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S W Weiss

Publications and source records attributed to S W Weiss.

At least 19 recordsLinked to original sources
PubMed1998

NMDAR1 glutamate receptor subunit isoforms in neostriatal, neocortical, and hippocampal nitric oxide synthase neurons.

Nitric oxide (NO), an unconventional and diffusible neurotransmitter, is synthesized by nitric oxide synthase (NOS). NMDA glutamate receptors are potent regulators of NO synthesis. We have used dual-label immunofluorescence and confocal microscopy to examine forebrain neurons in the rat that contain high levels of neuronal NOS (nNOS) for the presence of the NMDAR1 receptor subunit protein and regions of this protein encoded by three alternative spliced segments of the NMDAR1 mRNA: N1, C1, and C2. In the neostriatum, neocortex, and hippocampus, nNOS-labeled neurons exhibit strong NMDAR1 immunoreactivity (-ir). In all three of these regions, nNOS-positive neurons are characterized by the absence of immunoreactivity for the C1 segment of NMDAR1, whereas C1-ir is abundant in most nNOS-negative neurons. In addition, nNOS-ir neurons exhibit selective staining for the alternative C2' terminus of NMDAR1 that is produced when the C2 segment is absent. These results demonstrate directly that neurons with abundant nNOS-ir contain NMDAR1 receptor subunit proteins and that the NMDAR1 isoforms present in these cells differ from those of most other neurons in these regions. The distinct NMDA receptor phenotype of these nNOS-positive neurons is likely to contribute to both the physiological regulation of NO release by glutamate as well as to NO-mediated excitotoxic injury.

Animals↗
PubMed1998

Immunohistochemical localization of metabotropic glutamate receptors mGluR1a and mGluR2/3 in the rat basal ganglia.

Metabotropic glutamate receptors (mGluRs), which couple glutamate to second messengers, have important roles in the regulation of movement by the basal ganglia. We used two polyclonal antisera to mGluR1a and mGluR2/3 and confocal laser microscopy to investigate the localization of these receptors in the basal ganglia of the rat. The mGluRs were visualized in combination with an antibody to tyrosine hydroxylase (TH), an antibody to microtubule-associated protein 2 (MAP2, a dendritic marker), or SV2 (an antibody to a protein associated with presynaptic terminals). In the neostriatum, punctate mGluR1a immunoreactivity (ir) was present in the neuropil. This staining did not colocalize with MAP2-ir or SV2-ir and was not altered by decortication or unilateral 6-hydroxydopamine (6-OHDA) lesions. In the globus pallidus and substantia nigra pars reticulata, however, mGluR1a-ir was tightly clustered along large MAP2-ir dendrites. In contrast to the variations in mGluR1a-ir staining, similar punctate neuropil mGluR2/3-ir staining was observed within all basal ganglia structures. In the neostriatum, these puncta were abundant; unlike mGluR1a, many mGluR2/3-ir puncta colocalized with SV2-ir, and striatal mGluR2/3-ir puncta were markedly reduced in number after decortication. Neither mGluR1a-ir nor mGluR2/3-ir could be detected in TH-ir soma within substantia nigra pars compacta, or in TH-ir striatal terminals. Overall, our observations suggest that mGluR1a and mGluR2/3 receptors have distinct cellular localizations in different components of the basal ganglia circuitry and are likely to subserve distinct functions. Our data support the presence of mGluR2/3 on the terminals of corticostriatal afferents, where they may regulate glutamate release. In contrast, mGluR1a appears to be a postsynaptic receptor of neurons in the neostriatum, globus pallidus, and substantia nigra pars reticulata.

Animals↗
PubMed1998

Multiple spindle cell lipomas: a report of 7 familial and 11 nonfamilial cases.

