Eosinophils as a marker for invasion in cervical squamous neoplastic lesions.

A study of eosinophils associated with cervical neoplastic squamous epithelium was undertaken to determine whether their presence is a marker for invasion. Forty cervical incisional biopsy specimens of high-grade squamous intraepithelial neoplasia (HSIL), 12 with an element of invasive carcinoma, and 2 of HSIL suspicious for invasion, and follow-up excisional specimens of 27 cases of HSIL and 6 of microinvasive and invasive carcinoma were reviewed. In both incisional biopsy and excisional specimens, the presence of >or=5 eosinophils/high-power fields (hpf) and >or=10 eosinophils/10 hpf were both highly significantly associated with invasion with a high degree of specificity and positive predictive value, whereas counts below these thresholds had a high negative predictive value. The authors propose: 1) eosinophil counts in cervical incisional biopsy specimens of >or=5/hpf and/or >or=10/10 hpf warrant a note of caution that invasion may be present even when none is identified in the specimen by conventional criteria; 2) eosinophil counts of >or=5/hpf and/or >or=10/10 hpf in excisional biopsy and hysterectomy specimens should raise the suspicion of invasion in cases in which only HSIL is identified in the initial sections, and warrant additional sections and/or levels to search for invasion; and 3) the above eosinophil counts may provide supportive evidence for invasion in cases with equivocal invasion by conventional criteria.