Ultrastructual morphology of juvenile psammomatoid ossifying fibroma

We investigated the ultrastructural morphology of the hard tissue in a fibro-osseous lesion. Bone samples were obtained from a juvenile psammomatoid ossifying fibroma and were observed under a scanning electron microscope. The lesion had a spongy lamellar structure containing bony tissue. On histological examination, resorbing preexisting lamellar bone associated with a large number of cathepsin K-positive osteoclasts was confirmed. Scanning electron microscopy revealed the bony material to have a cribriform structure and to indicate resorption related to osteoclasts throughout the tumor. These characteristic findings revealed the presence of active bony reconstruction and destruction in this lesion. The spongy calcified structure observed by scanning electron microscopy expressed the characteristic ground glass appearance in computed tomography of this patient. This remarkable activation of osteoclasts may deeply relate to characteristic calcified structure in this lesion. Observation of hard tissue structure under a scanning electron microscope may shed light on the pathology of fibro-osseous lesions in the head and neck.

[Extracranial meningioma: morphological and histogenetical aspects and relations with perineurioma]

The clinicomorphological, immunohistochemical, and ultrastructural characteristics of 11 cases of extracranial meningioma versus 79 soft tissue perineuriomas were studied. There were significant similarities (cell morphology, immunoprofile, ultrastructural features of perineurial differentiation) of both entities. Considering the point of view that arachnoid and perineurial cells are anatomically, embryologically, and functionally related, it is most possible that extracranial meningiomas may be derived from perineurial cells (or their progenitor cell) rather than from displaced arachnoid cells.

Myofibroblastic sarcoma of the nasal cavity and paranasal sinus: a clinicopathologic study of 6 cases and review of the literature

OBJECTIVE

We describe the clinicopathologic features of 6 cases of myofibroblastic sarcoma (MS) occurring in the nasal cavity and paranasal sinus.

STUDY DESIGN

The paraffin-embedded tissues of 6 cases of MS were stained immunohistochemically and examined by electron microscopy.

RESULTS

Clinically, a painless enlarging mass was the most common symptom, followed by the nasal obstruction, epistaxis, copious rhinorrhea, and proptosis. Histologically, the tumors showed a diffusely infiltrative growth pattern and consisted mainly of spindle cells with abundant eosinophilic cytoplasm. The hypocellular myxoid areas and the hypercellular fibrous areas were identified. Immunohistochemically, all 6 tumors were positive for vimentin, alpha-smooth muscle actin, calponin, and fibronectin. Ultrastructural examination in 3 cases showed characteristic features of myofibroblast. Follow-up in 6 patients revealed high local recurrence rate (6 out of 6).

CONCLUSION

Myofibroblastic sarcoma of the nasal cavity and paranasal sinus exhibit diverse histologic appearances and a strong aggressive behavior.

Olfactory neuroepithelioma: an immunohistochemical and ultrastructural study

Three cases of olfactory neuroepithelioma are presented in this report. Histologically, these tumors were composed of small cells with round to oval, relatively hyperchromatic nuclei and scanty cytoplasm. The tumor cells were occasionally observed in tubular formations or rosette-like arrangements. Immunohistochemically, the tumor cells showed a positive reaction for cytokeratin AE1, cytokeratin CAM5.2, Ber-EP4, antisynaptophysin and anti-S100 protein in all cases. In two cases, LH-RH was detected in the tumor cells. Ultrastructurally, the tumor cells had the differentiation features of olfactory epithelium. Olfactory neuroepithelioma is a rare occurrence and it can be very difficult to distinguish olfactory neuroepithelioma from small cell carcinoma, neuroendocrine carcinoma and so-called "olfactory neuroblastoma" on the basis of hematoxylin and eosin stained sections alone. In controversial cases, a diagnosis of olfactory neuroepithelioma must be substantiated by ultrastructural and immunohistochemical findings, particularly regarding the detection of Ber-EP4 and LH-RH immunoreactivity.

Enzootic nasal adenocarcinoma of sheep in Slovenia

SUMMARY Clinicopathological and electron microscopical findings of eight cases of enzootic nasal adenocarcinoma of sheep, diagnosed solely in one big flock in Slovenia between years 2001 and 2003 are described. All affected sheep were female, their mean age was 4.5 +/- 1.5 years and they either belonged to the Istrian pramenka breed (five sheep) or were crossbreeds (three sheep). Tumours that arose from the ethmoid area of the nasal cavity were unilateral in six cases (75%) and bilateral in two cases (25%). All tumours were classified as adenocarcinomas by histopathological examination and they displayed either a combination of tubular and papillary growth or less often solely tubular proliferation. No metastases were detected in regional lymph nodes, brain or other organs. Electron microscopical studies performed on the reprocessed paraffin-embedded tissues revealed the presence of the virus-like particles with an average diameter between 70 and 90 nm.

