手指に発生した血管平滑筋腫の3例

Angioleiomyoma of the Hand. Report of Three Cases

　稀な手指発生の血管平滑筋腫の3例を報告する．3例ともにほぼ同様に，MRIにて，皮下にT1強調像で低信号，T2強調像で高信号と筋と等信号の混在する腫瘍を認め，T1強調像とT2強調像ともに，低信号の被膜様構造を認めた．MRI所見と病理組織学的所見の対比では，T2強調像で高信号の部分は，血管腔に一致し，T2強調像で等信号の部分は平滑筋線維の増生に，低信号の部分は膠原線維性の被膜に一致していた．MRIにて，結節性腫瘍が皮膚あるいは皮下に存在し，T2強調像で高信号と等信号が混在し，辺縁にT2強調像で低信号を呈するものでは，血管平滑筋腫も考慮すべきと考える．

　We report three rare cases of angioleiomyoma of the hand. We analyzed the MRI findings and compared them with the pathology findings. All masses were hypointense on T1-weighted MRI. T2-weighted MRI showed mixed areas that were hyperintense and isointense to skeletal muscle in all three cases. T1 and T2-weighted MRI revealed a peripheral hypointense rim. The hyperintense areas on the T2-weighted MRI images corresponded to vascular spaces, the isointense areas were related to proliferation of smooth muscle, and the well-defined hypointense peripheral rims on T2-weighted corresponded to fibrous capsules with collagen fiber bundles. Angioleiomyoma should therefore be suspected in patients who present with a mass in the hand located in the skin or subcutaneous tissue and in whom T2-weighted MRI reveals a peripheral hypointense rim and areas that are hyperintense and isointense to skeletal muscle.