Muramidase, alpha-1 antitrypsin, alpha-1 antichymotrypsin, and S-100 protein immunoreactivity in giant cell lesions

Absence of infiltrating peripheral myeloid cells in the brains of mouse models of lysosomal storage disorders

Approximately 70 lysosomal storage diseases are currently known, resulting from mutations in genes encoding lysosomal enzymes and membrane proteins. Defects in lysosomal enzymes that hydrolyze sphingolipids have been relatively well studied. Gaucher disease is caused by the loss of activity of glucocerebrosidase, leading to accumulation of glucosylceramide. Gaucher disease exhibits a number of subtypes, with types 2 and 3 showing significant neuropathology. Sandhoff disease results from the defective activity of β-hexosaminidase, leading to accumulation of ganglioside GM2. Niemann-Pick type C disease is primarily caused by the loss of activity of the lysosomal membrane protein, NPC1, leading to storage of cholesterol and sphingosine. All three disorders display significant neuropathology, accompanied by neuroinflammation. It is commonly assumed that neuroinflammation is the result of infiltration of monocyte-derived macrophages into the brain; for instance, cells resembling lipid-engorged macrophages ('Gaucher cells') have been observed in the brain of Gaucher disease patients. We now review the evidence that inflammatory macrophages are recruited into the brain in these diseases and then go on to provide some experimental data that, at least in the three mouse models tested, monocyte-derived macrophages do not appear to infiltrate the brain. Resident microglia, which are phenotypically distinct from infiltrating macrophages, are the only myeloid population present in significant numbers within the brain parenchyma in these authentic mouse models, even during the late symptomatic stages of disease when there is substantial neuroinflammation. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/. This article is part of the Special Issue "Lysosomal Storage Disorders".

Histopathological, immunohistochemical, and image analytic parameters characterizing the stromal component in primary and recurrent giant cell tumor of bone

Giant cell tumor (GCT) of bone is a benign locally aggressive tumor whose biological behavior is unpredictable. Currently, there are no definitive clinical, histological, biochemical, or immunological parameters that can predict its behavior. This study was undertaken to examine whether delineation of reactive and neoplastic stromal component of GCT can help in this regard. 55 cases of GCT (30 primary, 25 recurrent) were subjected to histopathological grading, immunohistochemistry, and image analysis. Spindling of stroma was more frequent in recurrent GCT with 64% cases having more than 50% spindled stroma (p < 0.001). Number of mitosis/10 HPF and higher grade were more in recurrent GCT. Mean percentage positivity for CD68 (38.36%) and α1-ACT (70.86%) was higher in primary than recurrent GCT. PCNA and MiB-1 labeling indices were higher in recurrent (42.62% and 9.18%, respectively) than in primary group (24.75% and 7.7%, respectively). A single numerical parameter encompassing stromal cell population and its proliferation was derived as ratio of PCNA/CD68 and PCNA/α1-ACT. Both ratios were higher in recurrent (0.81 ± 0.38; 1.58 ± 1.50) than in primary GCT (0.58 ± 0.62; 0.34 ± 0.29) (p = 0.002; 0.01). On image analysis, parameters significantly different between the two groups were nuclear area and nuclear integrated optical density. It was thus concluded that recurrent GCT shows higher grade, increased mitosis, more spindling, fewer reactive components, and higher proliferation than primary GCT. Delineation of reactive component (α1-ACT positive) and proliferating component (PCNA positive cells) using immunohistochemistry with calculation of the PCNA/ACT ratio delivers more information than image analysis.

Expression of CD34 and CD68 in peripheral giant cell granuloma and central giant cell granuloma: An immunohistochemical analysis

Background:

Central and Peripheral giant cell granulomas of jaws are uncommon, benign, reactive disorders that are characterized by the presence of numerous multinucleated giant cells and mononuclear cells within a stroma. The origin of the multinucleated giant cells is controversial; probably originating from fusion of histiocytes, endothelial cells and fibroblasts.

Objective:

To assess the expression of CD34 and CD68 in central and peripheral giant cell granulomas to understand the origin of these multinucleated giant cells.

Materials and Methods:

Twenty cases of Central and Peripheral giant cell granulomas were evaluated immunohistochemically for CD34 and CD68 proteins expression.

Results:

Immunopositivity for CD34 was seen only in cytoplasm of endothelial cells of blood vessels; whereas, consistent cytoplasmic immunopositivity for CD68 was seen in few stromal cells. Statistical significance was seen in mean number of multinucleated giant cells, mean number of nuclei in multinucleated giant cells, CD68 expression and ratio of macrophages to multinucleated giant cells among two lesions.

