Chrysotile fibers in tissue adjacent to laryngeal squamous cell carcinoma in cases with a history of occupational asbestos exposure.

Asbestos describes a group of naturally occurring fibrous silicate mineral compounds that have been associated with a number of respiratory maladies, including mesothelioma and lung cancer. In addition, based primarily on epidemiologic studies, asbestos has been implicated as a risk factor for laryngeal and pharyngeal squamous cell carcinoma (SCC). The main objective of this work was to strengthen existing evidence via empirical demonstration of persistent asbestos fibers embedded in the tissue surrounding laryngeal and pharyngeal SCC, thus providing a more definitive biological link between exposure and disease. Six human papillomavirus (HPV)-negative laryngeal (n = 4) and pharyngeal (n = 2) SCC cases with a history working in an asbestos-exposed occupation were selected from a large population-based case-control study of head and neck cancer. A laryngeal SCC case with no history of occupational asbestos exposure was included as a control. Tissue cores were obtained from adjacent nonneoplastic tissue in tumor blocks from the initial primary tumor resection, and mineral fiber analysis was performed using a scanning electron microscope equipped with an energy dispersive X-ray analyzer (EDXA). Chrysotile asbestos fiber bundles were identified in 3/6 of evaluated cases with a history of occupational asbestos exposure. All three cases had tumors originating in the larynx. In addition, a wollastonite fiber of unclear significance was identified one of the HPV-negative pharyngeal SCC cases. No mineral fibers were identified in adjacent tissue of the case without occupational exposure. The presence of asbestos fibers in the epithelial tissue surrounding laryngeal SCC in cases with a history of occupational asbestos exposure adds a key line of physical evidence implicating asbestos as an etiologic factor.

[Laryngeal paraganglioma]. / Paraganglioma gortani.

The paper describes a clinical case of laryngeal paraganglioma, a rare tumor. It provides the detailed characteristics of current diagnostic techniques.

[The electron microscopic study of tumour-like structures on the vocal cords].

We have undertaken the electron microscopic investigation into peculiarities of six tumour-like structures on the vocal cords. The study has demonstrated changes in the number and distribution patterns of intercellular junctions, keratin and tonofilament contents in epithelial cells, basal membrane structure, and composition of the basic substance in lamina propria. All the examined tumour-like structures contained bacteria an two of them had viral particles in vacuoles of fibroblasts. Moreover, the bacteria were found on the surface of epithelium, between epithelial cells and in the basic substance in lamina propria. Cytoplasm of epithelial cells and fibroblasts not infrequently contained bacteria in the phase of division.

Comparative ultrastructure analysis of radiation-induced radioresistant laryngeal cancer hep-2 cell line.

Radioresistance is one of the main reasons for the failure of radiotherapy in laryngeal cancer. However, the mechanisms of radioresistance of tumor cells have remained elusive. This study was conducted to identify the ultrastructural changes of radiation-induced radioresistant laryngeal cancer hep-2 cell line. First, a radioresistant hep-2R cell line was generated after prolonged exposure to γ-rays for 60 Gy (6 Gy/day, 2 days/week) and was confirmed by clonogenic assay. Next, the ultrastructural differences between hep-2R cells and hep-2 cells were compared by transmission electron microscopy. Finally, the results showed that hep-2R cells showed significant resistance to radiation compared with parental hep-2 cells. Increased cell nucleus atypia, more rough endoplasmic reticulum and less mitochondria were observed in hep-2R cells. The amount of microvilli of hep-2R was similar to hep-2 cell. In summary, these ultrastructural differences revealed the morphological mechanism that hep-2R cells had stronger radioresistance than hep-2 cells.

[Effects of protein kinase CK2α on apoptosis and ultrastructure of laryngeal carcinoma cells].