Spindle cell lipoma, a variant of a benign lipoma, usually occurs as a solitary, subcutaneous, circumscribed lesion in the posterior back, neck, or shoulders of older men. Multiple lesions are exceedingly rare. To our knowledge, there have been no previous series reported of patients with multiple subcutaneous spindle cell lipomas. We examine the clinicopathologic findings of a group of patients with multiple spindle cell lipomas, including seven with a familial occurrence of this disease. The Soft Tissue Registry of the Armed Forces Institute of Pathology and the consultation files of one of the authors (S.W.W.) from the Department of Pathology at the University of Michigan were searched for patients with multiple spindle cell lipomas. All patients' records, clinical history, and pathology were reviewed. All patients had a minimum of two tumors that met strict morphologic criteria for spindle cell lipoma. Pleomorphic cells, typical of pleomorphic lipoma, were observed in some cases and were acceptable as part of the spectrum of spindle cell lipomas. Associated lesions, family history, ethnic background, daily habits, and natural progression of disease were recorded and compared. Eighteen patients in our files met the criteria for multiple spindle cell lipomas; 4 of the 18 patients were from the same family. Three additional patients had a family history of multiple spindle cell lipomas. The ratio of patients with multiple spindle cell lipomas to all patients with spindle cell lipoma in the two consultation files was 0.5 and 3%, respectively. All of the patients in our study were male; three had a family history of females with less severe disease (fewer and smaller spindle cell lipomas); however, no material from these female patients was available for review. All but four patients presented in their sixth through eighth decades of life; yet, several older patients stated that their first lesion occurred in their fifth decade. Patients had between 2 and >220 lesions, which usually commenced on the posterior neck or back, commonly followed by additional bilateral lesions on the shoulders and upper torso. The natural history of this disease revealed development of multicentric lesions over several years, for both familial and nonfamilial cases. The tumors became more cellular as the disease progressed, often with features of pleomorphic lipoma; however, no patients developed spindle cell liposarcoma. Multiple spindle cell lipomas are rare. The clinical presentation may mimic Madelung's disease (symmetrical lipomatosis). As mentioned above, some cases are familial. Genetic predisposition must be further examined. There appears to be no common ethnic background, environmental exposure, medical condition, or syndrome of associated lesions with multiple spindle cell lipomas.

Adult↗
PubMed1997

Dedifferentiated liposarcoma: a clinicopathological analysis of 155 cases with a proposal for an expanded definition of dedifferentiation.

We studied 155 cases of dedifferentiated liposarcoma to define its clinicopathologic features and behavior, in particular how the extent and grade of dedifferentiation affected outcome. Tumors occurred in late adult life (median, 61.5 years: range, 21-92 years), most commonly in the retroperitoneum (106 cases), extremities and trunk (32 cases), and scrotum/spermatic cord (13 cases). The majority of dedifferentiated liposarcomas presented as de novo lesions, whereas the remainder developed as a late complication of a preexisting well-differentiated liposarcoma after an average interval of 7.7 years. At the time of presentation, most of the dedifferentiated liposarcomas displayed extensive areas of high-grade dedifferentiation resembling malignant fibrous histiocytoma or high-grade fibrosarcoma, whereas a minority contained only areas of low-grade dedifferentiation resembling fibromatosis or well-differentiated fibrosarcoma. Divergent myosarcomatous or osteosarcomatous differentiation was observed focally in six cases. The behavior of dedifferentiated liposarcomas was that of a high-grade sarcoma with a local recurrence rate of 41%, a metastatic rate of 17%, and disease-related mortality of 28%. The most important prognostic factor was location in that retroperitoneal tumors had significantly worse survival than those in other sites. Tumors were divided into those having less than or those with more than 25% dedifferentiation, and dedifferentiated zones were classified into low grade or high grade. Neither low-grade dedifferentiation nor a low percentage of dedifferentiation was associated with an improved outcome for the tumors examined in this study; however, in no cases was the absolute size of the dedifferentiated focus <2 cm. Therefore, this study did not determine a minimum, or threshold, amount of dedifferentiation below which outcome was more favorable. The behavior of liposarcomas in which the dedifferentiated component was entirely low grade was more similar to that of traditional dedifferentiated liposarcoma than to that of well-dedifferentiated liposarcoma. Our study supports the expansion of the definition of dedifferentiated liposarcoma to include tumors with low-grade dedifferentiation and also suggests that low-grade dedifferentiation represents a precursor lesion of high-grade dedifferentiation.

