John Diks identifies epimucocytes
- Pathologist John Effat Bacilious Diks and colleagues reported a new quantitative review of salivary gland needle aspirates that defines “epimucocytes” and measures how well those cells flag mucoepidermoid carcinoma. - In 95 aspirates reviewed from 2002 to 2021, epimucocytes were the most sensitive single feature at 0.90, while a combined feature set reached 91% specificity and a positive likelihood ratio of 8.9. - The study adds numbers to a diagnosis that often depends on pattern recognition alone and overlaps with tumors that can trigger MAML2 molecular testing. (wiley.com)
A pathologist’s microscope exam often works like visual pattern matching, and John Diks’ new paper tries to put numbers on that process for one salivary gland cancer. (wiley.com) The cancer is mucoepidermoid carcinoma, a malignant tumor made of varying mixes of mucous, epidermoid, and intermediate cells. Its shifting appearance can make fine-needle aspiration diagnoses difficult before surgery. (pathologyoutlines.com) (wiley.com) Fine-needle aspiration is a thin-needle sampling test, and cytology is the slide-based readout of those cells. Diks and co-authors treated each cell feature on those slides like a diagnostic test that can be measured for sensitivity, specificity, and likelihood ratios. (wiley.com) Their retrospective study reviewed 95 salivary gland aspirates collected from 2002 through 2021 in cases where mucoepidermoid carcinoma was in the differential diagnosis. Follow-up histology confirmed 49 of the 95 as true mucoepidermoid carcinoma. (wiley.com) The paper’s new term is “epimucocyte,” defined as a mucin-filled vacuolated cell with a dense squamoid rim of cytoplasm. Two cytopathologists scored 16 predefined features, including extracellular mucin, mucocytes, epimucocytes, and non-mucinous empty vacuolated cells. (wiley.com) Epimucocytes were the most sensitive single feature at 0.90, meaning they showed up in most confirmed mucoepidermoid carcinoma cases. Intermediate cells were the most specific single feature at 0.94, while extracellular mucin, mucocytes, and epidermoid cells were also predictive. (wiley.com) The best-performing combination was any mucinous feature — epimucocytes, mucocytes, or extracellular mucin — plus either intermediate or squamous cells. That combination reached 91% specificity with a positive likelihood ratio of 8.9. (wiley.com) That matters because mucoepidermoid carcinoma is already known for morphologic heterogeneity, and older cytology studies have described frequent interpretive pitfalls. Molecular confirmation can help in hard cases because many mucoepidermoid carcinomas carry MAML2 rearrangements. (pmc.ncbi.nlm.nih.gov 1) (pmc.ncbi.nlm.nih.gov 2) Mayo Clinic Laboratories says MAML2 rearrangements are detectable in about 80% to 85% of mucoepidermoid carcinomas and can support the diagnosis when paired with pathology review. The Diks paper does not replace that testing; it gives cytopathologists a more explicit way to decide which aspirates look most suspicious first. (oncology.testcatalog.org) (wiley.com) The article was received on January 13, 2026, accepted on April 11, 2026, and published in *Diagnostic Cytopathology* as an open-access original study. Its closing claim is narrower than the hype around it: the authors say they provide a standardized definition for epimucocytes and a first quantitative estimate of their diagnostic value. (wiley.com)
