Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
Am J Surg Pathol. 2011 Apr;35(4):599-607. doi: 10.1097/PAS.0b013e31820e6093.
Atypical or mitotically active dermal smooth muscle neoplasms are uncommon lesions, which are most often termed "cutaneous leiomyosarcoma," although preexisting-mostly small-series suggest a low risk of aggressive behavior. To further investigate these tumors, 84 cases from consultation and institutional files were analyzed for pathologic and clinical characteristics. There was a striking male-to-female preponderance (4.3:1), with a mean age of 56 years (range, 6 to 82y). Nine patients had a history of malignancies (6 of the skin). Tumors measured 1.3 cm on average and were predominantly located on the trunk (32) and lower extremities (30). Histologically, all tumors were confined to the dermis or showed only very superficial, focal subcutaneous extension. The majority showed an infiltrative growth pattern with fascicles of atypical eosinophilic spindle cells ramifying between dermal collagen fibers. Primary tumors showed a mean mitotic rate of 4.7/10 high-power fields. By the Fédération Nationale des Centres de Lutte Contre le Cancer grading system, 97% of primary tumors were grade I lesions, with only 3% showing necrosis. All tumors were immunopositive for smooth muscle actin; 98% expressed desmin, 90% caldesmon, and 45% pankeratin (usually focal). Follow-up in 52 cases (mean, 51 mo) showed no metastases or tumor-related deaths. Eighteen tumors showed local recurrence at a mean interval of 43 months; 12 of the recurrent lesions showed positive margins in the primary excision and 1 showed margins <0.2 cm. Margin status was not available for the other 5 cases, which recurred locally. Recurrent tumors showed, on average, 13.7 mitoses/10 high-power fields. Of recurrences, 47% were grade I lesions, 35% were grade II, and 18% were grade III, and 28% showed necrosis. The primary excision of tumors, which later recurred, showed no difference in grade, presence of necrosis, or mitotic rate, compared with those that did not recur; there were no discernible clinical differences either. In summary, these tumors, when confined to the dermis or showing only minimal subcutaneous involvement, seem to carry no evident risk of metastasis; hence, the designation "sarcoma" is inappropriate. Margin status is the most important predictor of recurrence. On excision with clear margins, the risk of local recurrence is very low. Hence, we propose the term "atypical intradermal smooth muscle neoplasm" as being more appropriate.
非典型或有丝分裂活性的真皮平滑肌肿瘤是不常见的病变，通常被称为“皮肤平滑肌肉瘤”，尽管大多数为小系列研究表明其侵袭性行为风险较低。为了进一步研究这些肿瘤，对咨询和机构档案中的 84 例病例进行了病理和临床特征分析。存在明显的男性对女性的优势（4.3:1），平均年龄为 56 岁（范围为 6 至 82 岁）。9 例患者有恶性肿瘤病史（6 例为皮肤）。肿瘤平均直径为 1.3cm，主要位于躯干（32 例）和下肢（30 例）。组织学上，所有肿瘤均局限于真皮或仅表现出非常浅表的、局灶性的皮下延伸。大多数肿瘤呈浸润性生长模式，有异型嗜酸性梭形细胞束在真皮胶原纤维之间分支。原发性肿瘤的平均有丝分裂率为 4.7/10 高倍视野。根据法国抗癌中心联合会（Fédération Nationale des Centres de Lutte Contre le Cancer）分级系统，97%的原发性肿瘤为 I 级病变，仅 3%有坏死。所有肿瘤均对平滑肌肌动蛋白呈免疫阳性；98%表达结蛋白，90%表达钙调蛋白，45%表达细胞角蛋白（通常为局灶性）。在 52 例病例（平均随访时间为 51 个月）中，无转移或肿瘤相关死亡。18 例肿瘤在平均间隔 43 个月时出现局部复发；12 例复发性病变在原发性切除时切缘阳性，1 例切缘<0.2cm。另外 5 例复发性病变的切缘状态无法获得，这些病变局部复发。复发性肿瘤的有丝分裂率平均为 13.7/10 高倍视野。复发性肿瘤中，47%为 I 级病变，35%为 II 级病变，18%为 III 级病变，28%有坏死。与未复发的肿瘤相比，后来复发的肿瘤在分级、坏死存在或有丝分裂率方面没有差异；也没有明显的临床差异。总之，这些肿瘤局限于真皮或仅表现出最小的皮下累及，似乎没有明显的转移风险；因此，“肉瘤”的命名并不合适。切缘状态是复发的最重要预测因素。在有明确切缘的切除时，局部复发的风险非常低。因此，我们提出“非典型真皮平滑肌肿瘤”这一术语更为合适。