Epstein-barr virus induced cellular changes in nasal mucosa

A 21-year-old man presented with nasal obstruction of the right nasal fossa of 1 year duration. Nasal endoscopy revealed in the right inferior turbinate head a rounded neoplasm about 1 cm in diameter. Cytologic study of a nasal scraping specimen disclosed numerous clusters containing columnar cells with cytomegaly, prominent multinucleation, markedly sparse shortened cilia; the cytoplasm contained an acidophil area and a small round area that stained poorly; cells with a large intracytoplasmic vacuole that was acidophil and PAS+. Serology tests using the nested polymer chain reaction (PCR) technique on serum, nasal and pharyngeal smears revealed an Epstein-Barr virus (EBV) infection that was confirmed at electron microscopy. The clinical and cytological features resolved 19 months after the initial evaluation.

CONCLUSION

The authors advise carrying out clinical (endoscopy, serology, etc.) evaluation of all endonasal neoplasms and to routinely perform cytological study on nasal scraping specimens. When samples test positive for EBV, nasal and nasopharyngeal endoscopy should be performed regularly to detect possible evidence for nasopharyngeal carcinoma (NPC).

Malignant melanoma with neuroendocrine differentiation: clinical, histological, immunohistochemical and ultrastructural features of three cases

AIM

To document the clinical, histological, immunohistochemical and ultrastructural features of three malignant melanomas showing neuroendocrine differentiation.

METHODS AND RESULTS

Three patients, two with primary cutaneous melanoma and one with nasal mucosal melanoma, subsequently developing or simultaneously presenting with metastatic malignant melanoma, were studied by conventional histological technique, immunohistochemistry of formalin-fixed paraffin-wax embedded tissues, and electron microscopy of epoxy-resin-embedded tumour tissue. Tumours showed either small cell or conventional malignant melanoma cell morphology. One of the three primary melanocytic lesions (the nasal melanoma) exhibited neuroendocrine differentiation immunohistochemically. All three metastatic malignant melanomas showed, in varying combinations, immunohistochemical and ultrastructural evidence for neuroendocrine differentiation: they were positive for the melanocytic markers, S100 protein, HMB-45, Melan-A and tyrosinase, and the neuroendocrine markers chromogranin, synaptophysin and neurofilament protein. Ultrastructural study in two of the metastases revealed neuroendocrine granules but no lattice-bearing melanosomes.

CONCLUSIONS

The cases described are the most comprehensively investigated malignant melanomas showing neuroendocrine differentiation to date, and the first to document neuroendocrine differentiation ultrastructurally in these tumours. Malignant melanoma with neuroendocrine differentiation therefore needs to be recognized among the other, better known variants of malignant melanoma.

Sinonasal acinic cell carcinoma: a clinicopathologic study of four cases

BACKGROUND

Acinic cell carcinoma is a low-grade malignant epithelial salivary gland neoplasm with a predilection for the parotid gland. To date, only 11 cases of sinonasal acinic cell carcinomas have been reported in the English-language literature. We present the clinicopathologic features of four sinonasal acinic cell carcinomas.

METHODS

The demographic data and pathologic material of four patients with sinonasal acinic cell carcinoma identified from the files of the Department of Pathology at The University of Texas M. D. Anderson Cancer Center between 1984 and 2002 were reviewed.

RESULTS

The four patients were two men and two women, with an age range of 42 to 65 years (mean, 54 years). The patients were initially seen with unilateral nasal obstruction. Histologically, all tumors were composed of round to ovoid cells with clear and/or basophilic granular cytoplasm and round, hyperchromatic, small, eccentrically located nuclei. The growth pattern was lobular, solid, and follicular. Histochemically, periodic acid-Schiff diastase-resistant granules were demonstrated in all cases. All patients were treated surgically. In addition, one patient received postoperative radiation. All patients are alive and well, with follow-up from 4 to 17 years.

CONCLUSIONS

Sinonasal acinic cell carcinoma is a distinct low-grade carcinoma that can be distinguished from other neoplasms by light microscopy and histochemical staining methods. Pathologists and surgeons should be aware of the occurrence of this type of salivary gland neoplasm in the sinonasal tract.

In vivo and in vitro effects of macrolide antibiotics on mucus secretion in airway epithelial cells

To examine the in vivo effects of macrolide antibiotics on mucus hypersecretion, we induced hypertrophic and metaplastic changes of goblet cells in rat nasal epithelium by intranasal instillation of ovalbumin (OVA) in OVA-sensitized rats and by intranasal LPS instillation. Oral administration of clarithromycin (CAM) (5-10 mg/kg) significantly inhibited OVA- and LPS-induced mucus production and neutrophil infiltration, whereas josamycin and ampicillin showed no effect. In vitro effects of macrolide antibiotics on airway epithelial cells were examined using NCI-H292 cells and human nasal epithelial cells cultured in air-liquid interface. Mucus secretion was evaluated by ELISA using anti-mucin monoclonal antibodies (anti-MUC5AC and HCS18). CAM and erythromycin significantly inhibited spontaneous and tumor necrosis factor-alpha (20 ng/ml)-induced mucus secretion from NCI-H292 cells at 10-6 to 10-7 M and from human nasal epithelial cells at 10-4 to 10-5 M. MUC5AC messenger RNA expression was also significantly inhibited. These results indicate that the 14-member macrolide antibiotics, CAM and erythromycin, exert direct inhibitory effects on mucus secretion from airway epithelial cells and that they may be useful for the treatment of mucus hypersecretion caused by allergic inflammation and LPS stimulation.