OBJECTIVE: To investigate the effect of protein kinase CK2α on apoptosis and ultrastructure of human laryngeal carcinoma cells and its possible mechanism. METHODS: The siRNA expression plasmid psiRNA-hH1neo-CK2α specific to protein kinase CK2α and non-specific siRNA expression plasmid psiRNA-hH1neo-cont were transfected into Hep-2 cells respectively by lipofectamine method. Western blot was used to detect the expression of kinase CK2α protein. The apoptotic rate was measured by Annexin V-FITC/PI double-staining. The morphological changes of Hep-2 cells were observed under transmission electron microscope (TEM). The expressions of bcl-2 and Bax protein were measured by Western blot. RESULTS: The expression of protein kinase CK2α protein significantly decreased in the Hep-2 cells transfected with psiRNA-hH1neo-CK2α (P < 0.01). Compared with the untransfected cells and siRNA-hH1neo-cont transfected group, psiRNA-hH1neo-CK2α transfected group presented with classical ultrastructural features of apoptosis, such as karyopyknosis, chromatic agglutination adjacent to nuclear membrane and apoptotic body. The apoptotic rate of psiRNA-hH1neo-CK2α transfected group was obviously higher than that in untransfected cells and siRNA-hH1neo-cont transfected group (25.66% ± 0.83% vs 3.66% ± 0.43%, 5.18% ± 0.22%, both P < 0.05). Compared with two other groups, the bcl-2 protein expression of psiRNA-hH1neo-CK2α transfected group decreased (0.20 ± 0.09 vs 0.72 ± 0.16, 0.56 ± 0.11, both P < 0.01), the Bax protein expression increased (0.81 ± 0.17 vs 0.26 ± 0.12, 0.33 ± 0.17, both P < 0.01) while the ratio of bcl-2 to Bax decreased (0.25 ± 0.05 vs 2.76 ± 0.21, 1.70 ± 0.22, both P < 0.01). CONCLUSION: Protein kinase CK2a plays an important role in the apoptosis of human laryngeal carcinoma cells possibly by decreasing bcl-2/Bax. Protein kinase CK2a may provide a potential therapeutic target against human laryngeal carcinoma.

[The cytoskeleton and immigration of laryngeal squamous carcinoma cell affected by Fascin-1 expression].

This study sought to detect the effect of Fascin-1 expression on the cytoskeleton and immigration of laryngeal squamous carcinoma cell. In the experiment, Fascin-1 expression in Hep-2 cells was inhibited by small interfering RNA. The cytoskeleton of Hep-2 cells was observed with the use of laser scanning confocal fluorescence microscope. Millicell insert was applied to detect the immigration of Hep-2 cells in vitro. The results showed that the integrity of cytoskeleton in Hep-2 cells was broken with the down-regulation of Fascin-1 expression and the immigration ability was decreased significantly (P < 0.05). The inhibiting ratio of cell immigration was 44.6 +/- 6.3%. In conclusion, inhibition of Fascin-1 expression in Hep-2 cells could break the integrity of cytoskeleton and decrease the ability of cellular immigration.

Laryngeal papillomatosis: morphological study by light and electron microscopy of the HPV-6.

UNLABELLED: Laryngeal papillomatosis is the most frequent benign neoplasia in children. It is caused by HPV 6 and 11. The lesions are exophytic and highly recurrent, compromising the airway mucosa, mainly the larynx. Study design--clinical prospective. AIMS: To show morphologic alterations of the epithelium (light and electron microscopy) in the HPV-6 lesions. METHODS: Specimens of laryngeal lesions obtained during surgery of four children (1 male, 3 female) were submitted to HPV typing (PCR), light microscopy and electron microscopy. RESULTS: In all specimens, HPV type 6 was found. Epithelial projections were found by electron microscopy with superficial cells in desquamation. Light microscopy showed exophytic projections of the keratinized stratified squamous epithelium overlying a fibrovascular core. Koilocytes (vacuolated cells), suggesting the viral infection by HPV, were identified. No alterations were seen in the basement membrane and corion. Ultraestrutural analysis showed vacuolated cells with clear cytoplasmic inclusions, intercellular injuries and widening intercellular spaces. CONCLUSIONS: morphologic alterations of the epithelium in the HPV-6 lesions are superficial, and additional studies including the others HPV types are needed to show the more aggressive and extensive aspect of the disease.

Ultrastructural evaluation of 585-nm pulsed-dye laser-treated glottal dysplasia.

