Cytopathology in the diagnostic appraisal of uncommon malignant neoplastic lesions

Cytology and fine needle aspiration (FNA) cytology are accepted means of diagnosing and typing of common forms of malignant tumors. However, their usefulness for diagnosing less common neoplasms is not clearly established and this study was designed to examine this. We report four unusual cases of patients with malignant neoplasms in which cytology and fine needle aspiration cytology or aspiration biopsy (FNAC, FNAB) contributed significantly in establishing the diagnosis. These cases facilitate the diagnostic capabilities of cytology over a wide spectrum of neoplasms including rare lymphoproliferative disorders and carcinomas.

[Primary intra-osseous carcinoma]

Primary intra-osseous carcinoma (PIOC) is a rare tumor, defined as squamous cell carcinoma that develops in the jaw bones, having no initial connection to adjacent skin or mucosa. It is locally aggressive, with metastases to regional lymph nodes, (28% of cases) and lung (5% of cases) at the time of diagnosis. Its origin may be di novo or from other odontogenic tumors. The maxillary bones have epithelial tissues; therefore this neoplasm is located exclusively on this site, predominantly in the jaw. PIOC diagnostic criteria are strict and include: squamous cell carcinoma histopathology, lack of commitment and sinus mucosa, ruling out the possibility of metastasis from a distant site with a thorough clinical study and complementary methods. The treatment is, whenever possible, oncologic resection, additional radio and / or chemotherapy. Reconstructive surgery with graft and / or prostheses for aesthetic and functional are also required. We report the case of a 72 years old man who consulted for sore jaw three months after molar extraction. Curettage biopsy was performed and then resected mandible with lymphadenectomy. Histopathological examination showed a poorly differentiated squamous cell carcinoma, infiltrating jawbone with morphological findings linking him to residual odontogenic cyst and metastatic lymph nodes in 15 of 48 isolates. Postoperative radiotherapy was performed, he died at 30 months of diagnosis by progressive deterioration.

Oral leiomyosarcomas: report of two cases with immunohistochemical profile

Leiomyosarcoma of the oral cavity is a very rare tumor associated with aggressive clinical behavior and low survival. In this paper, we report 2 cases of leiomyosarcoma, affecting the gingival mucosa of a 54-year-old female and the maxillary bone of a 63-year-old male. Histologically, the tumors were composed of variably oriented fascicles of spindle-shaped cells with cigar-shaped nuclei and eosinophilic cytoplasm. The lesions were treated by surgical resection. Immunoreactivity to anti-vimentin, anti-smooth muscle actin, anti-desmin, anti-laminin, and anti-muscle-specific actin antibodies were found; conversely, the tumor cells were negative for anti-S100 and AE1/AE3 proteins. This report emphasizes the role of immunohistochemical study for correct diagnosis of leiomyosarcoma.

Spindle basaloid squamous carcinoma of the upper aerodigestive tract: immunohistochemical and clinicopathological study of three cases

We describe the clinicopathological and immunohistochemical features of three spindle (sarcomatoid) basaloid squamous carcinomas in three men aged 73, 69, and 59 years with a history of tobacco and alcohol abuse. Two tumors were located in the hypopharynx and one was located in the nasal cavity. The three tumors have a pedunculated polypoid appearance. Histologically, they were composed of conventional basaloid squamous carcinomas with extensive malignant spindle cell proliferation, comprising more than 50% of the tumor. The sarcomatoid component demonstrated immunoreactivity with one or more epithelial markers. One case in addition expressed CD99 and Bcl-2 and was originally diagnosed as monophasic synovial sarcoma; however, a subsequent biopsy disclosed basaloid squamous cell carcinoma with sarcomatoid stroma. Two patients were treated with surgery and radiation whereas one refused therapy. The patients were alive 14 (case patient 1), 10 (case patient 2), and 8 (case patient 3) months after diagnosis. In the absence of evidence from immunohistochemical or electron microscopy studies, a polypoid malignant spindle cell tumor of a mucosal surface of the upper aerodigestive tract should be considered a sarcomatoid carcinoma until proven otherwise. The type of epithelial component would determine the subtype of sarcomatoid carcinoma.