An ultrastructural and immunohistochemical study of olfactory neuroepithelioma with rhabdomyoblasts

A rare case of olfactory neuroepithelioma with rhabdomyoblasts in a 61-year-old man was investigated using electron microscopic and immunohistochemical methods. A large tumor enhanced by gadolinium-diethylenetriamine pentaacetic acid (DTPA) was demonstrated on magnetic resonance imaging (MRI), located within the anterior cranial fossa without bone destruction. The tumor mostly consisted of small cells with scant cytoplasm. Tubular rosettes were often found. Immunoreactivity for cytokeratin and epithelial membrane antigen (EMA) was strongly positive. Most of the tumor cells were shown to be positive for neuron-specific enolase (NSE) and vimentin and weakly positive for synaptophysin and S-100. Rhabdomyoblasts, which showed oval cells with abundant eosinophilic cytoplasm and a nucleus sometimes displaced toward the periphery of the cell body, were frequently intermingled with the tumor cells. The immunoreactivity for myoglobin was frequently positive in these oval cells. The MIB-1 index showed high values, of 20%-40%. About 10% of the tumor cells revealed positivity for p53 protein and vascular endothelial growth factor (VEGF). Ultra-structurally, numerous junctional complexes were observed between cell bodies and processes. The cell processes frequently contained numerous microtubules. There were sometimes numerous filaments with small aggregates of Z-band material and thick filament-ribosomal complexes in the oval cells. They were concluded to be consistent with rhabdomyoblasts on light microscopic and immunohistochemical findings.

Olfactory neuroepithelioma in a dog: an immunohistochemical and electron microscopic study

A case of olfactory neuroepithelioma was investigated electron microscopically and immunohistochemically. The tumor mass was found in the nasal cavities of a 10-year-old female dog, which showed epistaxis, nasal discharge and facial swelling. The tumor tissue consisted of tubular structure of cuboidal to columnar cells and compactly arranged nests of small cells surrounded by a fibrovascular stroma. Mitotic figures were frequently observed. Immunohistochemically, the tumor cells frequently showed positive for neurofilament protein, synaptophysin and/or carnosine in addition to keratin. Ultrastructurally, tight junction was observed between the tumor cells. No dense-cored secretory granules were shown in the tumor cells. These findings indicated that the present tumor had neuronal and epithelial features probably originating from the olfactory epithelium.

Monotypic angiomyolipoma of the nasal cavity: a heretofore undescribed occurrence

A monotypic angiomyolipoma of the nasal cavity in a 34-year-old woman is described. Tumor cells were spindled or epithelioid and contained glycogen and diastase-resistant PAS-positive granules. There were few mitoses, and necrosis was absent, indicating a benign tumor. The stroma was markedly vascular, and a few adipocytes were seen in one area. Cells were positive for melanocyte and muscle markers. Electron microscopy revealed abundant dense granules. Although melanin was absent histochemically, it was present using a chemical assay, and the granules may, therefore, be atypical melanosomes. Fine actin filaments, attachment plaques and lamina were present. Initial assessment of the lesion indicated malignant melanoma, but the immunostaining and histologic features indicated monotypic angiomyolipoma. To the best of our knowledge, this is the first such case in the nasal cavity.

Immunohistochemical and ultrastructural studies of 2,6-dimethylaniline-induced nasal proliferative lesions in a rat two-stage nasal carcinogenesis model initiated with N-bis(2-hydroxypropyl)nitrosamine

Proliferative lesions induced by 2,6-dimethylaniline (DMA) in a two-stage rat nasal carcinogenesis model were immunohistochemically and ultrastructurally investigated. Male F344 rats received diet containing 3,000 ppm DMA for 52 weeks after initiation with a single subcutaneous injection of 2400 mg/kg of N-bis(2-hydroxypropyl)nitrosamine (DHPN). Histopathologically, proliferation of Bowman's glands, glandular hyperplasias, dysplastic foci, adenomas, and carcinomas were observed in treated rats. These nasal lesions mostly arose in the olfactory mucosa of the nasal cavity. Immunohistochemically, they were positive for cytokeratin and/or collagen type IV antibodies. Ultrastructurally, intracytoplasmic dense secretory granules (200-850 nm in diameter), identical to those in normal Bowman's glands, were observed in all the lesions, providing further support from an origin from these glands. Based on their cellular characterization, growth pattern and/or proliferative activity, two morphological continua were evident, one from dysplastic foci to carcinomas and the other from proliferation of Bowman's glands to glandular hyperplasias and adenomas. These results suggest that dysplastic foci arise from Bowman's glands and progress to carcinomas, while proliferation of Bowman's glands result in glandular hyperplasias and adenomas.