Adult↗
PubMed1997

Hyalinizing spindle cell tumor with giant rosettes: a distinctive tumor closely resembling low-grade fibromyxoid sarcoma.

We report the findings of 19 cases of a previously undescribed spindle cell tumor of soft tissues that resembles a low-grade fibromyxoid sarcoma but contains distinctive rosettelike structures. The tumors occurred principally as a painless, slowly growing, deeply situated mass of the proximal extremities in young to middle-aged adults (age range 14-65 years; mean 38). Although grossly circumscribed, the tumors had infiltrative borders microscopically and were composed of bland spindled cells situated in a hyalinized to myxoid stroma. The most characteristic feature of the tumor was scattered large rosettelike structures that often merged with serpinginous areas of dense hyalinization. The rosettes consisted of a central collagen core surrounded by a rim of rounded cells morphologically and immunophenotypically different from the cells of the spindled stroma. These cells expressed a number of antigens, including S-100 protein, neuron-specific enolase, and leu 22, in contrast to the stroma, which usually lacked these antigens. Of the 12 patients with available follow-up information, one patient treated with simple excision clinically developed local recurrence of the tumor 20 months after initial biopsy. No other recurrences were reported during the limited follow-up period, and no patient developed metastatic disease. However, the favorable prognosis of the patients in our series to date may relate to the limited follow-up period (approximately 3 years), as well as initial treatment by wide excision in nearly half of the patients. We regard the hyalinizing spindle cell tumor with giant rosettes as a distinctive type of low-grade fibroblastic tumor that with time may prove to behave similar to a low-grade fibromyxoid sarcoma and, hence, to represent an unusual variant thereof.

Actins↗
PubMed1997

Inflammatory malignant fibrous histiocytoma: distinction from Hodgkin's disease and non-Hodgkin's lymphoma by a panel of leukocyte markers.

Inflammatory malignant fibrous histiocytoma (IMFH), consisting of large, atypical histiocyte-like cells set amidst an inflammatory backdrop of eosinophils, neutrophils, lymphocytes, and xanthoma cells, can be difficult to distinguish from Hodgkin's disease and non-Hodgkin's lymphoma, particularly of the Ki-1 anaplastic large-cell type in small biopsy specimens. This problem is becoming more prevalent with the use of needle biopsies guided by computed tomography for definitive diagnosis. For this reason, we studied the expression of a battery of leukocyte markers in IMFH to evaluate whether they could serve as an independently reliable means of distinguishing amongst the three neoplasms. Eight examples of histologically typical IMFH were stained with a number of leukocyte markers that included CD30 (BerH2), CD15 (leuM1), CD45/ CD45RB (2B11,PD7/26/16), CD43 (leu 22), CD45RO (A6), CD20 (L26), and CD68 (KPI). The large anaplastic tumor cells within IMFH consistently lacked CD30, CD15, CD45/CD45RB, CD43, CD45RO, and CD20. In one case, the anaplastic cells expressed CD68. Benign histiocytes within IMFH expressed CD68 and displayed variable expression of CD15, CD45/CD45RB, and CD43. The reactive lymphocytes consisted mostly of scattered small T cells with a few B cells, mainly within lymphoid aggregates. We conclude that the immunophenotypic profile of the anaplastic cells in IMFH (lack of CD15, CD30, CD43, CD45/CD45RB, CD45RO, CD20) differs from most cases of Hodgkin's disease (ICD30+, CD15+/-) and from Ki-1 anaplastic large cell lymphoma (CD30+, CD45/CD45RB+/-, CD43+/-, CD45RO+/-, CD20-/+). Immunohistochemistry is an important diagnostic adjunct, provided care is taken to exclude benign histiocytes and inflammatory cells from consideration.