Nestin expression in odontoblasts and odontogenic ectomesenchymal tissue of odontogenic tumours

BACKGROUND

Nestin, one of the intermediate filaments constituting the cytoskeleton, is a marker of neural stem cells or progenitor cells. Its expression is also related to tooth development and repair of dentine.

AIMS

The aim of this study was to investigate nestin expression in various odontogenic tumours and evaluate its usefulness for histopathological diagnosis.

METHODS

We studied formalin fixed, paraffin embedded specimens from 129 cases of odontogenic tumours and 9 of mandibular intraosseous myxoma. After characterisation of odontogenic ectomesenchymal tissues in these tumours using antibodies to vimentin, desmin, neurofilament, and glial fibrillary acidic protein, we immunohistochemically examined nestin expression.

RESULTS

No differentiation towards muscle and nervous tissues was found in the odontogenic ectomesenchymal tissues. Although almost all the ameloblastomas and malignant ameloblastomas were negative for nestin, odontogenic ectomesenchyme in the odontogenic mixed tumours demonstrated nestin immunolocalisation, particularly in the region adjacent to the odontogenic epithelium. Odontoblasts and their processes, pulp cells near the positive odontoblasts, and flat cells adhering to the dentine showed immunoreaction with nestin in the odontomas and odontoma-like component in the ameloblastic fibro-odontomas. Neoplastic cells in almost half cases of jaw myxoma and one case of odontogenic fibroma expressed nestin.

CONCLUSIONS

The distribution of nestin in the odontogenic mixed tumours suggests that nestin expression in the odontogenic ectomesenchyme is upregulated by stimulation from odontogenic epithelium. In addition, nestin may also be involved in the differentiation from pulp cells to odontoblasts in odontogenic tumours. Therefore, nestin is a useful marker for the odontogenic ectomesenchyme and odontoblasts in odontogenic tumours. Nestin, one of the intermediate filaments constituting the cytoskeleton, is a marker of neural stem cells or progenitor cells. Its expression is also related to tooth development and repair of dentine.

Plasmablastic lymphoma of the oral cavity in an HIV-positive child

A 7-year-old boy with a positive history of vertical HIV transmission presented with a painful swelling over the left upper jaw of 20 days' duration. A provisional diagnosis of non-Hodgkin's lymphoma or embryonal rhabdomyosarcoma was made. Fine-needle aspiration cytology findings were inconclusive, and incisional biopsy tissue on routine stains gave an impression of small round cell tumor with plasmacytoid features. A series of histochemical stains and immunohistochemical studies was carried out to differentiate and characterize this tumor. The salient immunostaining was negativity with all routine small round cell tumor markers and positivity with CD138 and lambda light chain restriction. The heterogeneous presentation of plasmablastic lymphoma as a variant of diffuse large B-cell lymphoma and its histogenesis is documented. Potential pitfalls and differential characterization of AIDS-plasmablastic lymphoma from other closely related tumors are addressed. The importance of excluding other common pediatric small round cell tumors by immunohistochemistry is highlighted. To the best of our knowledge, this is the first report of this entity in a vertically transmitted HIV-positive child.

[Relation between the expression of P-gp and GST-pi in oral and maxillofacial squamous carcinoma and chemoresistance]

OBJECTIVE

To investigating the relation between the expression of P-glycoprotein and Glutathione transferase-pi and the chemoresistance.

METHODS

The expressions of these two proteins in patients with oral and maxillofacial squamous carcinoma and normal oral tissues were detected by immunohistochemistry.

RESULTS

The positive expression rate of P-gp and GST-pi in oral and maxillofacial malignant tumor was 57.1% and 53.6% respectively, and no expression in normal oral tissues; the expression of GST-pi was relevant to the resistance to cisplatin, while the expression of P-gp was relevant to the resistance to chemotherapeutic drug in general.

CONCLUSIONS

The method of immunohistochemistry combining MTT assay in vitro may become an efficient way to predict the sensitivity to chemotherapeutic drug.