Conclusion:

Although the central giant cell granulomas share some clinical and histopathological similarities with peripheral giant cell granulomas, differences in mean number of nuclei in multinucleated giant cells and CD68 immunoreactivity may underlie the distinct clinical behavior.

Immunohistochemical comparison of p53, Ki-67, CD68, vimentin, α-smooth muscle actin and alpha-1-antichymotry-psin in oral peripheral and central giant cell granuloma

INTRODUCTION

Giant cell lesions are characterised histologically by multinucleated giant cells in a background of ovoid to spindle-shaped mesenchymal cells. There is a major debate whether these lesions are separate entities or variants of the same disease. Our aim was to study the nature of multinucleated and mononuclear cells from peripheral giant cell granuloma (PGCG), and central giant cell granuloma (CGCG) and giant cell tumor (GCT) of long bones using immunohistochemistry evaluation and to determine whether there is a correlation between recurrence and the markers used.

MATERIALS AND METHODS

Ki-67, p53, Vimentin, smooth muscle specific actin, CD68 and alpha-1-antichymotrypsin were used to study 60 giant cell lesions. These included 26 CGCG, 28 PGCG, and 6 GCT cases using an avidin-biotin-complex immunohistochemistry standard method.

RESULTS

All studied cases showed the same results except the percentage of Ki-67 positive mononuclear cells in PGCG was significantly higher than that of both CGCG and GCT (p<0.05). Interestingly, no statistical correlation between recurrence and the markers used was found.

CONCLUSION

Our results may suggest that these lesions have the same histogenesis. The mononuclear stromal cells, both histiocytic and myofibroblastic, are thought to be responsible for the behavior of these lesions whereas the multinucleated cells are considered as reactive. This might support the argument that PGCG, CGCG and GCT are different variants for the same disease. Further studies using molecular techniques are required to elucidate why some of these lesions behave aggressively than others.

Recurrent case of central giant cell granuloma with multiple soft tissue involvement

Central giant cell granuloma is a fairly common lesion in the jaws aetiology of which is still completely unknown but thought to be of a reactive process to some unknown stimuli. It usually arises either peripherally in periodontal ligament, mucoperiosteum, or centrally in the bone. The histological hallmark for both peripheral and central giant cell granuloma (CGCG) is the presence of distinctive multinucleated giant cells (MGCs) in a prominent fibrous stroma. Central giant cell granuloma is an uncommon benign proliferative lesion that almost exclusively occurs within the jaw. Eventually, it may become aggressive leading to the expansion and perforation of cortex resulting into mobility and displacement of teeth with root resorption. The present case focuses on the dilemma and perplexity in diagnosing aggressive CGCGs, due to its close proximity with respect to pathology, behavior and prognosis from giant cell tumors (GCT). Central giant cell granuloma persuaded extensive destruction to the hard and soft tissues with high rate of recurrence encourage us the need of exploring the possibilities of giant cell tumors having a definitive presence in the jaws.

A case of recurrent multifocal central giant cell granulomas

One case of recurrent multifocal central giant cell granulomas (CGCG) is presented. Initially, the lesions presented concurrently in the maxilla and mandible with subsequent recurrence in the mandible. Now, two recurrences are seen in the maxillary sinus and ethmoid region. The literature regarding multifocal CGCG is reviewed.

Giant cell tumours of the tendon sheath: lack of correlation between nm23-H1 expression and recurrence

Some authors attribute recurrences of giant cell tumours to biological factors which are only expressed in some tumours. Grover et al. (1998) suggested that the risk for recurrence is associated with the down-regulation of the nm23-H1 gene. We reviewed the charts of the 154 patients operated on for giant cell tumours of the tendon sheath and selected a group of patients with recurrence (ten cases) and a group of patients who did not have a recurrence after a minimum follow-up of 3 years (13 cases). Immunohistochemical detection of nm23-H1 was performed blindly of the clinical outcome on the paraffin-embedded specimens of these patients and no correlation was found between nm23-H1 expression and the risk for recurrence.

Esthetic management of peripheral giant cell granuloma

BACKGROUND

Peripheral giant cell granuloma (PGCG) is a relatively rare hyperplastic lesion of the oral cavity. The lesion occurs in females more frequently than males and more often in the mandible than the maxilla. Although the precise etiology of PGCG is unknown, it might represent a local reaction to trauma or irritation.

