71/75. Neurofibromatosis masquerading as monoarticular juvenile arthritis. A 3-yr-old boy presented with a monoarthritis. Persistence of the condition and some unusual features led to re-evaluation of the original investigations, when a diagnosis of extensive plexiform neurofibroma involving his right leg was made. This previously unreported presentation of neurofibromatosis is discussed. ( info) |
72/75. Clonal origin of tumor cells in a plexiform neurofibroma with LOH in NF1 intron 38 and in dermal neurofibromas without LOH of the NF1 gene. LOH at the NF1 locus was investigated in 38 neurofibromas of 26 NF1 patients. Only in one of these tumors LOH was observed. In this plexiform neurofibroma of a NF1 patient with a constitutional one base-pair insertion in NF1 exon 4b, a non-random X-inactivation pattern was found, strongly suggesting a clonal origin of the tumor cells. The analysis of X-inactivation patterns allowed the classification of some of the other neurofibromas with regard to the detectability of clonal LOH. In 3 of 6 neurofibromas without LOH amenable to this analysis, a comparable X-inactivation pattern was found in constitutional and neurofibroma derived dna. A clonal LOH would not have been detected in these tumors. However, we observed a nonrandom pattern in 3 of the 6 neurofibromas, suggesting a clonal origin of the tumor cells. LOH was not detected in these tumors, but could, however, have occurred by mutational events below the level of large somatic deletions, loss of a whole chromosome 17 or somatic recombination. ( info) |
73/75. Principles in management of complex pediatric genitourinary plexiform neurofibroma. Neurofibromatosis is a hamartomatous disorder of neural crest derivation characterized by cutaneous pigmentation and tumor formation in various tissues. Visceral involvement is typically insidious, progressive, and difficult to treat. Plexiform neurofibroma of the urinary tract is rare. Involvement of nearly every genitourinary structure by these lesions has been reported, with the bladder being most commonly involved. In part due to the small number of patients seen at any one institution and the highly variable location and extent of this disease process, a plan for management of individuals with genitourinary neurofibromatosis has not been proposed. In an attempt to define specific goals in treatment of such patients, we reviewed our population of 260 pediatric patients with type 1 neurofibromatosis. We present our series of 5 patients with complex genitourinary lesions and describe specific management principles. ( info) |
74/75. Multiple idiopathic mucosal neuromas: a minor form of multiple endocrine neoplasia type 2b or a new entity? multiple endocrine neoplasia type 2b (MEN 2B) is a rare autosomal dominant process characterized by medullary thyroid carcinoma, pheochromocytoma, and mucosal neuromas. A point mutation at codon 918 of the RET protooncogene has been observed in approximately 90% of patients and families with MEN 2B. Mucosal neuromas are the most consistent and distinctive feature (100% of patients) of MEN 2B and are considered pathognomonic. We describe a 35-year-old woman with mucosal neuromas of the lower lip and tongue that appeared in early childhood. Examination did not reveal other abnormalities. After a follow-up of more than 22 years with periodic clinical, biochemical, and radiologic studies, no evidence of MEN 2B has been detected. Analysis of the RET protooncogene exons 10, 11, and 16 did not demonstrate point mutation in the MEN 2B region (M918T). ( info) |
75/75. Massive plexiform neurofibroma in the orbit in a child with von Recklinghausen's disease. We report a case of orbital plexiform neurofibroma presenting in a 10-year-old boy with von Recklinghausen's neurofibromatosis. The patient had shown a slow enlargement of exophthalmos of the right eye present since birth, together with multiple cafe au lait spots on the skin of the trunk. Magnetic resonance (MR) images revealed diffuse and irregular nodular involvement of the retrobulbar nerves within the muscle cone, which was confirmed at the surgery. The tumour extended into the ipsilateral cavernous sinus. We discuss the MR findings as pathognomonic signs of this rare orbital tumour, including its multinodular nature among dispersed intraconal fat tissue, location around the optic nerve, extension through the superior orbital fissure into the cavernous sinus and association with von Recklinghausen disease. ( info) |