We sought to classify endocervical adenocarcinomas (ECAs) based on morphologic features linked to etiology (ie, human papillomavirus [HPV] infection), unlike the World Health Organization 2014 classification. The International Endocervical Adenocarcinoma Criteria and Classification (IECC criteria), described herein, distinguishes between human papillomavirus-associated adenocarcinoma (HPVA), recognized by the presence of luminal mitoses and apoptosis seen at scanning magnification, and no or limited HPVA features (nonhuman papillomavirus-associated adenocarcinoma [NHPVA]). HPVAs were then subcategorized based on cytoplasmic features (mostly to provide continuity with preexisting classification schemes), whereas NHPVAs were subclassified based on established criteria (ie, gastric-type, clear cell, etc.). Complete slide sets from 409 cases were collected from 7 institutions worldwide. Tissue microarrays representing 297 cases were constructed; immunohistochemistry (p16, p53, vimentin, progesterone receptor) and chromogenic in situ hybridization using an RNA-based probe set that recognizes 18 varieties of high-risk HPV were performed to validate IECC diagnoses. The 5 most common IECC diagnoses were usual-type (HPVA) (73% of cohort), gastric-type (NHPVA) (10%), mucinous adenocarcinoma of HPVA type, including intestinal, mucinous not otherwise specified, signet-ring, and invasive stratified mucin-producing carcinoma categories (9%), clear cell carcinoma (NHPVA) (3%) and adenocarcinoma, not otherwise specified (2%). Only 3 endometrioid carcinomas were recognized and all were NHPVA. When excluding cases thought to have suboptimal tissue processing, 90% and 95% of usual-type IECC cases overexpressed p16 and were HPV, whereas 37% and 3% of NHPVAs were p16 and HPV, respectively. The 1 HPV gastric-type carcinoma was found to have hybrid HPVA/NHPVA features on secondary review. NHPVA tumors were larger and occurred in significantly older patients, compared with HPVA tumors (P<0.001). The high-risk HPV chromogenic in situ hybridization probe set had superior sensitivity, specificity, and positive and negative predictive values (0.955, 0.968, 0.992, 0.833, respectively) compared with p16 immunohistochemistry (0.872, 0.632, 0.907, 0.545, respectively) to identify HPV-related usual carcinoma and mucinous carcinoma. IECC reliably segregates ECAs into HPVA and NHPVA types using morphology alone. This study confirms that usual-type ECAs are the most common type worldwide and that mucinous carcinomas comprise a mixture of HPVA and NHPVA, with gastric-type carcinoma being the major NHPVA type. Endometrioid and serous carcinomas of the endocervix are extraordinarily rare. Should clinical outcomes and genomic studies continue to support these findings, we recommend replacement of the World Health Organization 2014 criteria with the IECC 2017.

The International Endocervical Adenocarcinoma Criteria and Classification was developed to separate endocervical adenocarcinomas (ECAs) into 2 main categories on the basis of morphology such as human papilloma virus-associated (HPVA) and non-human papilloma virus-associated adenocarcinomas. We aimed to improve the diagnostic accuracy of International Endocervical Adenocarcinoma Criteria and Classification by performing a comprehensive immunohistochemical evaluation and constructing objective immunohistochemical-based algorithms for the classification of these tumors. Tissue microarrays were constructed from 297 of 409 cases used to develop the original classification. Immunostains included p16, p53, estrogen receptor (ER), progesterone receptor, androgen receptor, Vimentin, CK7, CK20, HER2, HIK1083, MUC6, CA-IX, SATB2, HNF-1beta, napsin A, PAX8, CDX2, GATA3, p63, p40, and TTF-1. High-risk human papilloma virus (HR-HPV) was detected by in situ hybridization (ISH) using probes against E6 and E7 mRNA expressed in 18 different virus types. Vimentin, ER, and progesterone receptor were expressed in a significant minority of ECAs, mostly HPVAs, limiting their use in differential diagnosis of endometrioid carcinoma when unaccompanied by HPV-ISH or p16. HR-HPV ISH had superior sensitivity, specificity, and negative and positive predictive values compared with p16, as published previously. HNF-1beta did not have the anticipated discriminatory power for clear cell carcinoma, nor did MUC6 or CA-IX for gastric-type carcinoma. HNF-1beta and napsin A were variably expressed in clear cell carcinoma, with HNF-1beta demonstrating less specificity, as it was ubiquitously expressed in gastric-type carcinoma and in the majority of HPV-associated mucinous (predominantly intestinal-type and invasive ECA resembling stratified mucin-producing intraepithelial lesion [iSMILE]) and usual-type carcinomas. HIK1083 was expressed in nearly half of gastric-type carcinomas, but not in the vast majority of other subtypes. GATA3 was positive in 10% of usual-type adenocarcinomas and in single examples of other subtypes. Rare gastric-type and HPVA mucinous carcinomas displayed HER2 overexpression. Androgen receptor was positive in 6% of usual-type adenocarcinomas. Aberrant p53 expression was found in only 3.6% of usual-type HPVA carcinomas, but it was more prevalent in mucinous (intestinal type and iSMILE) HPVAs and non-human papilloma virus-associates (particularly in gastric-type carcinoma,>50% of cases). The following diagnostic classification algorithms were developed with the above data. Carcinomas without overt cytoplasmic mucin (endometrioid, usual-type endocervical, clear cell, and mesonephric carcinomas) can be subclassified using HR-HPV ISH, ER, and GATA3, whereas carcinomas with easily appreciated cytoplasmic mucin (endometrioid carcinoma with mucinous features, HPVA mucinous, and gastric-type carcinomas) can be subclassified with HR-HPV ISH and ER.