METHODS

In general, treatment requires a wide excision of the lesion due to its possible recurrence.

RESULTS

This report describes the clinical and histopathological findings of PGCG diagnosed in the maxilla of a young male, as well as the successful treatment of a gingival defect that occurred following excision of the lesion, by placement of a subepithelial connective tissue graft concurrently with the biopsy procedure.

CONCLUSIONS

This report emphasizes the importance of having histopathological data to confirm the clinical diagnosis, and the importance of an adequate excision to prevent recurrence even in less extensive cases.

Peripheral giant cell granuloma associated with dental implants

BACKGROUND

Peripheral giant cell granuloma (PGCG) is a well-circumscribed lesion confined to the alveolar and gingival mucosa. PGCG is considered a reactive lesion caused by local irritation or trauma. The objectives of the present study were to evaluate the incidence of PGCG in peri-implant lesions submitted for histologic examination, to establish its correlation with implant failure, and to discuss its pathogenesis.

METHODS

The study was conducted on 25 periimplant biopsy specimens submitted for histological examination between 1999 and 2001. Sections (5 microm) of paraffin embedded tissues were cut and stained with hematoxylin and eosin.

RESULTS

From the 25 specimens, three (two males and one female, ranging in age from 31 to 69 years) were identified as peripheral giant cell granuloma. The posterior mandible was affected in two cases and the anterior maxilla in one. The clinical appearance was an exophytic mass with a bleeding surface. The time interval between implantation and lesion development was from several months to 6 years. Recurrence following curettage was found in all cases. The implants were stable; however, two were removed either because of bone loss around the implant or because of several recurrences. In all cases healing was uneventful.

CONCLUSIONS

Peripheral giant cell granuloma can develop in association with dental implants. Clinically, the lesions are similar to the classical PGCG. In the present study, the precise incidence could not be concluded because of the small number of selected cases. Due to the aggressive nature of the lesion and the high recurrence rate, implants can fail unless the lesion is detected early and proper surgical removal is performed. Tissue removed from the peri-implant area should always be submitted for histologic examination for accurate diagnosis.

Expression of parathyroid hormone (PTH)-related peptide (PthrP) and PTH/PTHrP receptor in osteoclast-like giant cells

Osteoclast-like giant cells (OCGC), which resemble osteoclasts at both the morphologic and immunohistochemical levels, develop in neoplastic tissue. In bone marrow, parathyroid hormone (PTH)-related peptide (PTHrP) can induce osteoclast differentiation by stimulating osteoclast progenitors through the PTH/PTHrP receptor (PPR). To evaluate the possible involvement of PTHrP in OCGC formation in tumors, we analyzed both PTHrP and PPR expression by immunohistochemistry in giant cell tumor of bone (GCTB) and anaplastic thyroid cancer (ATC) containing OCGC. In all cases of either GCTB (n = 5) or ATC (n = 4), intense stainingfor PTHrP was found in OCGC, but only faintly in mononuclear cells. PPR expression in OCGC was also demonstrated in 3 cases of GCTB and 2 cases of ATC. Double staining for PPR and proliferating cell nuclear antigen (PCNA) revealed that PPR was mainly expressed by PCNA-negative mononuclear cells and OCGC in these tumors. This suggests that OCGC might be derived from non-proliferating mononuclear cells by PTHrP stimulation via PPR. Furthermore, the profiles of PTHrP and PPR expression in OCGC were compared with those in the neoplastic GC found in malignancy (n = 6), osteoclasts in bone with osteoarthritis (n = 5), reactive GC, including Langhans-type and foreign body-type in pulmonary tuberculosis (n = 8), and ruptured epidermal cyst (n = 14) in order to clarify whether their distribution pattern was unique to OCGC. In all cases of malignancy, expression of both PTHrP and PPR was observed ubiquitously in neoplastic GC and mononuclear cells regardless of PCNA immunoreactivity. In contrast, in osteoclasts and reactive GC, PTHrP immunoreactivity was seen in all cases and in 7 of 22 cases, respectively, but no PPR expression was observed in either. In situ hybridization confirmed PTHrP expression at the transcriptional level in OCGC and neoplastic GC, but not in osteoclasts. Thus, although PTHrP expression was commonly observed in various types of multinucleated giant cells, their immunohistochemical profiles for PPR were distinct. We conclude that PPR might play a role during OCGC formation in GCTB and ATC.