Clear cell odontogenic carcinoma

Clear cell tumours, in the head and neck region, are usually derived from salivary or odontogenic tissues, or may be metastatic. A few clear cells may be present in odontogenic cysts, while, odontogenic neoplasms composed predominantly of clear cells are quite rare. They include calcifying epithelial odontogenic tumours (CEOT), ameloblastoma and odontogenic carcinoma. Clear cell odontogenic tumour (CCOT) has been classified in the last WHO classification as a benign tumour, but it is now recognized as a more sinister lesion and current opinion is that CCOT should be designated as a carcinoma. These tumours are characterized by aggressive growth, recurrences, and metastatic disease. A recent review of the literature has yielded 30 cases of tumours with similar characteristics. These tumours have a peak incidence in the 5th-7th decades, with a female predilection. The anterior portions of the jaws, especially the mandible, are most frequently affected. The aggressive potential of these neoplasms is well documented by the extensive invasion of adjacent tissues, multiple recurrences and regional or distant metastases.

Clear cell odontogenic carcinoma: a clinicopathologic and immunocytochemical study of 5 cases

CONTEXT

Odontogenic tumor composed predominantly of clear cells is a rare neoplasm of the jaws that was initially designated as clear cell odontogenic tumor. Subsequent reports in the literature, however, all have indicated that this tumor exhibits an aggressive behavior characterized by infiltrative local growth, recurrence, or metastases.

OBJECTIVE

To ascertain the clinicomorphologic features and biologic behavior of this tumor group, we present 5 additional cases using the term clear cell odontogenic carcinoma.

DESIGN

Histologic and immunohistochemical examinations were performed on clear cell odontogenic carcinomas from 5 patients. Clinical and follow-up data were recorded, and the literature was reviewed.

RESULTS

The patients were 1 man and 4 women with an average age of 42.4 years at diagnosis. Three tumors occurred in the mandible and the other 2 in the maxilla. Four of the 5 cases occurred in the anterior or premolar areas of the jaws, appearing as poorly marginated radiolucencies. All cases consisted of islands and sheets of large clear cells and small basaloid cells with scanty eosinophilic cytoplasm, which were separated by thin, mature, fibrous septae. The tumors were unencapsulated and showed aggressive infiltration of the surrounding muscle and perineural tissues. Most of the clear cells contained cytoplasmic glycogen. Immunocytochemically, the tumor cells were positive for pan-keratin, cytokeratin 19, and epithelial membrane antigen, but were negative for vimentin, S100 protein, desmin, smooth muscle actin, human melanoma antigen (HMB-45), and alpha(1)-antichymotrypsin. Follow-up data showed 4 of 5 patients to have multiple local recurrences, and 1 of these 4 had submandibular lymph node metastasis and a fatal outcome due to uncontrollable tumor growth.

CONCLUSION

These results suggest that odontogenic clear cell neoplasms are at least low-grade malignancies and should be classified as carcinomas.

Myofibrosarcoma of the upper jawbones: a clinicopathologic and ultrastructural study of two cases

Two problematic spindle cell sarcomas involving upper jawbones in two adult male patients have been studied by histology, immunohistochemistry, and transmission electron microscopy, and respectively graded as low-grade malignancy and high-grade malignancy. While any single methodological study did not allow confident classification of them into one or other of the classical categories of spindle cell sarcomas (fibrosarcoma versus leiomyosarcoma), the overall contribution from all three methodologies ultimately allowed them to be categorized as sarcomas with myofibroblastic differentiation. Histologically, both tumors had morphological features of an amalgama between neoplastic fibroblasts and smooth muscle cells. Immunohistochemically, both tumors expressed reactivity only for muscle specific actin and alpha smooth muscle actin, in addition to vimentin. Ultrastructurally, both tumors, while showing fibroblast-like cytoplasmic features, had a spurious and imperfectly organized cell surface defying convincing classification into any of specific categories (i.e., both appeared in terms of ultrastructure as poorly differentiated sarcoma, the former with low level of smooth muscle differentiation and possibly the presence of some fibronexus component, the latter with no smooth muscle differentiation but with possible evidence of very rare fibronectin fibril). Therefore, on balance, the most tenable diagnosis seemed to us that of a myofibrosarcoma in both cases. This work is presented considering the fact that myofibrosarcoma currently represents a topical theme of debate, and that this is the first report in medical literature concerning with myofibrosarcomas of the head and neck area in adults.