OBJECTIVE/HYPOTHESIS: To describe the ultrastructural changes occurring within pulsed-dye laser (PDL)-treated glottal tissues. STUDY DESIGN: Prospective. METHODS: Nine patients presenting with glottal dysplasia requiring biopsy to rule out microinvasive carcinoma were enrolled in this prospective study. At least two samples were obtained in each case: one from a PDL-treated area and another from a non-PDL-treated area (obtained from a nonphonatory region as an internal control). In some cases, a third sample was obtained from the junction between PDL- and non-PDL-treated areas. All samples were examined with light microscopy (H and E stain) and transmission electron microscopy. Observations were made of morphological changes within the epithelium, epithelial/ superficial lamina propria (SLP) junction, and the lamina propria of tissues treated with the PDL. Eight of nine patients were followed for a period of 9-25 months (mean, 18 months) with two recurrences that were retreated with awake-PDL and followed for an additional 8.3 and 9.5 months without recurrence. Vocal fold appearance returned to normal within 3-4 weeks posttreatment. RESULTS: Intraepithelial desmosome junctions were preferentially destroyed, and regional blood vessels were coagulated. The PDL consistently caused a separation of epithelial cells away from the basement membrane. CONCLUSIONS: The PDL allowed for both a surgical and a nonsurgical multimodality method for treatment of precancerous lesions with minimal effects on the SLP.

[Laryngectomy as a salvage procedure of the patients with massive postradiation injury of the larynx]. / Laryngektomia jako postepowanie ratujace u chorych z nasilonym odczynem popromiennym po radioterapii raka krtani.

INTRODUCTION: Author discusses problems and treatment principles of patients with massive postradiation injury, who had laryngectomy procedure as a result of insufficience of the farmacological treatment. MATERIAL AND METHODS: There were 12 patients who were performed laryngectomy as a treatment of massive postradiation injury of the larynx in the period 1975-2005. We suspected presence of persistent neoplasm with postradiation changes. Seven laryngectomies were performed after confirmation of the neoplasm in 1-3 biopsies. Three patients were treated operatively without this confirmation in spite of two biopsies which were negatively, and two patients were treated in this way without biopsies. RESULTS: Two patients had tomour free postlaryngectomy specimens in the histopathological examinations, and among 10 others the reccurence of the tumour after radiotherapy was present during the post-laryngectomy histopathological examinations. In 7 cases this reccurence was proved with massive postradiation injury in endoscopic biopsies before laryngectomy. DISCUSSION: Author presents his own problems and presents methods of treatment of the patients with massive postradiation injury of the larynx described in literature.

Combinatorial effects of geopropolis produced by Melipona fasciculata Smith with anticancer drugs against human laryngeal epidermoid carcinoma (HEp-2) cells.

The identification of natural products exerting a combined effect with therapeutic agents could be an alternative for cancer treatment, reducing the concentration of the drugs and side effects. Geopropolis (Geo) is produced by some stingless bees from a mixture of vegetable resins, gland secretions of the bees and soil. It has been used popularly as an antiseptic agent and to treat respiratory diseases and dermatosis. To determine whether Geo enhances the anticancer effect of carboplatin, methotrexate and doxorubicin (DOX), human laryngeal epidermoid carcinoma (HEp-2) cells were treated with Geo alone or in combination with each drug. Cell growth, cytotoxicity and apoptosis were evaluated using 3-(4,5-dimethyl thiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) release, and flow cytometry. Scratch assay was used to analyze cell migration and transmission electron microscopy to observe morphologic alterations. The influence of Geo on drug resistance was also investigated assessing P-glycoprotein (P-gp) action. Geo inhibited cell proliferation and migration. The combination Geo+DOX led to the highest cytotoxic activity and induced apoptosis, leading to loss of membrane integrity. Geo had no effect on P-gp-mediated efflux of DOX. Data indicate that Geo combined with DOX could be a potential clinical chemotherapeutic approach for laryngeal cancer treatment.

Large cell neuroendocrine carcinoma of the larynx: a case report and a review of the classification of this neoplasm.

This report describes a case of large cell neuroendocrine carcinoma (LCNEC) of the larynx. A 74 year old man who presented with otalgia underwent direct laryngoscopy with biopsy, which revealed an invasive poorly differentiated carcinoma. Laryngectomy with bilateral neck dissections revealed invasion of the pre-epiglottic space by the tumour, with metastases to bilateral lymph nodes (AJCC T3N2c). The tumour was characterised by large cells with vesicular chromatin and prominent nucleoli. The cells were arranged in organoid and trabecular patterns with a background of extensive necrosis and numerous mitotic figures. Immunohistochemical and ultrastructural analyses confirmed the neuroendocrine nature of the tumour. Metastatic disease was present in the liver, and the patient died within weeks of surgery. LCNEC carcinoma is a rare tumour of the larynx. Recognition at this site is essential so that proper patient management can be initiated.