Giant cell granuloma of the temporal bone: a case report with immunohistochemical, enzyme histochemical, and in vitro studies

A case of giant cell granuloma (GCG) that occurred in the right temporal bone is reported. The lesion showed histologic features identical to GCG. The multinuclear giant cells (MGCs) in the lesion showed strong reactivity with CD68, but patchy staining for myeloid/histiocyte antigen, alpha-1-antitrypsin, alpha-1-antichymotrypsine, and lysozyme. Activity of tartrate-resistant acid phosphatase was also consistently detected in the MGCs. Some of the mononuclear cells of the lesion exhibited similar immunocytochemical and histochemical reactivity as the MGCs. Ki-67 staining, however, was only detected in the mononuclear cells. The MGCs isolated from the lesion presented characteristic morphology of osteoclasts and possessed the ability to excavate bone in vitro. Thus, the MGCs in GCG appeared to express both macrophage- and osteoclast-associated phenotypes. The mononuclear cells were the major proliferative elements in the lesion and a subpopulation of these cells may represent precursors of the MGCs.

[Clinical and molecular genetic observations on families with cherubism over three generations]

BACKGROUND

Cherubism is a rare fibro-osseous disorder that almost exclusively affects the maxilla and mandible.

CASE REPORT

We report on three affected males in three generations in family A, and ten affected patients in family B. The youngest affected relative in family A also had craniosynostosis. His father and grandfather had cherubism and clubbed fingers.

RESULTS AND DISCUSSION

Cherubism was mapped to region 4p16.3. Because of the associated craniosynostosis, we excluded the FGFR3 gene as a candidate gene for cherubism. The inheritance pattern is autosomal dominant with variable expression. The penetrance is 100% in males and 50-70% in females. We found incomplete penetrance in males, which does not conform with all publications.

Immunohistochemical expression of p53, MDM2, Ki-67 and PCNA in central giant cell granuloma and giant cell tumor

Central giant cell granuloma (CGCG) is a reactive bone lesion that occurs mainly in the jaws. The giant cell tumour (GCT) is a benign locally aggressive neoplasm located near the articular end of tubular bones. Both lesions are characterised histologically by multinucleated giant cells in a background of ovoid to spindle-shaped mesenchymal cells. There is a basic question whether both lesions are separate entities or variants of the same disease. The study of cell cycle-associated proteins may give insights into clarifying such question. The expression of these proteins is also important to determine the cell cycle regulation in both tumours. The purpose of this study was to evaluate the immunohistochemical expression of p53, MDM2, Ki-67 and PCNA in CGCG and GCT. The results demonstrated that, despite the lack of p53 immunoreactivity, all the samples showed wide expression of MDM2. The percentage of Ki-67- and PCNA-positive cells in CGCG was statistically higher than that of GCT Our findings show that CGCG has a higher proliferative activity compared with that of the GCT. Our results also suggest that p53 inactivation by MDM2 expression may be involved in the pathogenesis of giant cell lesions of the jaws and long bones.

Markers for macrophage and osteoclast lineages in giant cell lesions of the oral cavity

PURPOSE

Giant cell lesions of the oral cavity are a well recognized entity. However, the histogenesis of these lesions is still the subject of controversy, with support for both histiocyte/macrophage and osteoclast origins being found in the literature. This study evaluated a set of peripheral giant cell lesions (PGCLs) and central giant cell lesions (CGCLs) for characteristics of both cell types to address this dilemma.

MATERIALS AND METHODS

Detection of histiocyte/macrophage characteristics was accomplished immunohistochemically by evaluating for markers specific for this cell type, namely alpha-1 -antichymotrypsin (1 -ACT) and factor XIIIa antibodies. Detection of osteoclast characteristics made use of the fact that osteoclasts possess a unique enzyme, tartrate-resistant acid phosphatase, which can be appreciated by histochemical procedures.

RESULTS

A large percentage of the multinucleated cells stained with the 1-ACT (38.08% in PGCLs and 15.84% in CGCLs), while only isolated cells stained for factor XIIIa (1.20% PGCLs, 0.99% CGCLs). Isolated stromal cells also were stained. Virtually all multinucleated cells reacted with the tartrate-resistant acid phosphatase stain (99.26% PGCLs, 98.34% CGCLs), as did a number of the mononuclear stromal cells.

CONCLUSIONS

This study supports the contention that GCLs of the oral cavity may arise from precursor cells related to the granulocyte/macrophage line, and may originate from mononuclear cells that express markers for both macrophages and osteoclasts.