Pigmented intraosseous odontogenic carcinoma of the maxilla: a pediatric case report and differential diagnosis

We report a pigmented intraosseous odontogenic carcinoma of the maxilla occurring in a 6-year-old Japanese boy. Grossly, the tumor showed solid, gray-yellow, and markedly pigmented appearance. Histology showed neoplastic growths of atypical epithelial cells that occasionally contained melanin pigments. Melanocytes with dendritic processes were often found in the tumor cell clusters, and solitary or aggregated melanophages were scattered within the dense fibrovascular stroma. The tumor cells were diffusely positive for cytokeratins and epithelial membrane antigen, and focally positive for vimentin, neuron specific enolase, neurofilament protein, carcinoembryonic antigen, and amelogenin. Ultrastructural studies showed well-developed intercellular junctions, mainly desmosomes, and glycogen particles. In addition, some tumor cells contained melanosomes and/or a few neurosecretory granules. We consider that the present tumor suggests a close association of ectoderm, mesenchyma, and neuroectoderm in embryogenesis of the tooth, and can raise a diagnostic confusion with melanotic neuroectodermal tumor.

Immunohistochemical evaluation of PCNA and Ki-67 in ameloblastoma

Thirty-two ameloblastoma tissues were immunohistochemically studied using monoclonal anti-proliferating cell nuclear antigen (PCNA) and anti-Ki-67 antibodies. Positive cells were evaluated and analyzed in relation to the WHO classification, cytological pattern of the outer layer cell, clinical appearance, tumor location, radiographic appearance and patient's age. In regard to the cytological pattern of the outer layer cells, the basal cell type had significantly higher PCNA and Ki-67 (P<0.05) labeling indices than the cuboidal cell type. The solid type had significantly higher PCNA and Ki-67 (P<0.05) labeling indices than the cystic and the mixed type. The labeling index of the younger patient was found to be the lowest, the middle age was in the middle and the older patient was the highest. These results indicated that the proliferating activities of ameloblastomas are quite variable, and the evaluations of Ki-67 and PCNA seem to be good indicators to assess the proliferating activity of each type of ameloblastomas.

[Metastasis of pleural malignant mesothelioma to the brain and upper maxilla: description of 2 cases]

Two cases of malignant mesothelioma metastatic to the brain and maxillary bone respectively are reported. This latter localization has never been described in literature. The diagnosis resided primarily on immunohistochemistry.

A novel cell line that retains the morphological characteristics of the cells and matrix of odontogenic myxoma

Little is known about the histogenesis of the human odontogenic myxoma or the relation between tumour cells and the matrix. In order to attempt to remedy this situation, we established and investigated a cell line derived from a human odontogenic myxoma. To our knowledge this is the first cell line derived from this tumour. The cell line, named Mix 1, preserved features of the tumour cells. Mix 1 cells expressed vimentin, type I collagen, fibronectin, tenascin and hyaluronic acid. Ultrastructural analysis of cells of the tumour and cell line demonstrated similarities, both containing Golgi apparatus, rough endoplasmic reticulum and mitochondria indicative of secretory cells. Ultrastructural analysis showed the matrix to be represented by bundles of collagen fibrils in the tumour, and by irregular filaments in cultures more than 60 days old. The Mix 1 cell line promises to be an excellent model for investigating the biology of the odontogenic myxoma.

Clear cell variant of calcifying epithelial odontogenic tumor (CEOT) in the maxilla: report of a case with immunohistochemical and ultrastructural investigations

A rare case of clear cell variant of calcifying epithelial odontogenic tumor is presented with immunohistochemical and ultrastructural investigations. A 14-year-old Japanese girl was admitted with a complaint of swelling in the right posterior maxilla. Radiological examination showed a well-circumscribed radiolucent lesion located close to the impacted third molar. After only a partial tumor excision, the tumor recurred 13 years later. It appeared radiologically as an irregular radiodensity, and a subtotal maxillectomy was performed. Histological examination showed sheets and/or strands composed almost entirely of clear vacuolated epithelial cells in a stroma containing intercellular amyloid-like material and calcification. Histochemical and ultrastructural analysis detected cytoplasmic glycogen granules in the clear cells, and positive immunoreactivities for cytokeratins 8, 13 and 19; filaggrin and anti-ameloblastoma antibodies suggested an odontogenic epithelial origin.