Structural and ultrastructural study of the anterior portion of the nasal septum and inferior nasal concha

We used scanning electron microscopy to study and compare the histologic and ultrastructural aspects of the mucosa of the anterior portion of the septum (APS) and the anterior portion of the inferior concha (APINC) in 10 healthy adults and 10 cadavers. We found that (1) in most cases, the types of epithelium were generally the same in both areas--pseudostratified cylindrical ciliated epithelium with goblet cells (respiratory epithelium), stratified cuboidal epithelium, and stratified squamous nonkeratinized epithelium; (2) the APINC had more respiratory epithelium than the APS; (3) the APS had more squamous epithelium than the APINC; (4) the basement membrane of the APINC was thicker than that of the APS; (5) moderate chronic inflammatory infiltrate was more common in the APINC, and mild infiltrate was more common in the APS; and (6) the APINC had more mucous glands and the APS had more serous glands.

True hemangiopericytoma of the nasal cavity

Two cases of nasal tumors with pericytic myoid differentiation are reported. The tumors occurred in a 77-year-old woman and a 60-year-old man as polypoid lesions covered by normal mucosa. Histologically, the tumors were composed of uniform short spindle or stellate cells with indistinct cell borders arranged in narrow and short fascicles. Numerous blood vessels of various sizes were common in both cases. The tumor cells of both cases stained intensely with anti-vimentin and anti-actin antibodies, but not with anti-desmin, CD34, or anti-high-molecular-weight caldesmon antibodies. Ultrastructural examination revealed well-developed actin thin filaments with dense bodies, subplasmalemmal plaques, intercellular junctions, and irregular discontinuous basement membranes. These histopathologic features suggest true pericytic differentiation of the tumors (true hemangiopericytoma), unlike soft tissue-type hemangiopericytoma. Generally, sinonasal hemangiopericytomas are subdivided into soft tissue-type hemangiopericytomas and true hemangiopericytomas identical to the cases presented here. Soft tissue-type hemangiopericytomas are frequently highly aggressive, whereas true hemangiopericytomas show localized benign behavior. Sinonasal true hemangiopericytomas should be strictly differentiated from soft tissue-type hemangiopericytomas.

Comparative ultrastructural study of cytotoxic granules in nasal natural killer cell lymphoma, intestinal T-cell lymphoma, and anaplastic large cell lymphoma

Comparative immunohistochemical and ultrastructural studies were performed on five nasal natural killer (NK) cell lymphoma cases, two intestinal T-cell lymphoma cases, and eight anaplastic large cell lymphoma (ALCL) cases to clarify morphological differences in cytotoxic granules among these cytotoxic lymphomas. Nasal NK-cell lymphomas and intestinal T-cell lymphomas had fine azurophilic granules and displayed dot-like immunostaining of granzyme B- and T-cell intracellular antigen 1 (TIA-1), predominantly in the central area of the cytoplasm. Ultrastructurally, these NK-cell lymphomas and intestinal T-cell lymphomas had two types of cytotoxic granules, type-I granules (dense core granules) and type-II granules (multivesicular bodies), which have been demonstrated in normal large granular lymphocytes in peripheral blood. However, ALCLs did not have azurophilic granules, and only type-II cytotoxic granules were found ultrastructurally, even though they showed similar dot-like immunostained patterns of granzyme B and TIA-1, as seen in NK-cell lymphomas and intestinal T-cell lymphomas. Immunoelectron microscopy revealed that TIA-1 was primarily located at the periphery of the cytoplasmic granules in the NK-cell lymphoma and ALCL cases. These findings suggest that malignant lymphomas with a cytotoxic phenotype can be divided into two types, (azurophilic granule)+, (type-I granule)+, (type-II granule)+ lymphomas and (azurophilic granule)-, (type-I granule)-, (type-II granule)+ lymphomas.

Sequential observation of 2,6-dimethylaniline-induced nasal lesions in a rat two-stage nasal carcinogenesis model after initiation with N-bis(2-hydroxypropyl) nitrosamine

Male F344 rats received diet containing 3,000 ppm 2,6-dimethylaniline (DMA) after initiation with a single subcutaneous injection of 2,400 mg/kg of N-bis(2-hydroxypropyl)nitrosamine (DHPN), and histological and electron microscopic examinations of the nasal cavity were performed at 4, 13, 26 and 52 weeks to examine sequential changes induced by DMA. Severe atrophy of Bowman's glands and epithelial disarrangement were apparent from week 4, followed by dilatation and/or proliferation of Bowman's glands, degeneration of epithelial cells, and proliferation of undifferentiated epithelial cells from week 13. Focal glandular hyperplasias, dysplastic foci, and adenomas were observed from week 26, and carcinomas at 52 week. These nasal lesions were mostly evident in the olfactory mucosa in the nasal cavity, and their severity and/or incidences, other than atrophy of Bowman's glands, increased with the treatment period. Electron microscopically, carcinoma cells demonstrated desmosomes, dense secretory granules identical to those in normal Bowman's glands, a basement membrane, and microvilli. These results suggest that Bowman's glands are the target of DMA, giving rise to nasal carcinomas after DHPN-initiation.

Cytogenetic analysis of a parachordoma

We report the cytogenetic and histopathological findings in a 7-year-old female child with an intranasal tumor that is most consistent with a parachordoma. Karyotypic analysis of the tumor revealed clonal numerical and structural chromosome abnormalities. Seven cells displayed recurrent changes: der(2)t(2;4), del(3q), and the loss of chromosomes 9, 10, 20, and 22. Four cells showed a loss of chromosome 17. To the best of our knowledge, these are the first clonal chromosome abnormalities described in parachordoma.

