Eberspacher Chiara, Arcieri Stefano, Coletta Enrico, Pontone Stefano, Arcieri Francesco Leone, Mascagni Domenico
Department of Surgery, University of Rome "Sapienza", Rome, Italy.
Department of Surgery, University of Rome "Sapienza", Rome, Italy.
Int J Surg Case Rep. 2023 Sep;110:108674. doi: 10.1016/j.ijscr.2023.108674. Epub 2023 Aug 18.
Malignant peripheral nerve sheath tumor is an aggressive tumor that arises from peripheral nerves. Frequently associated with neurofibromatosis, its common localization is in the extremities, trunk (with paravertebral regions), neck and head. Some cases have been found in the pelvis or uterus. In this case report we illustrate one of the rarest localization of this type of tumor in the ischiorectal fossa, with the full recovery of the patient after surgical excision and radiotherapy.
A 61-year-old woman showed a lump near the anus which was initially diagnosed as a lipoma of the right ischiorectal fossa, by Computed Tomography scan. The tumor was completely removed with a minimal skin incision, and the patient had a complete recovery. Only the pathological examination determined the diagnosis of malignant peripheral nerve sheath tumor, in this unusual localization. In consideration of its high aggressiveness the patient underwent radiotherapy. After more than two years of follow-up there is no sign of recurrence.
In sites far from branches of nerves, malignant peripheral nerve sheath tumors can be considered episodic. Ischiorectal fossa is a rare localization, and the differential diagnosis from benign mesenchymal cell tumors can be challenging. When possible, a biopsy should be performed before surgery.
Surgical excision of tumors in ischiorectal fossa should be always complete, in consideration of possible histological surprise.
恶性外周神经鞘瘤是一种起源于外周神经的侵袭性肿瘤。它常与神经纤维瘤病相关，常见的发生部位在四肢、躯干（包括椎旁区域）、颈部和头部。也有一些病例发生在骨盆或子宫。在本病例报告中，我们展示了这种肿瘤在坐骨直肠窝最罕见的发生部位的一例，患者经手术切除和放疗后完全康复。
一名61岁女性肛门附近出现一个肿块，计算机断层扫描最初诊断为右侧坐骨直肠窝脂肪瘤。通过最小的皮肤切口手术将肿瘤完全切除，患者完全康复。仅通过病理检查才确定了这个不寻常部位的恶性外周神经鞘瘤的诊断。鉴于其高侵袭性，患者接受了放疗。经过两年多的随访，没有复发迹象。
在远离神经分支的部位，恶性外周神经鞘瘤可被视为偶发性的。坐骨直肠窝是一个罕见的发生部位，与良性间充质细胞瘤的鉴别诊断可能具有挑战性。如果可能，手术前应进行活检。
考虑到可能出现的组织学意外情况，坐骨直肠窝肿瘤的手术切除应始终彻底。
