Scheithauer, Bernd W.

Object Adipose lesions of nerve are rare and poorly understood. Their current classification, although not universally accepted, generally includes lipomatosis of nerve with or without localized macrodactyly, and intra- as well as extraneural lipoma. The authors believe that the spectrum of these lesions and their interrelationships are not currently appreciated. They propose an adaptation to the existing framework to illustrate the expanding spectrum of adipose lesions of nerve by considering lipomatosis and lipoma singly or in combination. Methods Fourteen representative cases are presented to demonstrate not only the intraneural and extraneural examples of lipomatosis and lipoma, but also their anatomical combinations. Results Based on the cases presented and a careful literature review, a conceptual approach to the classification of adipose lesions of nerve is generated. This approach incorporates the 2 essential lesions, lipomatosis of nerve and lipoma, in both their intra- and extraneural forms. This permits expansion to encompass combinations. Conclusions To press the concept that adipose tumors of nerve are a broad but interrelated spectrum of lesions, the authors propose modification of the present classification system. This approach provides an orderly platform for progress, reflects understanding of these interrelated lesions, and facilitates optimal treatment by distinguishing resectable from nonresectable components.

Object Neuromuscular choristoma (NMC) is a rare peripheral nerve lesion in which mature skeletal muscle fibers lie within the nerve and its fascicles. Given limited follow-up, its natural history is poorly understood. The occurrence of aggressive fibromatosis in one of the authors' patients and its occurrence in reported cases suggests an etiological relationship between the 2 lesions. This study attempts to explain the association and its frequency. Methods All cases of NMCs seen in consultation or treated at the Mayo Clinic were identified. Demographic and clinical data were reviewed in cases with coexistent aggressive fibromatosis. Pathology and neuroimaging studies were reexamined. In addition, an extensive literature review was performed to explore the association of NMC with aggressive fibromatosis, with special attention given to pathological and imaging characteristics and the development of aggressive fibromatosis. Results The authors identified 10 patients with a diagnosis of NMC who were treated at the Mayo Clinic between 1992 and 2010. Four of 5 with adequate follow-up had developed a definite or suspected aggressive fibromatosis. A review of the initial pathological specimens in these cases revealed no evidence of fibromatosis, but all of the lesions exhibited accompanying hypocellular collagenous tissue. On MR images, all cases showed areas of low signal intensity, which significantly differed from muscle, nerve, and NMC components. On available serial MR imaging studies, aggressive fibromatosis seemed to originate in such lower-intensity regions. In the 18 previously reported cases of NMC, 5 patients developed recurrent masses diagnosed as either definite (2 cases) or possible (3 cases) fibromatosis. Review of the published imaging studies in these cases suggests the presence of lower intensity areas similar to those observed in the 10 patients treated at the Mayo Clinic. Conclusions This study confirms that the development of aggressive fibromatosis in patients with NMC has been underreported. A direct relationship between the NMC and the development of aggressive fibromatosis is suggested by pathological and neuroimaging evidence.

Abstract We studied the status of estrogen (ER) and progesterone (PR) receptors in meningiomas removed from 52 patients, comparing dextran-coated charcoal (DCC), nuclear binding (NB), and immunoperoxidase (IP) assays. Each of the assays was performed independently by investigators well-experienced with these assays. The NB assay is a new assay that measures functional steroid receptors—that is, the activation of the receptor and its binding to the nucleus. The assay is very sensitive and requires a relatively small amount of tissue as compared with the DCC assay. In agreement with data from other studies, PR were detected in most meningiomas by all 3 methods: in 69% of the cases by NB, in 76% by DCC, and in 89% by IP. ER were detected in only a few cases: in 33% by NB, in 2% by DCC, and in none by the IP assay. The agreement for PR sites was 62% for all 3 assays, it was 66% between the NB and DCC assays, 67% between the NB and IP assays, and 86% between the DCC and IP assays. Of 26 cases that were positive by the DCC assay, 6 (23%) were negative by NB. The overall agreement for all three ER assays was 65%. The data suggest that the majority of meningiomas contain high-affinity receptors for progesterone, that estrogen receptors are present in only a few meningiomas, and that some of these estrogen and progesterone receptors appear to be functional.