Multivesicular bodies in HEp-2 cells are maturing endosomes.

Conventional fluorescence microscopy of fixed HEp-2 cells as well as video microscopy of living cells incubated with transferrin-Texas Red (Tf-TxR) for < 60 min revealed distinct punctuate endosomal structures. Quantitative ultrastructural analysis using horseradish peroxidase (HRP) and cationized gold as tracers showed that spherical multivesicular bodies (MVBs) were the predominant endocytic compartments in HEp-2 cells and that MVBs within 60 to 90 min matured into lysosomes still containing internal vesicles. The number of labeled MVBs increased continuously from 2.5 min to 30 min of tracer incubation. However, when the cells were pulsed for 5 min followed by 10 or 25 min chases, the number of labeled MVBs corresponded to that obtained after 5 min of continuous incubation. The diameter of labeled MVBs was largely constant with time, but the number of internal MVB vesicles increased. Thus, early or newly formed MVBs contained few internal vesicles, whereas late MVBs, that is to say, MVBs that have existed for some period of time, contained numerous internal vesicles, and finally a mixture of membranous material or myelin figures and vesicles. It is thus in principle possible to distinguish between early and late MVBs in HEp-2 cells on the basis of morphology. However, the difference in number of internal vesicles applies only to the entire MVB population; after only 2.5 to 5 min of incubation, MVBs with numerous internal vesicles could also be reached by internalized tracer. Concomitant with the gradual changes in morphology, the MVBs also showed a characteristic change in content of marker proteins as detected by immunogold labeling on ultracryosections. Hence, early MVBs with relatively few internal vesicles and typically reached by internalized tracers within 5 min contained transferrin receptors (TfRs). By contrast, MVBs with many internal vesicles and labeled after 60 min of incubation contained mannose-phosphate receptors (MPRs), and the MVBs with distinct membranous material or myelin figures in addition to the internal vesicles were enriched in the lysosome membrane protein lamp-1. Thus, there seems to be a gradual maturation of MVBs in HEp-2 cells.

Delivery to lysosomes in the human carcinoma cell line HEp-2 involves an actin filament-facilitated fusion between mature endosomes and preexisting lysosomes.

We have addressed the following question: what is the mechanism behind the delivery of internalized molecules from mature endosomes to lysosomes in HEp-2 cells, and which role does the cytoskeleton play in this process? Quantitative electron microscopy and immunogold labeling revealed that whereas the cytoskeleton was not of importance for endosome maturation, actin filaments facilitated fusion of mature endosomes with preexisting lysosomes. Delivery to lysosomal degradation was not dependent on protein synthesis as determined biochemically, but was reduced by cytochalasin D. Observations made by electron microscopy as well as by video microscopy of living cells showed that the concerted action of actin filaments and microtubules was responsible for the random distribution and movement of endocytic organelles throughout the cell. Actin microfilaments, however, seem to facilitate perinuclear clustering and frequent fusion of mature endosomes and lysosomes, while microtubules play a role in preventing formation of large lysosome aggregates by separating endosomes and lysosomes and moving them toward the cell periphery. Taken together, our data suggest that delivery of internalized molecules to lysosomal proteolysis takes place by fusion of mature endosomes with preexisting lysosomes and that actin microfilaments somehow facilitate this step.

Laryngeal paraganglioma. Case report with ultrastructural analysis and literature review.

Laryngeal paraganglioma is an infrequently reported tumor; only 16 examples have been recorded in the English literature. All but one laryngeal paraganglioma originated superiorly in the larynx; involvement of the ipsilateral aryepiglottic fold is common. Male patients predominate (11:5). The average age of patients at the time of diagnosis was 47 years, and symptoms had been present for an average duration of 5.8 years (range 6 months to 27 years). Attempted biopsy has resulted in significant hemorrhage in three cases. As illustrated by the present case, the Grimelius argyrophil stain is a useful diagnostic procedure. Electron microscopy confirmed the presence of neurosecretory granules with core diameters ranging from 110 to 140 nm. Surgical resection is the preferred treatment and has been possible in 14 cases; nine patients are alive and free of tumor for an average of 3 years. Compared to other head and neck paragangliomas, these have a more malignant course with a 25% mortality; tender subcutaneous metastases are commonly observed in these patients.