Olfactory neuroblastoma: a case report

A neuroblastoma arising in the nasal cavity of a 66-year-old male invaded the frontal sinus and extended into the cranial cavity. Light microscopy revealed sheets of small ovoid cells and many small glands bordered by columnar cells which were strongly immunoreactive to epithelial markers. Focal reactivity for synaptophysin and chromogranin was seen within the sheets of small cells. Electron microscopy confirmed the presence of olfactory differentiation.

Olfactory undifferentiated carcinoma with endocranial extension in a Fischer-344 rat

A spontaneous tumor in the nasal cavity, extending through the cribriform plate to the cranial cavity, was detected in a 103-wk-old female Fischer-344/DuCrj rat. The tumor appeared to arise from the olfactory epithelium and was composed of round to polygonal, undifferentiated cells arranged in solid sheet-like and lobular patterns with scant fibrovascular stroma. Ultrastructurally, the tumor cells often formed desmosomes between contiguous cells and had no neurosecretory granules. Immunohistochemically, the tumor cells did not react with any antibodies specific for intermediate filaments, neuronal, muscular, and endothelial elements. Based on these results, the tumor was diagnosed as undifferentiated olfactory epithelial carcinoma.

Solitary fibrous tumor of the nasal cavity and orbit

Solitary fibrous tumors (SFT) are rare spindle cell neoplasms generally associated with the serosal surface, especially the pleura. Two SFT are reported arising in the nasal cavity and orbit, occurring in a 33 year old female and a 21 year old male, respectively. The lesions lacked the characteristic features of other recognized neoplasms that occur in these regions. Immunohistochemically, the tumors cells were diffusely and strongly positive for vimentin and CD34 and some or many tumor cells expressed neuron-specific enolase and Leu-7. Ultrastructurally, the tumor cells showed no distinct features although they were suggested to be primitive mesenchymal or fibroblast-like cells. Both tumors were diploid by flow cytometry. The two patients have had benign clinical courses with limited follow-up. Our findings suggest that SFT is of mesenchymal cell origin and support another location for SFT, indicating additional evidence against mesothelial origin. SFT should be included in the differential diagnosis of spindle cell tumors arising in the nasal cavity and orbit.

Polymorphous low-grade adenocarcinoma arising in the nasal cavities with an associated undifferentiated carcinoma

A case of polymorphous low-grade adenocarcinoma arising in the right nasal cavity of a male patient with previous history of kidney transplantation is reported. The tumor contained extensive areas of undifferentiated carcinoma, probably arising from the low-grade component. This combination of findings has not been previously reported in this variety of salivary gland tumor.

Usefulness of electron microscopy in the diagnosis of "small" round cell tumors of the sinonasal region

The sinonasal region is known to harbor several types of tumors that belong to the general category of "small" round cell tumors and offer considerable diagnostic challenges. This study evaluated 33 cases of such tumors by electron microscopy to characterize their ultrastructural features in conjunction with immunohistochemistry, in an attempt to define diagnostic criteria of various types. Electron microscopy was useful in the proper classification of tumors in 27 cases: esthesioneuroblastoma (EN), 12; undifferentiated carcinoma, 6; melanoma, 3; lymphoma, 3; melanotic neuroectodermal tumor, 1; rhabdomyosarcoma, 1; and pituitary adenoma, 1. In the remaining six cases, the ultrastructural features were those of poorly differentiated carcinomas. They usually exhibited some epithelial characteristics as well as neuroendocrine features by immunohistochemistry and electron microscopy. These tumors could be best described as poorly differentiated neuro-endocrine carcinomas (malignant neuroepitheliomas). The most controversial diagnostic problems existed between the tumors categorized as esthesioneuroblastomas and neuroendocrine (NE) carcinomas. Esthesioneuroblastomas were characterized by uniform round nucleated cells with variable amounts of dendritic processes containing numerous dense core granules ranging from 150 to 350 nm in the perikarya and dendritic processes. Dendritic processes contained longitudinally arranged neural tubules and revealed an occasional synaptic junction. In three of the 12 cases of EN, cells with the appearance of sustentacular cells were recognized by electron microscopy. The NE carcinomas usually consisted of closely packed round cells with scanty cytoplasm that lacked any feature of neuroblastic cells. The tumor cells in this category often were epithelioid in appearance and exhibited a varying degree of cytokeratin positivity. Neuron-specific enolase was also positive in all cases, further suggesting their neuroepithelial nature. The greatest difference between EN and NE carcinomas was the absence of sustentacular cells in NE carcinomas. Immunohistochemical and electron microscopic studies are essential in the differential diagnosis of EN and NE carcinomas, because their microscopic appearance is very similar. The study indicates that EM is useful in the diagnostic categorization of sinonasal tumors of uncertain nature, particularly when it is used in conjunction with immunohistochemistry.