Adult↗
PubMed1996

Crystal-storing histiocytosis associated with lymphoplasmacytic lymphoma mimicking Weber-Christian disease: immunohistochemical, ultrastructural, and gene-rearrangement studies.

A case of crystal-storing histiocytosis associated with lymphoplasmacytic lymphoma is presented. Unlike previous cases, this patient presented with signs and symptoms suggestive of Weber-Christian disease. Biopsy of subcutaneous nodules showed numerous deposits of crystal-storing histiocytes with lymphoplasmacytic cells, the latter exhibiting light chain restriction (lambda-chain) with a predominance of immunoglobulin (Ig)G heavy chain. Polymerase chain reaction (PCR) analysis of CDR-II* region of the immunoglobulin heavy chain locus confirmed monoclonality of the lymphoplasmacytic cells in the nodule. Electron microscopy showed polygonal-shaped amorphous crystals, characteristic of immunoglobulin in the histiocytic cells. Crystal-storing histiocytosis should be examined by immunohistochemical and DNA analysis to confirm or exclude the possibility of lymphoplasmacytic lymphoma.

Adult↗
PubMed1996

Pleomorphic hyalinizing angiectatic tumor of soft parts. A low-grade neoplasm resembling neurilemoma.

Fourteen examples of an unusual mesenchymal tumor characterized by sheets and fascicles of mitotically inactive, hemosiderin-stippled, spindled, and pleomorphic cells, situated around an angiectatic vasculature, are described. The 14 tumours developed in eight women and six men (aged 32-83 years) and ranged in size from 2.3 to 8 cm. Eleven cases presented in the subcutaneous tissues, of which eight were located in the lower extremity. All featured prominent clusters of thin-walled ectatic vessels surrounded by perivascular hyaline material representing a combination of fibrin and collagen. In three cases the perivascular hyalinization was so extensive that it constituted more than half of the total tumor area. The tumor cells were similar to those of malignant fibrous hystiocytoma but differed from them by the presence of prominent intranuclear cytoplasmic inclusions, the extreme scarcity of mitotic figures, and the occasional presence of CD-34 expression. These tumors also shared several features with neurilemomas, such as their unusual vasculature, intranuclear cytoplasmic inclusions, lack of mitotic figures, and abundance of mast cells. They could be distinguished from neurilemomas, however, by the usual presence of infiltrative margins and the absence of S-100 protein. Follow-up information on eight patients (6 months to 25 years) indicated recurrences in four cases, with one of the three patients experiencing numerous recurrences over a 25-year period. No patient has developed metastases, however. We suggest that this tumor is a low-grade sarcoma of uncertain lineage in which the vascular changes are, in part, reflective of its slow growth.

Adult↗
PubMed1996

Cutaneous malignant melanotic neurocristic tumors arising in neurocristic hamartomas. A melanocytic tumor morphologically and biologically distinct from common melanoma.

