Salvage neck surgery in recurrent nodal NPC: Do all patients require a comprehensive neck dissection in the modern MRI era?

OBJECTIVE: The standard treatment for regional failure in nasopharyngeal carcinoma (NPC) is the radical neck dissection (RND). Our study sought to determine if magnetic resonance imaging (MRI) may accurately predict nodal involvement to allow selected levels of neck dissection to be preserved. STUDY DESIGN AND SETTING: We analysed retrospectively all NPC patients in our centre undergoing neck dissections as salvage therapy for nodal recurrence. Nodal involvement based on the preoperative MRI was assessed and compared with postoperative histopathology. METHODS: This is a retrospective study conducted on patients in our centre with recurrent NPC from February 2002 to February 2017. Patients were identified from the database of the otolaryngology oncology division at our institution. Of these, 28 patients met all our inclusion and exclusion criteria. We calculated sensitivity and specificity as well as average number of nodes per patient. RESULTS: In our study, we calculated the false negative and false positive rates of preoperative MRI neck by levels. Overall sensitivity of MRI picking up disease by level was 76% and specificity was 86%. CONCLUSION: Based on our study, we will be missing a total of 10 (7.1%) diseased neck levels in eight (28.5%) patients. MRI alone, therefore, does not provide enough information to allow safe selective preservation of neck levels in surgical salvage of neck recurrences in NPC.

Skull base osteomyelitis secondary to malignant otitis externa mimicking advanced nasopharyngeal cancer: MR imaging features at initial presentation.

PURPOSE: Skull base osteomyelitis (SBOM) is an inflammatory process which often arises from malignant otitis externa (MOE); the diffuse skull base and adjacent soft tissue involvement may be mistaken at initial imaging for advanced nasopharyngeal carcinoma (NPC), especially if there is no prior knowledge of MOE, direct spread from the sphenoid sinus or in atypical presentations of MOE. This study aims to evaluate imaging features on MR that may differentiate SBOM from NPC. MATERIALS AND METHODS: The MR examinations of 26 patients diagnosed with SBOM between January 1996 and January 2013 were retrospectively reviewed. Comparison was also made with the MR images of 22 consecutive patients with newly diagnosed advanced T3 and T4 NPC between July 2011 and August 2012. Imaging features in both conditions were compared, including the presence of a nasopharyngeal bulge, nasopharyngeal mucosal irregularity, lateral extension, architectural distortion (or lack thereof), increased T2 signal and enhancement patterns. RESULTS: The most prevalent findings in SBOM were lateral extension, increased T2 signal in adjacent soft tissues, lack of architectural distortion and enhancement greater than or equal to mucosa. The combination of these 4 findings was found to best differentiate SBOM from advanced NPC, and found to be statistically significant (p<0.001). CONCLUSION: We suggest that the combination of lateral extension, increased T2 signal, lack of architectural distortion and enhancement greater than or equal to mucosa is helpful in differentiating SBOM from advanced NPC.

Superior cervical ganglion mimicking retropharyngeal adenopathy in head and neck cancer patients: MRI features with anatomic, histologic, and surgical correlation.

INTRODUCTION: To describe the unique MRI findings of superior cervical ganglia (SCG) that may help differentiate them from retropharyngeal lymph nodes (RPLNs). METHODS: A retrospective review of post-treatment NPC patients from 1999 to 2012 identified three patients previously irradiated for NPC that were suspected of having recurrent nodal disease in retropharyngeal lymph nodes during surveillance MRI. Subsequent surgical exploration revealed enlarged SCG only; no retropharyngeal nodal disease was found. A cadaveric head specimen was also imaged with a 3T MRI before and after dissection. In addition, SCG were also harvested from three cadaveric specimens and subjected to histologic analysis. RESULTS: The SCG were found at the level of the C2 vertebral body, medial to the ICA. They were ovoid on axial images and fusiform and elongated with tapered margins in the coronal plane. T2-weighted (T2W) signal was hyperintense. No central elevated T1-weighted (T1W) signal was seen within the ganglia in non-fat-saturated sequences to suggest the presence of a fatty hilum. Enhancement after gadolinium was present. A central "black dot" was seen on axial T2W and post-contrast images in two of the three SCG demonstrated. Histology showed the central black line was comprised of venules and interlacing neurites within the central portion of the ganglion. CONCLUSIONS: The SCG can be mistaken for enlarged RPLNs in post-treatment NPC patients. However, there are features which can help differentiate them from RPLNs, preventing unnecessary therapy. These imaging findings have not been previously described.