Abstract Eight surgical and one autopsy specimen of pituitary adenomas (six cases of Cushing's disease, two of Nelson's syndrome. and one of hypopituitarism) were studied by histochemical, immunohistocytological, and ultrastructural methods. Eight tumors showed the characteristic histochemical profile of corticotroph adenoma—amphophilic to basophilic, and periodic acid-Schiff-positive to some extent. In all tumors, immunohistochemical studies revealed adrenocorticotropic hormone (ACTH) and à-subunit in the cytoplasm of some adenoma cells. By electron microscopy, seven tumors were found to be monomorphous; six were typical corticotroph adenomas and one was a subtype II silent corticotroph adenoma. One unique lesion was bimorphous—i.e., composed of corticotrophs as well as cells resembling glycoprotein cells. Immunoelectron microscopy by the double-labeling immunogold technique, performed on one corticotroph adenoma, demonstrated the presence of ACTH and à-subunit not only within the same adenoma cells but also within the same secretory granules. The cytogenesis of ACTH à-subunit tumors, a rare form of plurihormonal adenoma. remains to be elucidated. The duration of disease associated with these tumors exceeded the duration in patients with ordinary corticotroph adenomas. Given the low frequency with which increases in serum à-subunit are detectable in patients with such tumors—13% in this series—hormone production is not recognized at preoperative evaluation.

Abstract Fibromatoses are uncommon infiltrative lesions affecting musculoaponeurotic structures, most often of the limbs and trunk. Lesions involving the cranial cavity are rare and require the same aggressive surgical management as elsewhere in the body. This case illustrates their clinical and neuroradiological features and underscores the necessity for aggressive resection to avoid recurrence. The literature is reviewed. (Neurosurgery 29:123-126, 1991)

Abstract A unique gliomesenchymal neoplasm, consisting of a subependymoma, a form of low-grade glioma, and a rhabdomyosarcoma, is described. It arose and recurred in the brain stem of a 52-year-old man. Immunohistochemical studies demonstrated the presence of a neuroectodermal marker S-100 protein within some sarcoma cells. The occurrence of this rare tumor supports the concept that striated muscle may derive from a neuroectodermal precursor lesion.

Abstract Forty-four cases of meningeal hemangiopericytoma that were treated between 1938 and 1987 are reviewed. Fifty-five percent of these tumors occurred in men. The average age of the patients at diagnosis was 42 years. The average duration of preoperative symptoms was 11 months. Symptoms were related to tumor location, which was similar to that of meningioma. The operative mortality was 9% overall, and has been zero since 1974 (18 patients). The average time before the first recurrence was 47 months, with the recurrence rates at 1, 5, and 10 years after surgery being 15, 65, and 76%, respectively. Ten patients have developed extraneural metastasis, mostly to lung and bone, at an average of 99 months after the first operation. The 10- and 15-year rates of metastasis were 33 and 64%, respectively. The average survival period has been 84 months, with survival rates at 5, 10, and 15 years after surgery of 67, 40, and 23%, respectively. The histological diagnosis of the tumor was not related to survival or recurrence and did not change with recurrence. Tentorial and posterior fossa tumors tended to be more lethal. Total tumor resection favorably affected recurrence and survival, as opposed to subtotal resection. Metastasis adversely affected survival, and was followed by death at an average of 24 months after its diagnosis. Radiation therapy after the first operation extended the average time before first recurrence from 34 to 75 months, and extended survival from 62 to 92 months.

The present study was designed to determine if the noncompetitive excitatory amino acid antagonist, dizocilpine maleate, when administered after a 17 min period of complete cerebral ischemia in primates, would improve postischemic neurologic function and hippocampal histopathologic outcome when compared to placebo-treated animals. Ten pigtail monkeys were anesthetized and subjected to complete cerebral ischemia using an established neck tourniquet model. Five minutes postischemia, five monkeys received dizocilpine 300 μg/kg i.v. over 5 min, followed by an infusion of 150 μg/kg/h for 10 h. This produced plasma levels of the drug in excess of 30 ng/ml for the duration of the infusion. An additional five monkeys were treated with an identical volume of saline placebo. All monkeys received intensive care for the initial 24 to 48 h postischemia. At 96 h postischemia, there was no significant difference in neurologic function between the two groups ( p = 0.53, with the placebo group having the numerically better outcome). There also was no significant difference between hippocampal histopathology scores between dizocilpine and placebo-treated monkeys. The authors conclude that dizocilpine is not an efficacious therapy in the treatment of neurologic injury that occurs following complete cerebral ischemia in this primate model.