Cutaneous neurocristic hamartomas (CNH) are pigmented lesions of neural crest origin that involve the skin and superficial soft tissue. They consist of a complex proliferation of nevomelanocytes, schwann cells, and pigmented dendritic and spindled cells. Malignancies can arise within the lesions, but few studies have dealt with this issue. We studied seven cases of CNH in which malignancy supervened. They included four congenital and three acquired lesions that involved the head and neck (five cases) or back (two cases) in patients aged from 11 to 67 (mean, 32) years. Malignant tumors developed 15 to 67 (mean, 32) years after identification of the pigmented lesion in the congenital CNH and after 1 to 6 (mean 3.5) years in the acquired CNH. The malignant tumors had a deep intradermal or subcutaneous origin and lacked a junctional component. Most were circumscribed, multinodular, melanin-containing tumors composed of bland, small, rounded to spindled cells, focally displaying a trabecular or nested growth pattern. Nuclear palisading and perivascular pseudorosettes were present in several tumors. In two examples, the neoplasm consisted predominantly of large pleomorphic epithelioid cells. Tumors contained immunoreactive S-100 protein (all of seven cases), a melanoma-associated antigen (HMB-45)( five of six cases, neuron-specific enolase (five of seven cases) and vimentin (six of six cases). The four patients with congenital lesions tended to have multiple recurrences and died of disease after 2 to 20 (mean, 9) years, three with metastases, one with direct invasion of the posterior fossa. The three patients with acquired lesions are alive after 1 to 5 years two with persistent disease. In contrast to common melanomas, these tumors have a propensity to recur as bulky nodules and to metastasize after many years or decades. Because these tumors exhibit melanocytic differentiation and arise in hamartomatous lesions composed of neural crest derivatives, we have designated them cutaneous malignant melanotic neurocristic tumors.

Adult↗
PubMed1996

Spindle cell hemangioendothelioma. An analysis of 78 cases with reassessment of its pathogenesis and biologic behavior.

Seventy-eight cases of spindle cell hemangioendothelioma (SCH) were studied to reevaluate its pathogenesis and determine its long-term behavior. Most of the original findings were confirmed by this study. The tumor occurred at all ages (8-78 years; median, 32 years; mean, 34 years). Males and females were equally affected. The tumor developed as a superficially located mass of the distal extremities (upper, 32 cases; lower, 30 cases). Four patients (5%) also had Maffucci's syndrome. The lesions were circumscribed red-brown masses occasionally containing phleboliths that consisted of cavernous blood spaces alternating with cellular areas consisting of collapsed vascular spaces separated by spindled fibroblastic cells. Often the endothelium lining the collapsed blood spaces appeared epithelioid with cytoplasmic vacuolization. The spindled fibroblastic cells lacked significant atypia and had at most a low level of mitotic activity. As a significant departure from what was originally reported, more than half of these cases (58%) were partially or completely intravascular. The vein containing the tumor often had an irregularly attenuated wall with small intimal herniations and intimal papillae traversing the lumen. Similar intimal changes in adjacent vessels suggest that SCH grows as a multifocal or contiguous process within vessels. Follow-up information was obtained in 40 cases, ranging from 1 month to 40 years (mean, 5.4 years). Despite conservative excisions in most patients (simple excision, 83%; wide local excision, 13%; amputation, 2%), prognosis was excellent. Fifty-eight percent experienced recurrences, but no patient developed metastasis and no patient died of the direct effects of the tumor, although one patient with Maffucci's syndrome developed a concurrent angiosarcoma. We conclude that SCH is a primary benign vascular neoplasm or malformation similar to angiomatosis in which alterations in blood flow might explain some of the secondary features. Areas of diminished blood flow result in vascular collapse with formation of the "cellular" zones, and areas of vascular engorgement with stasis promote thrombosis and organization. Local "recurrences" probably represent contiguous spread along or multifocal involvement of a vessel. Because there is no evidence that this lesion has metastatic potential, we suggest that the lesion be designated spindle cell hemangioma for solitary lesions and spindle cell hemangiomatosis for multifocal lesions.

Adolescent↗
PubMed1996

Lipomatous tumors.

