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.