Recurrent peripheral giant cell granuloma associated with cervical resorption

A case of recurrent peripheral giant cell granuloma in a 38-year-old man is reported. The lesion was localized on the attached gingiva of the lower left second premolar (tooth #35). The surgical excision of the lesion revealed a superficial resorption of the cervical region of the involved tooth. The resorption was smoothed out, and there was no sign of recurrence or further resorption after 14 months. Root resorption, although extremely rare, may be associated with peripheral giant cell granuloma.

Peripheral giant cell granuloma: a clinical study of 77 cases from 62 patients, and literature review

OBJECTIVES

The aim of this study was to identify the principle clinical features of the peripheral giant cell granuloma (PGCG), and to recognise clinical features of PGCG that are poorly defined.

DESIGN

We reviewed retrospectively 77 cases of PGCG from 62 patients, from our files with respect to incidence, sex, patient age, race, clinical symptoms and signs, radiographic features and recurrence following excision.

RESULTS AND CONCLUSIONS

Our results were largely in agreement with previous reports, although there is wide variation in the results published between series. In addition, some clinical features of PGCG are poorly defined. Little is known about the relative incidences of PGCG and central giant cell granuloma. An association between PGCG and tooth loss may exist, but is poorly defined, and not all PGCG that involve edentulous areas follow recent tooth loss. Information about PGCG recurrence after excision is limited, and does not necessarily follow incomplete excision. Despite the large number of reported cases of PGCG, clarification of some clinical features is required, and may help formulation and interpretation of future laboratory-based research into this poorly understood lesion.

Peripheral giant cell granuloma. An immunohistochemical and ultrastructural study

OBJECTIVE

To study the nature of multinucleated and mononuclear cells from peripheral giant cell granuloma (PGCG).

MATERIALS AND METHODS

Formalin-fixed, paraffin-embedded sections of 40 cases of PGCG were immunohistochemically stained for vimentin, alpha I-antichymotrypsin, CD68, S-100 protein, lysozyme, leucocyte common antigen (LCA), factor VIII-related antigen and muscle cell actin. Six cases of PGCG were also studied by transmission electron microscopy.

RESULTS

Vimentin, alpha I-antichymotrypsin and CD68 were expressed in both the mononuclear and multinucleated giant cells. Dendritic mononuclear cells, positive for S-100 protein, were noted in 67.5% of the lesions, whereas lysozyme and leucocyte common antigen were detected in occasional mononuclear cells. Ultrastructural examination showed mononuclear cells with signs of phagocytosis and sometimes interdigitations with similar cells. Others presented non-specific characteristics and the third type exhibited cytoplasmic processes and occasional Birbeck granules. Some multinucleated giant cells showed oval nuclei, abundant mitochondria and granular endoplasmic reticulum whereas others presented with irregular nuclei and a great number of cytoplasmic vacuoles.

CONCLUSIONS

Immunohistochemical and ultrastructural results suggest that PGCGs of the jaws are composed mainly of cells of the mononuclear phagocyte system and that Langerhans cells are present in two thirds of the lesions.

Estrogen and progesterone receptor status of central giant cell lesions of the jaws

It is well known that the central giant cell lesion (granuloma) of the jaws has a distinct female predilection. In addition, occasional cases of central giant cell lesion have been reported to have undergone marked proliferation in pregnant patients and in those undergoing hormonal therapy. As such, we have evaluated 10 central giant cell lesions for the detection of estrogen and progesterone receptor proteins with the use of immunoperoxidase staining. Surprisingly, however, immunostaining for estrogen receptor protein was essentially negative in all cases examined. Although an occasional mononuclear cell stained weakly positive for estrogen receptor protein, these findings suggest that in most cases, factors other than a direct influence of the ovarian hormones, estrogen and progesterone, are responsible for the development and growth of these lesions.

Immunohistochemical distribution of S-100 alpha-positive cells in bovine mycobacterial and non-mycobacterial granulomas

By means of immunohistochemistry, the distribution of the alpha-subunit (S-100 alpha) and the beta-subunit (S-100 beta) of S-100 protein was studied in bovine granulomas caused by Actinomyces bovis, Actinobacillus lignieresi, Actinomyces (Corynebacterium) pyogenes, Pseudomonas aeruginosa, Staphylococcus aureus, Mycobacterium bovis and Mycobacterium paratuberculosis. S-100 alpha-positive epithelioid cells or dendritic cells were scattered among the predominantly S-100 alpha-negative cells of the mononuclear phagocyte system (MPS). S-100 beta was not found in the MPS cells of granulomas but was observed in the endothelial cells of blood vessels. A positive reaction to S-100 was also seen in normal cells in the lymphoid and mammary tissues. Mycobacterial granulomas contained more S-100 alpha-positive cells than did non-mycobacterial ones.