[Olfactory neuroblastoma: a histopathological ultrastructural and immunohistochemical study of 11 cases]

Eleven cases of olfactory neuroblastoma (ONB) were studied histopathologically, ultrastructurally and immunohistochemically. Light microscopical examination showed the tumor cell nests separated by fibrous connective tissue (present in 10/11 ONB), Homer-Wright rosette and/or Flexner rosette (9/11 ONB) and acidophilic fibrillary background (8/11 ONB). Ultrastructurally, there were neurosecretory granules (2/2 ONB) and neurofibrils (1/2 ONB) in cytoplasm of tumor cells. A panel of antibodies were used to characterize the immunohistochemical staining profile of ONB. The following results were obtained for the 11 neoplasms that were immunostained: NSE 11/11 (+), S-100 3/11 (+), Vimentin 4/11 (+), Keratin 1/11 (+) and NF, EMA, CEA, LCA all negative respectively. The significance of the morphological and immunohistochemical features of ONB in diagnosis and differential diagnosis were discussed.

[Ultrastructural characteristics of mast cells and eosinophils in nasal inverted papilloma]

We previously found that an increased number of mast cells and eosinophils accumulated in nasal inverted papilloma and in the nasal mucosa of allergic subjects. Two subtypes of mast cells, i.e., mucosal mast cells and connective tissue mast cells are known to be present in the allergic nasal mucosa. Eosinophils in the allergic nasal mucosa are also heterogeneous. In addition, we demonstrated accumulation of formalin-sensitive mast cells at the tumor site of nasal inverted papilloma. The morphological characteristics and function of mast cells and eosinophils, however, have not yet been identified. The purpose of this study was to determine the ultrastructural characteristics of mast cells and eosinophils in relation to their function in tumor tissue. The results revealed two subtypes of mast cells in nasal inverted papilloma, one distributed mainly in the tumor site, the other mainly in the stromal site. These two subtypes of mast cells had different ultrastructural characteristics. In contrast to stromal mast cells, mast cells in the tumor site were characterized by a smaller cell diameter, fewer specific granules and a higher rate of degranulation. This suggested that they may have played some role in the pathogenesis of the tumor, however, their precise function is still unknown. In comparison with the mast cells in the allergic nasal mucosa, previously reported by Okuda et al, the mast cells in the tumor site were similar to those in the epithelial layer of the allergic nasal mucosa (MMCs), while mast cells in the stromal site resembled those in the lamina propria (CTMCs). There were no marked morphological differences between eosinophils in the tumor site and the stromal site.(ABSTRACT TRUNCATED AT 250 WORDS)

Olfactory neuroblastoma: clinical and pathological aspects

Twenty cases of olfactory neuroblastoma were available for clinical and histopathological evaluation. The usefulness of immunohistochemistry in the diagnosis of this tumour was investigated and was best achieved using a panel of monoclonal and polyclonal antibodies, notably neuron-specific enolase, PGP 9.5, S-100 protein, synaptophysin and chromogranin A. This study confirmed that immunohistochemistry is a useful adjunct in cases where conventional histology is equivocal.

Electron microscopic and immunohistochemical findings in a case of olfactory neuroblastoma

A case of olfactory neuroblastoma is reported. Light microscopic examination showed various arrangements of poorly differentiated tumour cells forming either uniform sheets or convoluted cords of multiple cell layers orientated toward a richly vascular stroma. Electron microscopic examination showed the presence of abundant cytoplasmic filaments and processes, and dense core endocrine vesicles ranging from 100-160 nm in diameter in both the perinuclear region and tumour cell processes. Immunohistochemical staining was positive in most of the tumour cells for neuron specific enolase, and in a few cells for S-100 protein, vimentin, and serotonin, but staining for desmin and keratin produced no reaction.

Cylindrical cell papilloma of the nasal cavity and paranasal sinuses. A histochemical and cytochemical study

A cylindrical cell papilloma occurring in the sino-nasal mucosa of a 61-year-old woman was studied histochemically at both light and electron microscopic levels. The cylindrical cells demonstrated distended intracytoplasmic microcysts with numerous microvillous projections on the apical cell membrane. The retained mucosubstance in the cystic spaces stained intensely with HID-TCH-SP sequence and showed no apparent communication with the extracellular space. These findings indicate that the cylindrical cells may be of mucous-secreting cell derivation, being derived from cells possessing abnormal and/or failed secretory function. The property of sulfated mucin in the 'cylindric' intracytoplasmic cysts is suggested to be the result of endodermal displacement or metaplasia of the Schneiderian epithelium.

Neuroendocrine tumors of the nasal cavity: an ultrastructural and morphometric study of 24 cases

A series of 24 small cell nasal tumors with neuroendocrine differentiation was studied by electron microscopy, and the numbers of secretory granules and cell junctions were assessed. To investigate the relationship between the extent of dendrite formation and the behavior of the tumors, the size of the tumor cells and the area occupied by dendritic processes were determined for each tumor by morphometric analysis performed on low-magnification electron micrographs. A positive correlation was demonstrated between the dendritic area index and the survival of the patients (P = 0.017). Neither the number of secretory granules nor the frequency of cell junctions was prognostically significant.

