Madanagopalan Ethunandan

Needle breakage following inferior alveolar nerve block: implications and management

Needle breakage following inferior alveolar nerve block is a rare complication in current dental practice. We report a case of delayed retrieval of a broken needle with the use of modern imaging modalities. In addition, possible causes of needle breakage and preventative measures, indications and timing of removal, localisation techniques and surgical approaches are discussed.

Aberrant expression of β-dystroglycan may be due to processing by matrix metalloproteinases-2 and -9 in oral squamous cell carcinoma

Dystroglycan (DG), a non-integrin adhesion molecule, is formed by two subunits, alpha- and beta-DG, which bind to extracellular matrix molecules and cytoskeleton. DG expression is frequently reduced in human cancers and has been related to tumor grade and aggressiveness. The exact proteolytic processing of beta-DG remains largely unknown. In this study, we investigated the correlation of beta-DG degradation with invasiveness in oral squamous cell carcinoma (OSCC) and its possible processing by matrix metalloproteinases (MMP). Immunohistochemical staining was used to assess beta-DG expression in 60 cases of OSCC. The effects of the MMP inhibitor 1,10-phenanthroline on tumour cell invasion and beta-DG degradation were investigated using in vitro invasion assays and immunoblot analysis. Co-immunoprecipitation and N-terminal sequencing were performed to determine the possible cleavage site of beta-DG by MMP. The alpha- and beta-DG expression was reduced or lost in OSCC. In four cell lines studied (SCC-4, SCC-9, SCC-15 and SCC-25), Western blot revealed a 30kDa fragment of beta-dystroglycan (beta-DG30) in addition to beta-DG itself. beta-DG degradation was almost abolished using 1,10-phenanthroline and there was a significant decrease in tumor cell invasion. The N-terminal sequence of beta-DG30 was detected as Ile-Asn-Thr-Asn, or Ile-Val-Thr-Gln. We conclude that beta-DG degradation may play a role both in OSCC invasion and metastasis. MMP activity seems to be one mechanism for beta-DG processing into beta-DG30.

Factors influencing the occurrence of multicentric and 'recurrent' Warthin's tumour: a cross sectional study.

The multicentric nature of Warthins tumour has been well recognised, though the factors predicting its occurrence and its influence on management remain speculative. In this cross sectional study, the authors analysed the presentation, management and outcome of solitary and multicentric Warthins tumour, treated in the maxillofacial unit and investigated factors that could influence the occurrence of multicentric and recurrent tumours. Warthins tumour was found in 24% (150/628) of patients presenting with parotid neoplasms and multicentric tumours were found in 13% (21/ 161) of parotidectomy specimens. Age, sex, side, site and smoking history were not predictors of multicentricity (P>0.40). Clinical examination (19%), imaging investigations (28%) and intra-operative palpation (33%) were poor at detecting multicentric tumours. Superficial parotidectomy was the most commonly performed operation. The recurrence rate was 0% in the solitary and 10% in the multicentric tumour group. Intra-operative rupture was not uncommon (11%), but was not associated with tumour recurrence (P= or >0.999). Incomplete excision (P=0.007) and multicentricity (P=0.026) were predictors of recurrence.

Primary epithelial submandibular salivary gland tumours – Review of management in a district general hospital setting

Primary epithelial submandibular gland (SMG) tumours are uncommon, accounting for 8-12% of all salivary gland neoplasms, and most studies come from large specialised centres. There is little published about the relative frequency and outcome of SMG tumours treated in general hospitals. A retrospective study from two district general hospitals over a 10 year period (1996-2005). Seventeen benign (68%) and eight malignant (32%) tumours were included. A painless mass was the most common presentation. Pain and paraesthesia were not pathognomonic of malignancy. Pleomorphic adenoma accounted for all 17 benign tumours and adenoid cystic carcinoma was the commonest malignant tumour. Fine needle aspiration cytology (FNAC) accurately identified 78% of the benign tumours but none of the malignant tumours. Pre-operative imaging was also unable to distinguish malignant from benign tumours. Incomplete excision was reported in 20% of cases and was more common for malignant tumours. It may be difficult to distinguish benign from malignant SMG tumours on clinical examination and pre-operative investigations. Any suspected submandibular tumour should be considered for early treatment even when FNAC is suggestive of a benign tumour.