The International Endocervical Adenocarcinoma Criteria and Classification (IECC) categorizes endocervical adenocarcinomas (ECAs) based on morphological features linked to etiology (i.e. human papilloma virus (HPV) infection), resulting in separation of ECAs into HPV-associated (HPVA) and unassociated, or non-HPVA (NHPVA) types. NHPVAs are reported to be large and

Application of the Silva system is only relevant in HPVA cervical adenocarcinoma.

Although 2014 World Health Organization criteria require unequivocal glandular and squamous differentiation for a diagnosis of cervical adenosquamous carcinoma, in practice, adenosquamous carcinoma diagnoses are often made in tumors that lack unequivocal squamous and/or glandular differentiation. Considering the ambiguous etiologic, morphological, and clinical features and outcomes associated with adenosquamous carcinomas, we sought to redefine these tumors. We reviewed slides from 59 initially diagnosed adenosquamous carcinomas (including glassy cell carcinoma and related lesions) to confirm an adenosquamous carcinoma diagnosis only in the presence of unequivocal malignant glandular and squamous differentiation. Select cases underwent immunohistochemical profiling as well as human papillomavirus (HPV) testing by in situ hybridization. Of the 59 cases originally classified as adenosquamous carcinomas, 34 retained their adenosquamous carcinoma diagnosis, 9 were reclassified as pure invasive stratified mucin-producing carcinomas, 10 as invasive stratified mucin-producing carcinomas with other components (such as HPV-associated mucinous, usual-type, or adenosquamous carcinomas), and 4 as HPV-associated usual or mucinous adenocarcinomas with benign-appearing squamous metaplasia. Two glassy cell carcinomas were reclassified as poorly differentiated usual-type carcinomas based on morphology and immunophenotype. There were significant immunophenotypic differences between adenosquamous carcinomas and pure invasive stratified mucin-producing carcinomas with regard to HPV (p<0.0001), PAX8 (p=0.038; more in adenosquamous carcinoma), p40 (p<0.0001; more in adenosquamous carcinoma), p63 (p=0.0018; more in adenosquamous carcinoma) and MUC6 (p<0.0001; less in adenosquamous carcinoma), HNF1beta (p=0.0023), vimentin (p=0.0003), p53 (p=0.0004), and CK7 (p=0.0002) expression. Survival outcomes were similar between all groups. adenosquamous carcinomas should be diagnosed only in the presence of unequivocal malignant glandular and squamous differentiation. The two putative glassy cell carcinomas studied did not meet our criteria for adenosquamous carcinoma, and categorizing them as such should be reconsidered.

Invasive stratified mucin-producing carcinoma (ISMC) is a recently described tumor with similar morphology to the stratified mucin-producing intraepithelial lesion. Stratified mucin-producing intraepithelial lesion and ISMC likely arise from human papillomavirus (HPV)-infected reserve cells in the cervical transformation zone that retain their pluripotential ability to differentiate into various architectural and cytologic patterns. This is important, as small studies have suggested that ISMC may be a morphologic pattern associated with more aggressive behavior than usual HPV-associated adenocarcinoma. We sought to study the morphologic spectrum of this entity and its associations with other, more conventional patterns of HPV-associated carcinomas. Full slide sets from 52 cases of ISMC were reviewed by an international panel of gynecologic pathologists and classified according to the new International Endocervical Criteria and Classification system. Tumors were categorized as ISMC if they demonstrated stromal invasion by solid nests of neoplastic cells with at least focal areas of mucin stratified throughout the entire thickness, as opposed to conventional tall columnar cells with luminal gland formation. Tumors comprising pure ISMC, and those mixed with other morphologic patterns, were included in the analysis. Twenty-nine pure ISMCs (56%) and 23 ISMCs mixed with other components (44%) were identified. Other components included 13 cases of usual-type adenocarcinoma, 6 adenosquamous carcinoma, 3 mucinous-type adenocarcinoma, 1 high-grade neuroendocrine carcinoma. ISMC displayed architectural diversity (insular, lumen-forming, solid, papillary, trabecular, micropapillary, single cells) and variable cytologic appearance (eosinophilic cytoplasm, cytoplasmic clearing, histiocytoid features, glassy cell-like features, signet ring-like features, bizarre nuclei, squamoid differentiation). Awareness of the spectrum of morphologies in ISMC is important for accurate and reproducible diagnosis so that future studies to determine the clinical significance of ISMC can be conducted.

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Rationale:Nail bed solitary neurofibroma is an extremely rare tumor, with only 9 cases recorded in the literature so far.Patient concern:We present the case of a 42-year-old female patient, with a history of a slowly growing tumor in the nail bed of the left index and no clinical features of type I neurofibromatosis.Diagnosis:Nail bed solitary neurofibroma.Intervention:The tumor was surgically removed and the pathology examination established the diagnosis of neurofibroma.Outcomes:The postoperative outcome was good, with no recurrence 12 months after surgery.Lessons:We present the rarity of this type of tumor localized in the nail bed, taking into consideration the only 9 cases recorded in the literature. Nail bed solitary neurofibroma should be also included in the differential diagnosis of a nail bed tumor.