"Pseudosarcoma" of the larynx.

Polypoid epidermoid carcinoma of the larynx with a cellular, often atypical stroma has also been classified as pseudosarcoma, carcinosarcoma, pleomorphic carcinoma, or spindle cell sarcoma. The nature of the spindle-shaped stromal cells has clinical significance, but pathologists do not agree about the origin and potential of these cells. This paper describes two laryngeal tumors, one with an abundant osseous component in which light-microscopic, ultrastructural, and clinical features suggest the origin of these fusiform cells from reactive pluripotential mesenchyme. In a second case, atypical fusiform cells within the stroma show ultrastructural epithelial characteristics. These findings suggest a varied histogenesis for pseudosarcoma of the larynx and may explain divergent theories expressed in the literature.

Neuroendocrine carcinomas of the larynx. A study of two types, one of which mimics thyroid medullary carcinoma.

We studied 13 neuroendocrine carcinomas of the larynx. They constituted 59% of the 22 nonepidermoid carcinomas of the larynx seen at Memorial Hospital during a 45-year period, and for which adequate material was available for review. Four tumors were histologically identical to small cell carcinomas of the lung and were classified as small cell neuroendocrine carcinomas (SCNC). One case represents one of the original descriptions of the laryngeal SCNC. No SCNC was argyrophil, and of the three studied immunohistochemically, all contained neuron-specific enolase, one carcinoembryonic antigen (CEA) and one serotonin. Nine tumors were large cell carcinomas (LCNC). Eight LCNC were argyrophil, and all nine contained neuron-specific enolase, six calcitonin, four CEA, one HCG, two serotonin, and two somatostatin. The laryngeal neuroendocrine carcinomas commonly presented in chronic cigarette smokers with mean ages of 63 (SCNC) and 60 (LCNC), were not associated with other endocrine tumors, and proved highly fatal in spite of radical surgery and radiation therapy. At last follow-up only one patient was alive (after 13 months). Patients dying with SCNC survived a mean of 11 months, and those with LCNC, 36 months. To determine whether the laryngeal LCNC most closely resembles pulmonary neuroendocrine tumors, head and neck paragangliomas, or thyroid medullary carcinoma (TMC), they were histologically, histochemically, and immunohistochemically compared with control cases of each group. Overall, LCNC most closely resembles TMC, and given the frequency with which each presents as a neck mass, misinterpretation of one for the other is very possible. Evidence is provided suggesting that some LCNC have also been mistaken for the laryngeal paraganglioma.

Spindle-cell carcinoma of the upper aerodigestive tract mucosa. An immunohistologic and ultrastructural study of 18 biphasic tumors and comparison with seven monophasic spindle-cell tumors.

The histogenetic origin of the spindle-cell component of spindle-cell carcinoma of the head and neck mucosa remains controversial. The spindle cells have been considered a variant growth pattern of squamous-cell carcinoma, a non-neoplastic mesenchymal reaction, and a malignant admixture of epithelial and mesenchymal neoplasm. To evaluate the spindle-cell component, we studied 25 tumors (18 biphasic and seven monophasic) by utilizing the following: an avidin-biotin complex immunoperoxidase technique with a variety of antikeratin antibodies (AE1, AE3, CAM 5.2, 35BH11, and polyclonal Dako) and a monoclonal antivimentin antibody, and an avidin-biotin alkaline phosphatase double-labeling technique to detect coexpression of keratin and vimentin. The immunohistologic staining pattern was compared with electron-microscopic studies. Eight of 18 biphasic neoplasms contained immunoreactive keratin in the spindle-cell component that was distributed focally in a minority of cells in 3 tumors and diffusely throughout five of the neoplasms. Four of seven ulcerated monophasic spindle-cell tumors devoid of histologic squamous-cell carcinoma also were keratin positive, confirming epithelial differentiation. The majority of the spindle cells in all the tumors contained vimentin intermediate filaments. In three immunoperoxidase keratin positive biphasic tumors examined with alkaline phosphatase double labeling, occasional spindle cells were found that coexpressed keratin and vimentin and were interspersed with cells expressing either intermediate filament. Electron microscopy was performed on the spindle-cell component of 13 tumors, nine biphasic and four monophasic. Of the biphasic tumors, four were immunoperoxidase keratin positive; three of these showed epithelial differentiation by electron microscopy. Five biphasic tumors were keratin negative, and three tumors had epithelial differentiation by electron microscopy. Four monophasic spindle-cell tumors were immunoperoxidase keratin positive, and one of these had epithelial features by electron microscopy. Two monophasic tumors were keratin negative and without ultrastructural evidence of epithelial features. By using a combination of immunohistochemical and electron-microscopic observations, we identified evidence for epithelial differentiation in the spindled cells in 11 of 18 biphasic tumors and four of seven monophasic spindle-cell tumors.

