for pan-cytokeratin and AE1/AE3. The tumour cells were negative for CK7, CK20, EMA, myogenin, MYO D1, STAT 6, calretinin, CD31, CD34, ERG, SOX 10, S100 and p40.
The morphologic features and immunohistochemical profile were in keeping with a high grade cardiac leiomyosarcoma.