Immunohistochemical study of bovine lymph nodes with antibodies against S100 protein subunits: comparison between lymph nodes of healthy and Mycobacterium paratuberculosis-infected cattle

Using immunohistochemistry, the differential distribution of the alpha subunit (S100 alpha) and beta subunit (S100 beta) of S100 protein was studied in mesenteric lymph nodes from normal or Mycobacterium paratuberculosis-infected cattle. In epithelioid cell granulomas, S100 alpha-positive epithelioid cells and some giant cells were scattered among S100 alpha-negative cells, which were predominant. The S100 beta-positive and -negative cells contained acid-fast bacilli. The presence of S100 beta-positive cells was not demonstrated in the granulomas. In normal component cells in the lymph nodes, follicular dendritic cells in the germinal centres and endothelium of lymphatic sinus and lymph vessels were positive for S100 alpha. S100 beta was positive only in the endothelial cells of blood vessels. Results shown in the present paper are discussed in light of results obtained in other work on human tissues using the same sources of antibodies.

Peripheral giant cell granuloma: evidence for osteoclastic differentiation

Nine cases of peripheral giant cell granuloma of the oral cavity have been immunohistochemically analyzed to assess the nature of the giant cells. Giant cells were unreactive when tested with antibodies recognizing myelomonocytic and macrophage markers (lysozyme, MAC 387, HAM 56) but showed strong immunoreactivity with MB1, an antibody reactive with osteoclasts. It is concluded that giant cells characterizing giant cell granuloma exhibit a phenotype distinct from other giant cells found in sites of chronic inflammation and may be true osteoclasts.

Touton-like giant cells in periapical granulomas

Two types of multinucleated giant cells were observed in periapical granulomas--the foreign body type and the Touton type. In the Touton type, the nuclei were near the center of the cell, surrounded by foamy cytoplasm. Both types of giant cells reacted positively to lysozyme, alpha 1-antitrypsin and alpha 1-antichymotrypsin, indicating their histiocytic origin.

Features of central giant cell granuloma of the jaws xenografted in nude mice

In order that the growth pattern and histologic and ultrastructural differentiation of the central giant cell granuloma of the jaws be studied, tissue from three lesions was transplanted into nude mice. Xenografts were harvested at 3 weeks, 5 weeks, 8 weeks, and 13 weeks and examined histologically and ultrastructurally. Implants could be identified as firm subcutaneous nodules, but after 3 weeks began regressing. At 13 weeks, almost total regression had occurred. Histologically, grafts were well vascularized and there was no evidence of necrosis. Typical multinucleated giant cells disappeared at an early stage. The ultrastructural features of the grafts showed giant cells lying in close association with uninuclear cells, features suggestive of a fusion process. Many cells containing microfilaments at their periphery were identified in the original lesional tissue as well as in the xenografts. These cells strongly resembled myofibroblasts. Collagen bundles were seen within the cytoplasm of stromal cells. The observations suggest that the multinucleated giant cells represent a stimulus-dependent, differentiated end-stage cell population.

Osteosarcomas and chondrosarcomas of the jaws: immunohistochemical correlations

Clinical, microscopic, and immunohistochemical characteristics of 17 jaw sarcomas are reported. Histologic subtypes included chondroblastic (five), fibroblastic (five), osteoblastic (three), telangiectatic (one), parosteal (two), and chondrosarcoma (one). Reactivity for all antigenic markers in decalcified tissue was judged to be comparable to nondecalcified tissue. All neoplasms were nonreactive for muramidase and leukocyte common antigen. alpha-1 Antichymotrypsin and HLA-DR immunoreactivity was found focally. Positive S-100 staining was found predominantly in chondrocytes. All tumors were positive for vimentin. Cells in focal zones of cartilage were positive for keratin. No distinctive pattern emerged relative to clinical recurrence and histologic subtype or immunotype. Leukocyte common antigen determinations were useful because they distinguished between neoplastic and inflammatory cells. S-100 protein stains helped in the subclassification of chondroblastic osteosarcoma, and vimentin stains confirmed mesenchymal origin. Cross-reactive staining of cartilage with keratin antibodies was regarded as a possible diagnostic pitfall.