A Case of HPV-Associated Oropharyngeal Squamous Cell Carcinoma with Block-Like, Partial Loss of p16 Expression.

BACKGROUND: Oropharyngeal squamous cell carcinoma is frequently associated with high-risk HPV infection, which confers a good prognosis. Immunohistochemistry for p16 is used as a surrogate for HPV status, but discrepant results are occasionally seen. Here, we report a case with a unique pattern of partial loss of p16. METHODS: A 63 year old male presented with a base of tongue nonkeratinizing squamous cell carcinoma and a large metastatic neck mass. The primary lesion and multiple regions of the metastatic mass were assessed with p16 immunohistochemistry, RNA in situ hybridization for high-risk HPV, and HPV16 genome sequencing. RESULTS: The primary lesion was p16 negative, and the metastatic neck mass had large, confluent regions that were either strongly p16 positive or entirely p16 negative. All of these regions were positive for high-risk HPV with identical HPV16 genomes. CONCLUSION: This unusual case illustrates a potential diagnostic pitfall, and it raises important questions regarding molecular mechanisms and prognostic implications of p16 staining in oropharyngeal squamous cell carcinoma.

Socio-economic factors and stage at presentation of head and neck cancer patients in Ottawa, Canada: a logistic regression analysis.

To determine if socio-economic status (SES) affects the stage at presentation of head and neck cancer (HNC) patients in Ottawa, Canada. To determine if the method of diagnosis affects the stage at presentation in these patients. We obtained data on SES, method of diagnosis, and stage at presentation for patients presenting to the head and neck cancer clinic at The Ottawa Hospital Regional Cancer Centre (TORCC). We performed a logistic regression analysis using stage at presentation as the dependent variable. We found no statistically significant association between average family income (by postal code) and stage at presentation. We found that oral cancers presented at a later stage compared with other HNCs but that who made the diagnosis was an important factor. Oral cancers diagnosed by a dentist had 3.44 times the odds of being at a later stage than other HNCs (CI 1.01-11.96), but oral cancers diagnosed by other means had 11.42 times the odds of being at a later stage than other HNCs. We found that male patients presented at a later stage than female patients (OR 2.62, CI 1.03-6.63). Finally, former smokers had about 1/3 the odds of presenting at a later stage than current smokers (OR 0.33, CI 0.13-0.84) although nonsmokers were not significantly less likely than current smokers to present later (OR 0.47, CI 0.17-1.32). We found no evidence that in Ottawa, Canada patients of a lower SES with HNC presented at an different stage than patients with higher SES. We found that patients presenting with oral cancers presented at an earlier stage if they were diagnosed by a dentist.

The effect of wall thickness on the response of a spherical ionization chamber.

Air-filled ionization chambers are used widely for radiation dosimetry. For some applications it is important to know the effect on the chamber response of photon attenuation and scattering in the chamber walls. Traditionally, the wall effect is determined by measuring the chamber response as a function of wall thickness and extrapolating linearly to zero thickness. We have constructed a spherical graphite chamber with variable wall thickness. The change in the chamber response with wall thickness has been measured in a 137Cs gamma-ray beam. Our data show that the change in response is not linear with wall thickness, in agreement with the theoretical prediction of Bielajew (1990 Med. Phys. 17 583-7). A linear versus non-linear extrapolation of the measured data to zero wall thickness leads to a difference of almost 1% in the estimate of the wall correction factor, Kw. The value of Kw obtained using the non-linear extrapolation is in good agreement with the result obtained using Monte Carlo techniques.

Optimal treatment of descending necrotising mediastinitis.

BACKGROUND: Descending necrotising mediastinitis is caused by downward spread of neck infection and has a high fatality rate of 31%. The seriousness of this infection is caused by the absence of barriers in the contiguous fascial planes of neck and mediastinum. METHODS: The recent successful treatment of seven adult patients with descending necrotising mediastinitis emphasises the importance of optimal early drainage of both neck and mediastinum and prolonged antibiotic therapy. The case is also presented of a child with descending necrotising mediastinitis, demonstrating the rapidity with which the infection can develop and lead to death. Twenty four case reports and 12 series of adult patients with descending necrotising mediastinitis published since 1970 were reviewed with meta-analysis. In each case of confirmed descending necrotising mediastinitis the method of surgical drainage (cervical, mediastinal, or none) and the survival outcome (discharge home or death) were noted. The chi 2 test of statistical significance was used to detect a difference between cases treated with cervical drainage alone and cases where mediastinal drainage was added. RESULTS: Cervical drainage alone was often insufficient to control the infection with a fatality rate of 47% compared with 19% when mediastinal drainage was added (p < 0.05). CONCLUSIONS: Early combined drainage with neck and chest incisions, together with broad spectrum intravenous antibiotics, should be considered standard care for this disease.

Nasal fossa dimensions in normal and nasally obstructed neonates and infants: preliminary study.

Computed tomography (CT) is a valuable imaging tool in the examination of neonates and infants with nasal obstruction. At present, however, it is difficult to quantitatively evaluate the nasal fossa with CT as normative data and the relative significance of individual nasal fossa dimensions have not been established. A standardized CT image was proposed, and performed on a prospective cohort of 56 infants up to 1 year of age. A parental questionnaire was used to identify infants with nasal obstruction. Normative data for four nasal fossa dimensions are presented and analyzed. The statistical validity of these dimensions in the diagnosis of nasal obstruction was examined; only the maximal posterior bony diameter showed a significant difference between normal and nasally obstructed infants (t-test, P = 0.05). Examples of CT findings in the above-mentioned cases as well as past cases of "choanal stenosis' are demonstrated.