Pathological findings
Macroscopically, the resected huge solitary mesenteric tumour, which
measured 30x23x16.7cm and weighed 6500 grams, was well-circumscribed and
multinodular which appeared as a firm mass with a pinkish outer surface.
The cut surface was solid and pale yellowish-brown and showed areas of
necrosis (Figure 1).
Microscopically, the sections through the tumour mass show a highly
cellular tumour, characterized by spindle cells arranged in a storiform
pattern, and in areas in palisaded forms. There are other areas
exhibiting a herring-bone type pattern of arrangement. The cells are
spindle shaped, with markedly vesicular nuclei, and coarse chromatin
pattern, with many areas of palisaded necrosis(Figure 2,3 and 8).
Mitoses are readily seen, and in areas, nuclear pleomorphism with tumour
giant cell formation is prominent (Figure 4 and 5). Abnormal and bizarre
mitoses are observed. There is no evidence of pigmentation, osseous or
chondroid differentiation. The surgical margins are involved by the
malignant cells.
The tumour cells stained diffusely and strongly for STAT-6 (Figure 9),
bcl-2 (Figure 10) and CD34 (Figure 11). Staining for CD117, DOG-1,
S-100, Desmin, EMA and TLE-1 were negative. About 15% of cells show
MIB-1 activity.
*(To scan gross picture in JPEG)
Figure 1: The cut surface of the extrapleural (retroperitoneum)
malignant solitary fibrous tumour showed multinodular pale
yellowish-brown solid appearance with areas of necrosis