Takeyama Junji, Hayashi Toshiaki, Sanada Takehiko, Shimanuki Yoshihisa, Saito Mioko, Shirane Reizo
Department of Pathology, Miyagi Children's Hospital, Sendai, Japan.
J Cutan Pathol. 2005 Apr;32(4):310-3. doi: 10.1111/j.0303-6987.2005.00312.x.
A 1-year-6-month-old girl presented with a subcutaneous tumor of the forehead, which had developed since birth. The preoperative examinations showed nasofrontal bone defect with meningocele and subcutaneous tumor with cyst. The patient underwent excision of the tumor and reconstruction of the bone defect. Histologically, the skin tumor exhibited disordered arrangement of striated muscle fibers among normal dermal components, and the cyst was lined by cornified epithelium with a few hair adnexa and contained lamellated keratin. These findings were consistent with rhabdomyomatous mesenchymal hamartoma (RMH) and dermoid cyst. This is an interesting case of RMH co-existing with nasofrontal meningocele and dermoid cyst in the same area. We suggest embryologic errors as a possible etiology, which is incomplete dysjunction of the neural ectoderm from the cutaneous ectoderm. Failure of insertion of mesoderm between the ectoderms caused the bone defect and the disordered proliferation and differentiation of mesoderm-derived tissue, leading to formation of hamartoma.
一名1岁6个月大的女童因自出生起就出现的前额皮下肿瘤前来就诊。术前检查显示鼻额骨缺损伴脑膜膨出以及皮下肿瘤伴囊肿。患者接受了肿瘤切除及骨缺损修复手术。组织学检查显示，皮肤肿瘤在正常真皮成分中呈现出横纹肌纤维排列紊乱，囊肿内衬角化上皮，有一些毛囊附属器，并含有板层状角蛋白。这些发现符合横纹肌瘤样间叶性错构瘤（RMH）和皮样囊肿。这是一例RMH与鼻额部脑膜膨出及皮样囊肿在同一区域并存的有趣病例。我们认为胚胎学错误可能是病因，即神经外胚层与皮肤外胚层不完全分离。中胚层未能插入外胚层之间导致了骨缺损以及中胚层来源组织的无序增殖和分化，进而形成错构瘤。