Detection of human papillomavirus type 6f genome in nasal papillomatosis

Five cases of nasal papillomatosis were studied clinicopathologically and virologically. In a case of recurrent papillomatosis of non-inverted type located on the nasal septum, human papillomavirus (HPV) DNA was detected by dot blot hybridization with an RNA cocktail probe of mucosal HPVs. In Southern blot hybridization, the DNA hybridized with that of HPV types 6 and 11 but not with those of types 16 and 18. Its restriction endonuclease-cleavage patterns corresponded well to those of HPV type 6f. These results suggested that HPV type 6 would also be associated with nasal non-inverted papillomatosis.

Pathology of enzootic intranasal tumor in thirty-eight goats

Intranasal tumors were studied in 38 goats ranging from 7 months to 8 years of age of both Murciana-Granadina and crossed breeds. Tumors were diagnosed in eight herds. Clinically, the affected goats showed a copious seromucous nasal discharge, ocular protrusion, and skull deformations. The tumors originated from the ethmoid region. They involved one or both nasal cavities, although most were bilateral (26/38). The tumors were generally accompanied by inflammatory polyps. The histologic patterns were very similar in all cases, and the tumors were classified as low grade adenocarcinomas of the nasal glands. Histochemical, immunohistochemical, and ultrastructural studies suggested that the serous glands of nasal mucosa were the probable origin of the neoplastic cells. Budding and extracellular retrovirus-like particles were observed ultrastructurally in 6/8 tumors. The similarities between these caprine tumors and nasal tumors in sheep and the etiologic role of the retrovirus are discussed.

Enzootic nasal tumour of goats: demonstration of a type D-related retrovirus in nasal fluids and tumours

Nasal exudate and tumour tissue from goats with enzootic nasal tumours were shown to contain a reverse transcriptase activity associated with a particle of buoyant density typical of retroviruses. The same particle contained a 25,000 Mr protein that cross-reacted with the p27 of Mason-Pfizer monkey virus (MPMV) and with p25 of sheep pulmonary adenomatosis retrovirus. It also contained a low Mr protein related to p10-12 of MPMV.

Fibrous papule of the nose with granular cells: two cases

Two cases of fibrous papule of the nose (FPN) with granular cell features are presented and discussed. Both lesions have classic architectural features of FPN; however, the main stromal cells show large cytoplasmic granules of the type seen in granular cells. We are uncertain of the significance of these findings. Our hypotheses include a perifollicular granular cell reaction and a granular degenerative change of local dermal dendrocytes.

Nasal haemangiopericytoma

Haemangiopericytoma is an uncommon vascular tumour frequently diagnosed with difficulty. The immunohistochemical findings of strong positivity to vimentin together with other diagnostic features (histological and ultrastructural) improves the certainty of its diagnosis. We report a case arising in the nose and outline diagnostic problems especially relating to histopathology.

Spindle cell myoepithelioma of the nasal cavity

Minor salivary gland neoplasms with mesenchymal-like features are uncommon in the sinonasal tract. We herein report a case of spindle cell myoepithelioma of the nasal cavity in a 69-year-old woman who presented with a rapidly expanding tumor accompanied by episodes of epistaxis. Although initially considered as a mesenchymal neoplasm, ultrastructural and immunophenotypical characterization demonstrated its myoepithelial nature. In the sinonasal setting, this unusual neoplasm may be confused with soft tissue tumors showing spindle cell or myxoid features. Staining for cytokeratin is found to be the most useful adjunct to diagnosis.

Leiomyoma of the nasal septum

A case of leiomyoma of the nasal septum is presented together with electron micrographs.

Type C retroviral expression in spontaneous feline olfactory neuroblastomas

Three cases of spontaneous olfactory neuroblastoma (ONB) in domestic cats were morphologically and immunocytochemically characterized. Diagnostic light microscopic features included Flexner and Homer-Wright rosettes, while ultrastructurally the cells had neuritic processes, intracellular intermediate filaments, and intercellular junctions. Immunocytochemically, the tumors stained positively for neuron-specific enolase, cytokeratins, and S-100 protein antigens. In each case, a key finding was the identification of numerous mature type C retroviral particles within the tumors. In one case, budding of viral particles from the plasmalemma of tumor cells suggested the source of mature particles. This cat and one other were tested, and both were serologically positive for feline leukemia virus (FeLV). The virus in the tumors was identified as FeLV by polymerase chain reaction and immunocytochemistry. No other neoplasms were found in any of the cats, nor was there similar evidence of active viral infection in other non-tumor tissues, including the brain. Although the relationship between FeLV infection and ONB is uncertain, our findings indicate that FeLV should be investigated as an etiologic agent of ONB.

