Retroperitoneal leiomyomatous tumours are rare, accounting for only 0.5-1.2% of retroperitoneal tumours. Most retroperitoneal smooth muscle tumours have been considered to be malignant, with little published evidence of the criteria for benignity. Retroperitoneal and intra-abdominal leiomyomas occur almost exclusively in adult women.
retroperitoneal leiomyomas resemble uterine leiomyomas, with a whorled cut surface. They should have three or less mitoses per 50 HPF and should be devoid of coagulative necrosis and atypia.
further studies are needed of tumours in the range of 4 to 10 mitoses / 50 HPF.
|
|
leiomyomas |
leiomyosarcomas |
|
|
35/351 |
10/101 |
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|
30/351 |
8/101 |
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1/29 : one tumour was focally positive.1 |
0/81 |
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0/291 |
0/81
|
||
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0/321 |
0/91
|
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20/29: all three tumours in men were negative. The other tumours occurred in women.1, 5/62 |
0/81
|
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26/31: one of three tumours in men showed limited positivity. The other tumours occurred in women.1, 6/62 |
0/81
|
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|
0/261 |
0/81
|
||
Parasitic uterine leiomyomas.
Cases of retroperitoneal leiomyomas with copious fat: myolipoma
Leiomyosarcoma: occur sin older women, have greater cellularity, mitotic activity and necrosis. They are not usually strongly positive for oestrogen receptor.
GIST; these tumours are more cellular than leiomyomas, may have an epithelioid morphology and are positive for CD117, usually positive for CD34, variably positive for SMA and rarely positive for desmin.
Schwannoma; positive for S-100 and negative for SMA
Solitary fibrous tumour; positive for CD34 and almost always negative for SMA and desmin.
Angiomyolipoma: positive for HMB-45, Melan-A and microphthalmia transcription factor.
This page last revised 30.6.2004.
©SMUHT/PW Bishop