PIK3CA mutations are believed to contribute to the pathogenesis of human papillomavirus (HPV)-associated head and neck squamous cell carcinomas (HNSCC). This study aims to establish the frequency of PIK3CA mutations in a Portuguese HNSCC cohort and to determine their association with the HPV status and patient survival. A meta-analysis of scientific literature also revealed widely different mutation rates in cohorts from different world regions and a trend towards improved prognosis among patients with PIK3CA mutations. DNA samples were available from 95 patients diagnosed with HNSCC at the Portuguese Institute of Oncology in Lisbon between 2010 and 2019. HPV status was established based on viral DNA detected using real-time PCR. The evaluation of PIK3CA gene mutations was performed by real-time PCR for four mutations (H1047L; E542K, E545K, and E545D). Thirty-seven cases were found to harbour PIK3CA mutations (39%), with the E545D mutation (73%) more frequently detected. There were no significant associations between the mutational status and HPV status (74% WT and 68% MUT were HPV (+); p = 0.489) or overall survival (OS) (3-year OS: WT 54% and MUT 65%; p = 0.090). HPV status was the only factor significantly associated with both OS and disease-free survival (DFS), with HPV (+) patients having consistently better outcomes (3-year OS: HPV (+) 65% and HPV (−) 36%; p = 0.007; DFS HPV (+) 83% and HPV (−) 43%; p = 0.001). There was a statistically significant interaction effect between HPV status and PIK3CA mutation regarding DFS (Interaction test: p = 0.026). In HPV (+) patients, PIK3CA wild-type is associated with a significant 4.64 times increase in the hazard of recurrence or death (HR = 4.64; 95% CI 1.02–20.99; p = 0.047). Overall, PIK3CA gene mutations are present in a large number of patients and may help define patient subsets who can benefit from therapies targeting the PI3K pathway. The systematic assessment of PIK3CA gene mutations in HNSCC patients will require further methodological standardisation.

Salivary gland tumor classification encompasses a vast list of benign and malignant neoplasms. Their morphological diversity is recognized not only between different entities but also within individual tumors. Tumor categories as described by the World Health Organization reflect, in part, a true genetic heterogeneity (e.g., translocations involving CRTC1 and CRTC3-MAML2 genes in mucoepidermoid carcinoma and MYB-NFIB fusion in adenoid cystic carcinoma). Carcinoma ex pleomorphic adenoma shows diversity in its histological appearance, but recurrent rearrangements on PLAG1 and HMGA2 are common to its benign precursor. More recently, new categories have been defined, like secretory carcinoma with the t(12;15) (p13;q25) ETV6-NTRK3 translocation and clear-cell carcinoma with EWSR1-ATF1 fusion. Recent studies on cribriform adenocarcinoma of minor salivary gland origin and epithelial-myoepithelial carcinoma point to a correlation with their morphological features. All of these advances show that the search of a histogenetic and genetic basis for salivary gland tumors is helping to clarify morphological categories and unraveling new ones. Nevertheless, currently morphology is still the hallmark of tumor classification and the gold standard. The therapeutic options for advanced tumors remain very limited but the discovery of translocation-generated gene fusions and increased knowledge of the genomic information of salivary gland tumors is creating opportunities for the development of specific targeted therapies.

Mucoceles of the appendix are rare and can have quite variable imaging and clinical presentations, sometimes mimicking an adnexal mass. The underlying cause can be neoplastic or non-neoplastic. The typical imaging appearance of a mucocele of the appendix is that of a cystic structure with a tubular morphology. This structure is defined by having a blind-ending and being contiguous with the cecum. Radiologists should be familiar with key anatomical landmarks and with the various imaging features of mucoceles of the appendix, in order to provide a meaningful differential diagnosis of a lesion in the right lower abdominal quadrant. In addition, a neoplastic mucocele can rupture, resulting in pseudomyxoma peritonei, which will change the prognosis dramatically. Therefore, prompt diagnostic imaging is crucial.