Sinonasal hemangiopericytoma. A reassessment with electron microscopy, immunohistochemistry, and long-term follow-up

Sinonasal hemangiopericytomas are rare, occasionally misdiagnosed neoplasms that have often been considered distinct from hemangiopericytomas of other sites. Eleven cases were studied. Nine arose from the nasal cavity and two from the paranasal sinuses. The patients' mean age was 58 years. In nine cases there were no appreciable mitoses; in two, mitoses were frequent. Of 10 cases studied by immunostaining, all were positive for vimentin; two had faint focal staining for actin; one focally expressed S-100 protein; all were negative for cytokeratins, desmin, and Factor VIII-related antigen; and none bound Ulex europaeus agglutinin 1. Five cases were studied by electron microscopy. The most consistent features were basal lamina-like material partly surrounding tumor cells and completely separating them from endothelium, tapered cytoplasmic extensions, and orderly bundles of filaments. Intercellular junctions and pinocytotic vesicles were present in some tumors. Of nine cases with adequate follow-up, tumors recurred in four cases (44%) after a mean of 6.5 years, and none metastasized. A review of the literature showed that high local recurrence rates, late recurrences, and low rates of metastasis were features of tumors in this location. This might be a reflection of early presentation, small tumor bulk, and difficulty of complete resection, rather than evidence for a biologically distinct neoplasm.

Extra-skeletal Ewing's sarcoma of the nasal fossa

Extraskeletal Ewing's sarcoma is rarely found arising in the head and neck region. An unusual case arising in the nasal fossa in a young child is reported and the differential diagnosis, pathology and treatment discussed.

An unusual embryonal tumor of the nasal cavity in a neonate--a nasal blastoma? A clinical, histologic, and ultrastructural study

We report the clinicopathological and ultrastructural features of a primitive embryonal tumor which occurred as a polypoid mass in the nasal cavity of a newborn infant. Its primitive-appearing, glycogen-rich, small round cells exhibited epithelial characteristics histologically, immunohistochemically, and ultrastructurally. The tumor was initially diagnosed as embryonal carcinoma because of evidence for endodermal differentiation and lack of specific features of other types of small round cell tumors of childhood. However, it did not have the characteristic features of endodermal sinus tumor nor the anaplasia of the adult type of embryonal carcinoma. It had some resemblance to embryonic somatic tissues and the blastemal component of some of the primitive tumors of childhood. Because of its unique morphological appearance, which has never been reported, and its relatively indolent behavior after chemotherapy and radiotherapy, we believe that this is a distinctive primitive teratoid tumor which may be classified as nasal blastoma.

"Undifferentiated" neoplasms of the sinonasal region: differential diagnosis based on clinical, light microscopic, immunohistochemical, and ultrastructural features

Sinonasal neoplasms and neoplasm-like proliferations composed of light microscopically poorly differentiated or undifferentiated, small- to medium-sized cells cause considerable diagnostic confusion. Lesions in this category include lymphoepithelioma (undifferentiated carcinoma), olfactory neuroblastoma, small-cell undifferentiated (oat cell) carcinoma, sinonasal undifferentiated carcinoma, malignant melanoma, pituitary adenoma, lymphoid hyperplasia, malignant lymphoma, plasmacytoma, lymphomatoid granulomatosis, rhabdomyosarcoma, mesenchymal chondrosarcoma, small cell osteosarcoma, Ewing's sarcoma, and synovial sarcoma. Many of these lesions can be definitively diagnosed based on light microscopic features alone, but, in some instances, additional techniques such as immunohistochemistry are of value. The authors review the pertinent clinicopathologic features of the above lesions, with emphasis on light microscopic, immunohistochemical, and ultrastructural features of particular utility in differential diagnosis.

[Schwannoma of the nose and paranasal sinuses]

A rare case of a Schwannoma (neurinoma) of the frontal sinus of a 75-year old male patient was examined clinically, histologically, and by electron microscopy. The fine structure of neurinomas occurs in two forms: Type Antoni A is composed of Schwann cells whose nuclei are arranged in palisading rows with greatly attenuated cytoplasmic processes extending from the Schwann cells in parallel alignment; Antoni B is characterized by loosely arranged Schwann cells set in meshwork of macrocysts and reticular fibers. It may be a degenerative form of Antoni A. In the present case Antoni A was the dominating pattern. A prominent basal lamina enveloping Schwann cells, as well as desmosome-like junctions between them, were identified. Furthermore, myelin figures, lysosomal bodies, intranuclear unmyelinated axons and concentric laminated inclusions, and annulate lamellae were found in Schwann cells. Luse bodies appeared in the tumour matrix. It is suggested that annulate lamellae may play a significant role in cell differentiation and tumour growth. No other ultrastructural signs of malignancy were seen.

[Primary amelanotic melanoma of the nasal fossa. Importance of ultrastructural study for diagnosis]

Primitive malignant melanoma of the nasal fossae is rare and amelanotic melanoma of the same site is highly unusual. The present work reports a case where positive diagnosis was only possible by means of ultrastructural study. Giving evidence of the premelanosomes, this technique made it possible to differentiate from other types of cancers (in particular from olfactory neuroblastoma, non differentiated small cell carcinomas and lymphoma). Although in all cases we are dealing with malignancies, the need for a precise histological diagnosis is fundamental to work up an adequate therapeutic protocol. Given the difficulties in getting an electronic microscope in any hospital, the method used in the present case is quite significant since it made precise diagnosis possible even on bioptic fragments fixed in non buffered formalin. Finally some problems regarding diagnosis and treatment linked to diagnosis by means of electronic microscopy are discussed.