Lipomatous tumors are a common group of mesenchymal lesions. Over the years the major changes in the classification of lipomatous tumors have included the addition of several new variants of lipoma, the use of the term atypical lipoma for well differentiated liposarcoma of the subcutaneous tissue, and recognition of the entity dedifferentiated liposarcoma. Lipomas, the most common lipomatous tumor, account for nearly one-half of all benign lesions. In their typical form they seldom present diagnostic problems for the pathologist. However, lipomas occurring in deep locations (e.g., intramuscular lipoma, perineural lipoma) or those having unusual features (e.g., chondroid lipoma, lipoma with hibernoma, cellular angiolipoma, spindle cell/pleomorphic lipoma) may be confused with liposarcoma. Recent cytogenetic studies have reaffirmed the separate nature of many of the variants of lipoma. Solitary lipomas commonly have rearrangements of chromosome 12, a finding not encountered in multiple lipomas or in spindle cell/ pleomorphic lipoma. Liposarcoma is the most common adult soft tissue sarcoma. It seldom arises from subcutaneous tissues or from preexisting lipomas, and is seldom found in children. The hallmark of liposarcoma is the immature fat cell or lipoblast. Diagnostic lipoblasts have an eccentric, hyperchromatic nucleus, which is indented or scalloped by the presence of one or more fat vacuoles. It is important that these cells occur in the appropriate histologic background because similar cells can be seen in a variety of nonlipomatous lesions (e.g., silicone reaction). Failure to apply strict criteria in identifying such cells and in noting the milieu in which they occur can lead to overdiagnosis of liposarcoma. Liposarcomas are divided into several subtypes: well differentiated, myxoid, round cell, pleomorphic, and dedifferentiated. Liposarcomas can be conceptualized as occurring in two broad groups, myxoid/round cell liposarcoma and well differentiated/dedifferentiated liposarcoma. Myxoid/round cell liposarcomas occur in middle-aged adults primarily as an extremity lesion. Tumors range from pure myxoid (low grade) to pure round cell (high-grade lesions) with some cases having transitional features. Behavior can be related to the amount of round cell areas. A consistent chromosome abnormality t(12;16) characterizes this spectrum of lesions. Well differentiated/dedifferentiated liposarcomas, in contrast, occur in late adult life as extremity or retroperitoneal lesions. They consist of mature fat interlaced with atypical hyperchromatic cells and rare lipoblasts. These lesions recur commonly, but they do not metastasize. Their behavior is strongly influenced by location, with retroperitoneal lesions having the worse prognosis. As a long-term complication of the disease, these lesions may progress histologically (dedifferentiate), a phenomenon that confers upon them metastatic potential. Dedifferentiation is largely a time-dependent phenomenon that occurs in sites in which there is a high likelihood for clinical persistence of disease (e.g., the retroperitoneum). Dedifferentiated liposarcomas occur in an age group similar to well differentiated liposarcoma, but are found far more commonly in the retroperitoneum. Most occur as de novo lesions, with only a small percentage occurring as a late complication of well differentiated liposarcoma, as described above. They consist of well differentiated areas associated with nonlipogenic sarcoma usually resembling high-grade malignant fibrous histiocytoma or fibrosarcoma. However, the range of histologic features occurring in the dedifferentiated areas is more varied than previously appreciated. Low-grade areas resembling fibromatosis or low-grade fibrosarcoma may be seen as the sole expression of dedifferentiation or may co-exist with high-grade sarcoma. (ABSTRACT TRUNCATED)

Adult↗
PubMed1995

Multifocal congenital hemangiopericytomas associated with Kasabach-Merritt syndrome.

A newborn male with multifocal congenital hemangiopericytomas complicated by Kasabach-Merritt syndrome was treated by excision of a large hemangiopericytoma in the right mandibular area. After excision of this lesion, the associated consumptive coagulopathy abated. Spontaneous regression of other subcutaneous tumours over the thighs and left flank was noted by age 6 months; this illustrates the benign course of most congenital hemangiopericytomas. Surgical excision of congenital hemangiopericytoma is indicated when there is a coexisting consumptive coagulopathy or for the definitive control of large lesions. For smaller lesions and in the absence of Kasabach-Merritt syndrome, the benign nature and predilection for spontaneous regression of congenital hemangiopericytomas render observation as the preferred strategy.

Disseminated Intravascular Coagulation↗
PubMed1995

CD-34 and keratin expression distinguishes solitary fibrous tumor (fibrous mesothelioma) of pleura from desmoplastic mesothelioma.