The nuclear localization of NFkappaB and p53 is positively correlated with HPV16 E7 level in laryngeal squamous cell carcinoma.

The interaction between the HPV (human papilloma virus) 16 E7 and other cell growth factors, such as p53 and NFkappaB in laryngeal cancer is not clearly understood. The aim of this study was to examine the expression of these three proteins in tumor and non-tumor laryngeal tissues from patients with laryngeal squamous cell carcinoma. These three proteins were dominantly expressed in the nucleus and their levels were higher in the tumor tissue than in the non-tumor tissue, although the comparison between the tumor and non-tumor tissues of p53 staining did not reach significance. The intensity of the nuclear stain of E7 and p53 was stronger than that of p65, a subunit of NFkappaB. Correlation analysis revealed that there was a positive relationship between the level of HPV16 E7 and the expression of p65. The correlation between E7 and p53 was also significant, although to a lesser degree. The finding of nuclear localization of p65 suggests that NFkappaB is constantly activated in the laryngeal cancer cells, whereas the sequestration of p53 in the nucleus may represent a mutated form of p53, which is probably inactivated by HPV16 oncoproteins. In conclusion, this study suggests that the nuclear localization of NFkappaB and p53 may play a role in the development of human laryngeal squamous cell carcinoma infected with HPV16.

Detection of human papillomavirus in laryngeal lesions by in situ hybridization.

Human papillomavirus (HPV) is associated with human neoplasms of squamous epithelium. Squamous papillomas and verrucous carcinomas are two types of squamous neoplasms of the larynx that present difficult problems in differential diagnosis. Using in situ hybridization with biotinylated DNA probes, we examined benign squamous papillomas and verrucous squamous carcinomas of the larynx for the presence of HPV. Forty-two biopsy specimens from 18 patients with laryngeal papillomas and 11 biopsy specimens from seven patients with verrucous carcinomas were obtained from the files of Pennsylvania Hospital, Philadelphia, PA. Tissue sections were hybridized with an HPV DNA cocktail. The HPV-positive cases then were subtyped further with DNA probes specific for HPV subtypes 6/11, 16/18, and 31/33/35. All benign squamous papillomas (42 of 42) were positive for HPV subtype 6/11. None of the verrucous carcinomas contained demonstrable HPV (none of 11). Some of the squamous papillomas were recurrences, which shows the persistence of the virus. These results indicate that laryngeal papillomas may be related to HPV, but verrucous carcinomas are not.

Spindle cell carcinoma of the larynx.

The clinicopathological features of 14 laryngeal neoplasms consisting of spindle-shaped cells are presented. Light microscopy showed a variety of morphological patterns from that of pleomorphic sarcoma and fibrosarcoma to more loose vascular patterns. Immunohistochemistry revealed that the spindle-shaped cells had a positive keratin immunoreactivity in 8 of 14 cases, and also that some cases had a dual expression of keratin and vimentin filaments. Electron microscopy showed that spindle-shaped cells had epithelial ultrastructures. The results support the hypothesis that the spindle cell carcinomas are true carcinomas with mesenchymal metaplasia and that the spindle-shaped cells are part of the neoplasm and not benign, reactive fibroblasts. These lesions occurred mainly on the true vocal cords in elderly patients. The neoplasms were nearly all polypoid, and many also ulcerated. There is no significant difference in clinical behaviour between laryngeal spindle cell carcinomas and ordinary squamous cell carcinomas of the larynx, and the same treatment policy is therefore advocated. Being polypoid and therefore able to be surgically removed with relative ease, they may even present a more favourable clinical course.