Immunohistochemical study on histogenesis of congenital epulis and review of the literature

Congenital epulis is a very rare lesion found only in newborn infants. This tumor is multiple in about 10% of reported cases, rarely with the simultaneous involvement of the maxilla and mandibula, as in this article. In the presented case, light microscopy demonstrated large eosinophilic granular cells arranged in solid nests that are separated by thin fibrovascular areas. The tumors in the maxilla and mandibula were investigated with a panel of polyclonal and monoclonal antibodies, and using immunoperoxidase methods on formalin-fixed, paraffin-embedded sections. Immunohistochemical studies revealed strong and diffuse cytoplasmic staining for neuron specific enolase and vimentin. However, all other reactions were negative. These results suggest that the congenital epulis may be derived from uncommitted nerve-related mesenchymal cells.

Odontogenic myxofibroma arising from the periodontal ligament in the maxillary molar region

A rare case of odontogenic myxofibroma, which arose from the periodontal ligament and expanded into the oral cavity resulting in an epulis-like lesion in a 52-year-old man, is reported including details of studies using lectin histochemistry, transmission electron microscopy (TEM), and immunohistochemistry. Most of the tumor cells, which appeared spindle-like with abundant rough endoplasmic reticulum and some microfilaments by TEM, showed immunoreactivity for mesenchymal markers. Some tumor cells, which were polygonal and contained many microfilaments and some filament bundles, were immunoreactive for muscle markers. The present case was considered to consist of many fibroblasts and some myofibroblasts.

A clinicopathological and immunohistochemical study of the calcifying epithelial odontogenic tumour (Pindborg tumour) in Malaysians

We reviewed the clinicopathological characteristics of 13 cases of calcifying epithelial odontogenic tumour (CEOT) (Pindborg tumour) diagnosed in the Division on Stomatology, Institute for Medical Research, Kuala Lumpur, over a 29-year period. There were eight female and five male patients. These consisted of eight (61.5 per cent) Malays, three (23.1 per cent) Chinese, one (7.7 per cent) Indian and one (7.7 per cent) Melanau. Their ages at presentation ranged from 19-61 years (mean age, 31.8 years). There were 12 central and one peripheral CEOT. Of these, 76.9 per cent of cases were located in the maxilla, the remaining in the mandible. The commonest clinical diagnosis was a dentigerous cyst (66.7 per cent). Enucleation was the main mode of treatment. Histologically, sheets and strands of polyhedral epithelial cells containing eosinophilic, homogeneous globules with Liesegang rings were observed. One case also showed extensive calcification and clear cell differentiation. Immunohistochemistry revealed a variable keratin staining of the CEOT epithelium, confirming its heterogeneity.

Myoepithelial tumors of salivary glands: a clinicopathologic, immunohistochemical, ultrastructural, and flow-cytometric study

Myoepitheliomas of the salivary glands remain a controversial entity. To contribute to the knowledge of this entity, 16 myoepithelial tumors of the salivary glands were studied: 12 benign myoepitheliomas (BME) and 4 malignant myoepitheliomas (MME). The clinical and the histologic findings of each case were studied Immunohistochemistry and flow-cytometry analysis were performed from the paraffin-embedded material in 15 cases. An electron-microscopy study was performed in 8 cases. The myoepithelial tumors affected patients of both sexes equally. The mean age of the patients with BME was 54 years, and the mean age of patients with MME was 62 years. Eight cases of BME originated in the parotid gland and 4 cases originated in the minor salivary glands. All the MME developed from a benign preexistent tumor: two developed from a pleomorphic adenoma in the parotid gland, and the other two MME developed in the minor salivary gland from a BME. The myoepithelial tumors were composed of epithelioid, plasmacytoid, spindle, or clear cell types, and they showed a solid or a myxoid pattern of growth. Immunohistochemical studies revealed marked and diffuse positivity to cytokeratins, vimentin, and S-100 protein in all cases. Glial fibrillary acidic protein was positive in 8 cases (53%), and muscle-specific actin and smooth-muscle actin were positive in only 3 cases (20%); they were all cases of BME. Desmin was negative in all tumors. Ultrastructural studies showed the presence of basal membrane, tight junctions, intermediate filaments, and microvilli as well as actin-like filaments lacking focal densities in all cases. But actin-like filaments with focal densities were not identified. Flow cytometry determined that all BME were diploid with a mean proliferative index of 7.73%. Two of the MME were diploid and the other two MME were aneuploid. The mean proliferative index of MME was 11.93%. In conclusion, BME and MME originated in major and minor salivary glands can display different histologic patterns and cellular features. Some immunohistochemical and ultrastructural characteristics have been found in all these neoplasms, which supports the idea that myoepitheliomas are composed by neoplastic modified myoepithelial cells, not fully differentiated. These techniques can be useful for the diagnosis of these tumors.

