同意前列腺间质肉瘤的诊断，肿瘤细胞排列密集，异型较明显，分裂像易见，够恶性了。与前列腺平滑肌等来源的间质肿瘤区别是CD34阳性。PR阳性也证明它是来源与前列腺特化性间质。WHO书中说Actin可用于恶性潜能未定的前列腺间质增生瘤（STUMP）与前列腺间质肉瘤区别，前者可阳性，后者阴性。本例中肌源性表达可能是残留的前列腺间质。

Based on the cellularity and increased mitosis, it is a sarcoma.  STUMP is one of the differential diagnoses. I do not know if the case has bizarre mitoses, bizarre mitosis will warrant a diagnosis of stromal sarcoma. Both STUMP and stromal sarcoma can have the overall glandular growth pattern. Stromal sarcoma may also have hypercellular stroma surrounding normal glands like STUP. Both STUMP and stromal sarcoma have a positive stain for CD34, which is good for differentiating from other spindle lesion such as leiomyosarcoma, rhabdomyosarcoma. STUMP and stromal sarcoma characteristically express PR and uncommonly EP.

Regarding management stromal sarcoma needs a surgical excision. STUMP is based on age. Older patient can be closely followed up if the lesion does not grow fast. Young patient should have surgery.

 同意，考虑恶性潜能未定的间质肿瘤（STUMP）伴有间质肉瘤（stromal sarcoma），STUMP和stromal sarcoma可以单发也可以混合存在。鉴别诊断为其他梭形细胞病变，主要包括SFT，平滑肌源性肿瘤甚至GIST（不同于前列腺间质肿瘤，多为直肠GIST累及前列腺，c-kit可以鉴别）。此例梭形细胞围绕腺体生长，多见于前列腺间质肿瘤。免疫组化表达PR、CD34等，与平滑肌肿瘤的鉴别主要靠CD34和Ddesmin。