Anaesthetic considerations of temporomandibular joint ankylosis with obstructive sleep apnoea: a case report.

The peroperative management of a 4 1/2 yr old child having bilateral recurrent temporomandibular joint (TMJ) ankylosis and obstructive sleep apnoea (OSA) is presented here. From the anaesthesiologist's point of view, the patient demands special considerations as regards difficulty in intubation, high sensitivity to all central depressant drugs, awake extubation, and post-operative maintenance of a clear airway. It is to be concluded that these conditions call for strict adherence to the basic principles of airway management and close observation extending into the post-operative period.

Diagnosing features of Jacobson's nerve schwannoma.

Jacobson's nerve schwannoma is a rare middle ear tumour presenting as a mass along the cochlear promontory. It can be differentiated from other masses along the promontory based on clinical findings, and computed tomography and magnetic resonance imaging features. For small-sized masses, it is possible to differentiate the various middle ear schwannomas from one another. We present the case of a 40-year-old woman with a ten-year history of left hearing loss who was diagnosed with Jacobson's nerve schwannoma.

The Effect of organic nitrogen sources on recombinant glucoamylase production by Aspergillus niger in chemostat culture.

Aspergillus niger B1, a recombinant strain carrying 20 extra copies of the native glucoamylase gene, was grown in glucose-limited chemostat cultures supplemented with various organic nitrogen sources (dilution rate 0.12 +/- 0.01 h(-1), pH 5.4). In cultures supplemented with l-alanine, l-methionine, casamino acids, or peptone, specific glucoamylase (GAM) production rapidly decreased to less than 20% of the initial level. Reducing the pH of the culture to 4.0 resulted in stable GAM production for up to 400 h. Morphological mutants (a light brown and a dark brown mutant) appeared in each fermentation and generally displaced B1. Light brown mutants had higher selection coefficients relative to B1 than dark brown mutants and became the dominant strain in all fermentations except those maintained at pH 4.0. Several mutants isolated from these cultures had reduced ability to produce GAM in batch culture, although few had lost copies of the glaA gene. Some mutants had methylated DNA.

Production of tissue plasminogen activator (t-PA) in Aspergillus niger.

A protease-deficient strain of Aspergillus niger has been used as a host for the production of human tissue plasminogen activator (t-PA). In defined medium, up to 0.07 mg t-PA (g biomass)(-1) was produced in batch and fed-batch cultures and production was increased two- to threefold in two-phase batch cultures in which additional glucose was provided as a single pulse at the end of the first batch growth phase. Production was increased [up to 1.9 mg t-PA (g biomass)(-1)] by the addition of soy peptone to the defined medium. The rate of t-PA production in batch cultures supplemented with soy peptone (0.2 to 0.6 mg t-PA L(-1) h(-1)) was comparable to rates observed previously in high-producing mammalian or insect cell cultures. In glucose-limited chemostat culture supplemented with soy peptone, t-PA was produced at a rate of 0.7 mg t-PA L(-1) h(-1). Expression of t-PA in A. niger resulted in increased expression of genes (bipA, pdiA, and cypB) involved in the unfolded protein response (UPR). However, when cypB was overexpressed in a t-PA-producing strain, t-PA production was not increased. The t-PA produced in A. niger was cleaved into two chains of similar molecular weight to two-chain human melanoma t-PA. The two chains appeared to be stable for at least 16 h in culture supernatant of the host strain. However, in general, <1% of the t-PA produced in A. niger was active, and active t-PA disappeared from the culture supernatant during the stationary phase of batch cultures, suggesting that the two-chain t-PA may have been incorrectly processed or that initial proteolytic cleavage occurred within the proteolytic domain of the protein. Total t-PA (detected by enzyme-linked immunoassay) also eventually disappeared from culture supernatants, confirming significant extracellular proteolytic activity, even though the host strain was protease-deficient.