Calcifying epithelial odontogenic tumours in small domesticated carnivores: histological, immunohistochemical and electron microscopical studies

Histological, immunohistochemical and electron microscopical studies revealed one feline and four canine calcifying epithelial odontogenic tumours in 115 oral tumours over a 10-year period. The tumours consisted of islands and sheets of odontogenic epithelium of varying size within a stroma of fibrous connective tissues. The tumour cells were pleomorphic with variable amounts of eosinophilic cytoplasm and large hyperchromatic, polymorphic nuclei with prominent nucleoli. Clusters of keratinized tumour cells ("shadow cells") were frequently seen within the islands and sheets. The multiple spherules of homogeneous eosinophilic material stained positively with Congo red and Dylon stains and produced an apple green birefringence under polarization microscopy, indicative of amyloid. Mineralized foci were scattered throughout the tumour masses and in the homogeneous spherules. Immunohistochemically, the tumour cells reacted with anti-human keratin antibody, but not with anti-human vimentin or anti-chicken desmin antibodies. The homogeneous spherules did not react with anti-human keratin, anti-human vimentin, anti-chicken desmin, anti-amyloid A, anti-laminin or anti-human collagen (type I, III, IV) antibodies. Ultrastructurally, the cytoplasm of tumour cells was abundant and contained a large number of electron-dense bundles of tonofilaments. The homogeneous spherules consisted of fine filaments measuring about 10-12 nm in diameter.

Abnormalities and the implication of retinoblastoma locus and its protein product in head and neck cancers

Abnormalities in the Retinoblastoma tumor suppressor gene (Rb) have been observed in a large number of human cancers. Loss of heterozygosity (LOH) is a common mode of allelic inactivation of Rb and other tumor suppressor genes. We investigated DNA from 45 primary human head and neck cancers to determine LOH at the Rb locus using a polymerase chain reaction-based restriction fragment length polymorphism assay. Of informative cases, we found LOH in 4 of 28 (14%) head and neck cancers. Of immunohistochemical staining of Rb protein, we found that in one of ten LOH negative cases the nuclei of fibroblasts were stained with anti-Rb antibody but there was no nuclear staining tumor cells. These results suggest that inactivation of Rb protein is involved in the carcinogenesis of head and neck cancer at all levels of the process of protein expression: DNA, mRNA and protein.

Amelanotic melanoma of the oral cavity

A case of amelanotic melanoma arising in the upper molar region, which was difficult to diagnose histologically, is reported. The patient was a 79-year-old woman, who complained of a painful swelling in the gingiva of the left upper molar region. Routine histological examination showed that the lesion was composed of diffusely scattered atypical cells with round, spindle-shaped and irregular nuclei and scanty fibrous connective tissue. A fascicular arrangement was often found in the lesion, and no cancer nests were observed. Immunohistochemical study demonstrated positive staining for S-100 protein in both the nuclei and cytoplasm of the tumor cells. Electron microscopic examination revealed that cell organelles were abundant, and an interrupted basal lamina was often found along the cell membrane. The preliminary diagnosis was a non-epithelial malignant tumor. After surgery, histological examination of metastases in lymph nodes from the submandibular region revealed that the tumor cells contained melanin pigment in the cytoplasm, as confirmed by Masson's melanin stain. The final pathological diagnosis was therefore amelanotic melanoma. Immunohistochemical staining for S-100 protein may be useful for differential diagnosis of amelanotic melanoma in conjunction with electron microscopic examination.

