皮肤平滑肌肉瘤组织学类型及来源——附7例临床病理及免疫组化研究

目的探讨皮肤平滑肌肉瘤的病理类型,组织来源和预后。方法集7例皮肤平滑肌肉瘤进行临床,组织病理和免疫组化分析。结果①皮肤平滑肌肉瘤有结节性和弥漫性两种生长方式。组织学上结节性高度异型,弥漫型异型小。②免疫组化：7例肿瘤均表达Vimentin,SMA,HHF－35;4例表达S-1000p;1例Cytokeratin异型表达。肿瘤局部复发率57．1％,多次复发后组织学异型性增大,1例弥漫性肿瘤发生远处转移,1年后死亡。结论皮肤平滑肌肉瘤可分为坚毛肌和非竖毛肌来源,形态学上相应地表现为弥漫性和结节性两种不同的生长方式。弥漫性瘤细胞异型小,与皮肤附件关系密切,复发率高,个别多次复发可去分化。结节性组织学高度异型。本组远处转移率为14．5％。

Histological variants and histogenesis of cutaneous leiomyosarcoma-A clinicopathologic and immunohistochemical study of 7 cases

Objective To study the histological valiants, histogenesis, and biologic behaviors of cutaneous leiomyosarcoma .Methods Seven cases of cutaneous leiomyosarcoma were analyzed on both clinicopathologic and immunohistochemical aspectsResults Seven cases of cutaneous leiomyosarcomas showed two different growth patterns, namely nodular (4 cases ) and diffuse (3 cases). Neoplasms with diffuse growth pattern only appeared mild cytological atypia. Immunohistochemically , all tumors reacted positively with smooth muscle actin, pan-muscle actin (HHF-35) and vimentin. Four cases the expressed S-100 protein and one showed heterotgenic expression for cytokeratin 8. Follow-up data revealed 4 cases survived without tumor, 3 cases with tumor recurrences for 2 ~ 7 times. One patient died of tumor recurrence and multiple metastases. Histologically, the more times tumor recurs times, the greater atypia of the tumor appears . Conclusions Histogenesis of cutaneous leiomyosarcoma might derive from the pilar arrector smooth muscle (PASM) and non-PASM. The former corresponds to the diffuse growth pattern and the later to nodular growth pattern on morphology, respectively. The characteristics of cutaneous leiomyosarcoma arising from PASM present as mild cytological atypia, close relationship with hair follicles, higher rate of recurrence and rare metastases. However, this type of tumor can showde differentiation ther recurrence many times . Cutaneous leiomyosarcoma of non-PASM origin presents nodular in appearance, high atipia of tumor cells and has potentials of metastases.