Neurofibroma of the stomach: Report of a case

We report herein the case of a 71-year-old-Japanese woman who was admitted to hospital for surgical treatment of a lower abdominal tumor. At laparotomy the tumor was found to be pedunculated and growing extramurally from the greater curvature of the stomach. Thus, a wedge resection of the stomach, including the mass, was performed. The tumor measured about 9×8×7 cm and histological examination of the resected specimen showed that the main elements consisted of wavy, long-spindled cells, which crossed irregularly, indicating that it was palisading negative. Immunohistochemically, the specimen was positive for both S-100 protein and Alcian blue. From these findings, the tumor was histologically diagnosed as a neurofibroma. The patient had an uneventful postoperative course and no signs of recurrence have been recognized in the 3 years since her operation.     

Hemorrhage into a plexiform neurofibroma induced by trauma: a rare complication of von Recklinghausen's disease

A case of hemorrhage into a plexiform neurofibroma of a 53-year-old woman is described. Immediately after trauma to the plexiform neurofibroma on her scalp, she noticed severe headaches and sudden enlargement of the tumor. The tumor continued to enlarge slowly. Her headaches also continued until tumor excision. The specimen taken during surgery surrounded a round cavity about 7 cm in diameter containing coagulated blood. Numerous, old, perivascular hemorrhages around many dilated vessels with extremely thin walls were revealed by histological examination.     

Elevated ankyrin G in a plexiform neurofibroma and neuromas associated with pain

Ankyrin G has recently been shown to be responsible for activation of sodium channels in the developing and regenerating axonal membrane. Via this sodium channel mechanism, elevated ankyrin G levels have been linked with spontaneous ectopic hyperexcitability and thus with pain phenomena in nervous tissue. Ankyrin G, a transmembrane, structural protein of the axon, was examined in four conditions: (a) painful plexiform neurofibroma; (b) painful neuroma; (c) non-painful neuromas; (d) normal nerve. Neurofibroma tissue was obtained from an 18-year old male patient who developed an intensely painful, plexiform neurofibroma of the posterior femoral cutaneous nerve and subsequently underwent surgery. Sample proteins were separated by PAGE and labeled with anti-ankyrin G antibodies in a Western blot procedure. RESULTS: The ankyrin G band density (mug) of protein for the painful neurofibroma was 6014 and was 3557 for the painful neuroma as compared to 3041, 1988 and 606 (mean+/-SD=1878+/-1221) for the three non-painful neuromas. Ankyrin G expression in normal nerves (8 specimens from 7 patients) was comparatively less (mean+/-SD=411+/-339). CONCLUSION: Our results may represent the first evidence for abnormally increased levels of ankyrin G protein with painful neurofibromas. Due to ankyrin G's multifunctional role in the development and remodeling of excitable membranes, it can be hypothesized that the significant increase contributes to the development of hyperexcitable axonal membranes in neurofibromas and potentially other peripheral pain conditions.     

巨大神经纤维瘤的手术切除及瘤体皮肤回植

目的:总结巨大神经纤维瘤的手术切除与切取瘤体皮肤修复创面的经验。方法:对1999年8月～2004年4月收治的7例巨大神经纤维瘤进行回顾性分析。臀部2例,背部2例,腰部1例,上肢1例,下肢1例。面积在36cm×25cm～55cm×38cm,瘤体切除后,反取瘤体皮肤使之成为中厚层皮片,回植创面。结果:术中出血少,回植皮片成活良好,回访6个月～4年以上,皮片生长稳定,外观满意,未见瘤体复发。结论:巨大神经纤维瘤可完整或大部分手术切除,切取的瘤体皮肤回植创面,可取得良好的外观。     

Myxoid change within cellular blue naevi: a diagnostic pitfall

We describe four cases of a distinctive myxoid change located in the centre of cellular blue naevi. Because all the reported lesions were large and were present on pressure-exposed locations, the myxoid change is thought to be caused by pressure together with direct repeated minor tissue trauma.     

Benign peripheral nerve sheath tumors (neurofibromas) of the lacrimal gland

Two patients, a 43-year-old woman and a 62-year-old man, developed benign peripheral nerve sheath tumors (neurofibromas) of the lacrimal gland, in the former case of the deep orbital lobe, and in the latter of the palpebral lobe. A neurogenic tumor was not seriously considered clinically in either case, because of the paucity of previous reports on the occurrence of neural tumors in the lacrimal fossa region. Instead, in the first case a benign mixed tumor was considered the most likely clinical diagnosis, whereas in the second the coexistence of a swelling in the parotid gland raised the possibilities of a lymphoid tumor or a leukemia. Due to unusual light microscopic features, transmission electron microscopy was required to secure unequivocal diagnoses. In the orbital lobe tumor, an encapsulated spindle cell proliferation without nuclear palisading but with focal areas of myxoid change suggested either a cellular benign mixed tumor or a schwannoma. The palpebral lobe lesion displayed a myxoid spindle cell proliferation that had splayed apart the ducts and acinae of the lacrimal gland, to impart the overall appearance of a benign mixed tumor. The ducts, however, were multilaminar rather than possessing the usual double cellular layer seen in classical benign mixed tumors, and the glandular units contained zymogen granules, which are typically not seen in benign mixed tumors. Electron microscopy disclosed in both lesions the presence of interrupted basement membrane material partially surrounding the tumor cells, long spacing collagen (banded basement membrane material), and poorly developed desmosomes, features compatible with a neural tumor. Neither myofilaments, tonofilaments, nor ductal-type granules sometimes observed in benign mixed tumors were discovered. The tumor cells in these cases therefore failed to demonstrate clear-cut Schwann cell characteristics (eg, continuous basement membranes, pseudo-mesaxons, tangles of cell processes), and more closely resembled perineural cells that have been described in ultrastructural studies of peripheral nerve tumors including neurofibromas of other sites.     

Nerve sheath tumors of the sciatic nerve and sacral plexus

Eight patients with sciatic nerve and sacral plexus nerve sheath tumors, seen at Louisiana State University Medical Center in Shreveport, are presented. These cases illustrate the broad spectrum of pathology and modes of presentation of patients with nerve sheath tumors in this region. Patients can be divided into 4 groups. Group I includes subgluteal and/or thigh lesions with a well-defined mass on CT. Group II patients have neuroforaminal enlargement (defined by CT) and usually have radicular leg pain. Patients in group III have intrapelvic tumors with extension into the thigh. They usually have a poorly defined mass on CT. Group IV includes patients that have an intrapelvic mass (usually well defined) with radicular leg pain and/or mass effect. CT scanning proved to be the diagnostic procedure of choice. It delineated the location and extent of the tumor and thus was important in determining resectability. The variable course of these tumors is emphasized. A conservative nonoperative approach should be considered in asymptomatic and/or neurologically stable patients.