Odontogenic myxoma: histochemical and ultrastructural study

Three cases of odontogenic myxoma are presented, two of which were located in the mandible and one in the maxilla. All cases demonstrated similar morphology by light microscopy. Immunohistochemical studies demonstrated positive reaction with antibodies to vimentin and actin, and negative reaction to antibody to S-100 protein. A 127-day-old human tooth bud was used as a control. The ultrastructural features performed on Case 3, when combined with the immunohistochemical findings suggest that the cells comprising odontogenic myxoma are of myofibroblastic origin.

Heterologous tissue elements in melanotic neuroectodermal tumor of infancy

Two cases of melanotic neuroectodermal tumor of infancy (MNTI) contained highly cellular stromal areas consisting of spindle cells exhibiting mitotic activity. In one case, single spindle cells exhibited the same immunohistochemical profile as tumor cells forming part of the epithelial component. In the other case woven bone was formed in a dense fibroblastic stroma. These tumor parts were judged to be heterologous tissue elements that also may be observed in other kinds of neuroectodermal tumors and that reflect the potential of the neural crest to differentiate into various mesenchymal tissue types.

The nature of the eosinophilic and laminated masses in the adenomatoid odontogenic tumor: a histochemical and ultrastructural study

The eosinophilic and laminated masses in AOT were investigated with the light and electron microscope in two cases. The results showed that the eosinophilic amorphous masses were heterogenous and consisted mainly of three types of fibrils. These were: thin collagen, electron dense fibrils probably resulting from degradation of collagen and masses of amyloid filaments with or without collagen fibers in normal and degraded forms. In addition some of the eosinophilic deposits resulted from changes surrounding blood vessels which led to deposition of either collagen or fine filaments arranged into layers around these vessels. In all these areas there was a peripheral layer of fine filaments perpendicular to the epithelial basal lamina, similar to that found in early dentin formation. This layer may be responsible for the reticulin staining found in this tumor. On the other hand the great majority of the laminated masses represented calcified amyloid with or without areas of calcified degraded collagen which were indistinguishable from amyloid. The results suggest that the various fibrils forming the eosinophilic masses in AOT are probably related and may be the result of changes in blood vessels. They also revealed that calcification involves mainly amyloid.

[A quantitative immunohistochemical analysis of bone morphogenetic protein (BMP) in osteosarcoma of jaw]

The monoclonal antibody against bone morphogenetic protein (BMP-McAb) was first used for demonstration of bone morphogenetic protein (BMP) in 13 patients with osteosarcoma. Using avidin-biotin complex method (ABC), we demonstrated that BMP mainly existed in the tumor cell cytoplasm and tumorous osteoblast with positive staining in 10 out of 13 osteosarcoma patients. Using this staining method, we can not only differentiate osteosarcoma from fibrosarcoma (all are negative) and other non-osteogenic tumors, but also further classify osteosarcoma according to the BMP content and distribution by means of quantitative histological analysis. The BMP quantity of osteosarcoma with the patients' clinical situation will be useful in clinical diagnosis, treatment and prognosis. The relationship between BMP and the formation of the tumorous bone, and the relation between BMP and the process of osteosarcoma are discussed.

A variant of calcifying epithelial odontogenic tumor with Langerhans cells

A variant of calcifying epithelial odontogenic tumor (CEOT) with Langerhans cells is reported. Compared to a typical CEOT, the tumor islands of this case were thin and composed of a small number of polyhedral epithelial cells. Almost no calcification of homogeneous eosinophilic materials was observed. In addition, clear cells which structurally corresponded to Langerhans cell were intermingled in the epithelial islands. These cells stain positively for S-100 protein, lysozome, MT 1, LN-3 and OKT 6 antibodies, but not for keratin antibody. Electronmicroscopic examination revealed the rod-shaped and racket-shaped structures called Birbeck's granules in the cytoplasm of these clear cells. Our observations indicate a variant case of CEOT with Langerhans cells in tumor nests.