Solitary fibrous tumors (SFTs) often involve the pleura and also may encompass the peritoneum and nonserosal sites. On occasion SFTs mimics other neoplasms, including desmoplastic mesothelioma. CD-34, initially characterized as a hematopoietic progenitor cell antigen, recently has been identified in a small number of SFTs. Based on this observation, we compared the keratin, vimentin, and CD-34 expression of 19 SFTs and eight desmoplastic mesotheliomas. Fifteen of 19 SFTs (78.9%) expressed CD-34, whereas keratin expression was absent in all SFTs. In contrast, none of the desmoplastic mesotheliomas expressed CD-34 and keratin expression was found in seven of eight (87.5%). Vimentin expression was noted in 18 of 19 SFTs and in seven of eight desmoplastic mesotheliomas. We conclude that CD-34 expression distinguishes SFT from desmoplastic mesothelioma. Additionally, the results of our study support the idea that SFT is not derived from or related to conventional mesothelium.

Antigens, CD↗
PubMed1995

Frozen section consultation. Utilization patterns and knowledge base of surgical faculty at a university hospital.

The authors studied the knowledge base of surgical faculty concerning frozen section consultations at a university hospital to determine whether it had any relationship to the appropriateness of frozen section requests. To accomplish this, the reasons for performing frozen sections during a 3-month period were analyzed, and those request that seemed ambiguous or inappropriate were identified. Simultaneously a 15-item questionnaire was distributed to faculty and housestaff dealing with factual information concerning the technique and limitations of frozen section diagnosis (Questions 1-8), as well as appropriateness of frozen section requests in a number of clinical situations (Questions 9-15). The collective score on items of general information (Questions 1-8) was 69%, whereas scores on Questions 9-15 ranged from 39% on the gynecologic question related to evaluation of a cystic ovarian mass to 81% on the general surgery question regarding evaluation of a soft tissue mass. Of 914 frozen sections, 95% were performed for appropriate reasons, which included evaluation of margins (46%), establishing a primary diagnosis (43%), determining adequacy or viability of tissue (3%), or satisfying immediate patient/family concerns ( < 1%). Five percent of frozen sections were performed for ambiguous or seemingly inappropriate reasons. Because fewer than five faculty members were responsible for the inappropriate frozen section request, the authors did not find that the results of the questionnaire predicted or anticipated situations in which inappropriate requests occurred. Nonetheless, the results of the questionnaire indicate there is important general information concerning frozen sections that is not uniformly shared by surgical faculty, such as the types of tissue that cannot be cut on a cryostat, the reasons for deferred frozen sections, and the situations in which fresh tissue is needed for special studies. The authors suggest the inappropriate frozen section could be diminished by an educational initiative targeted at a relatively small segment of clinical faculty, whereas enhancement of general information regarding frozen section should ideally occur in the broader context of clinical conferences using illustrative case material.

Faculty↗
PubMed1994

Neuroblastoma-like neurilemoma.

We report three cases of neurilemoma occurring in the superficial soft tissue of the palm, posterior neck, and flank that closely resembled neuroblastoma by virtue of a predominance of small, round hyperchromatic schwann cells with scant cytoplasm which, in one case formed perivascular rosettes and, in the others, giant rosettes with central collagen cores. Although the diagnosis of neuroblastic tumor was seriously entertained in all cases, the diagnosis of a schwannoma was substantiated by the finding of focal areas of conventional schwannoma and by the typical immunophenotypic profile. All tumors strongly and diffusely expressed S-100 protein but lacked neurofilament protein, protein gene product (PGP), and synaptophysin. Ultrastructurally the cells contained slender cytoplasmic processes invested with basal lamina, but no dense core granules. All were excised conservatively, and none has recurred during the 2, 12, and 27 month follow-up periods.

Abdominal Neoplasms↗