Redefining and capturing pre-analytic deficiencies in an anatomical pathology laboratory: a quality improvement initiative.

Pre-analytical deficiencies (PADs) are a major source of errors in anatomical pathology, accounting for about 70% of laboratory deficiencies. These can lead to incorrect diagnoses, delayed treatments, and increased healthcare costs. As part of a quality improvement initiative, we retrospectively identified and characterized 237 PADs documented over a 1-year period in a tertiary care academic center. The most common PADs were errors in specimen procurement (56%), handling of samples within the lab (16%), accessioning (10%), incomplete requisitions (9%), and transportation-related issues (7%). Strategies were then devised to mitigate these errors. Categorization of pre- and intra-laboratory PADs was refined into eight categories (collection, requisition, specimen container, transportation, receiving, accessioning, preparation, and communications) in the laboratory information system. Mandatory PAD documentation was implemented for accessioning staff. Post-implementation, prospective analysis identified that the most common PADs were related to surgical requisitions (75%). Among these, missing ordering physician's signature was the most common, accounting for 67.7% of requisition-related PADs and 50.8% of all PADs. Other common PADs included incomplete information of specimens, clinical information, patient information, physician information, source location, collection time, incorrect requisition forms, and illegible handwritten information. This study highlights the importance of identifying and addressing PADs in the anatomical pathology laboratory setting as well as the potential benefits of implementing standardized documentation and quality improvement processes to address these deficiencies.

Role of HPV in the Prediction of Persistence/Recurrence After Treatment for Cervical Precancer.

OBJECTIVES: (1) To determine the role of human papillomavirus (HPV) testing after excisional treatment of cervical precancer. (2) To determine clinical factors associated with persistence of cervical precancer post-treatment. METHODS: A retrospective chart review was conducted including patients who had a loop electrosurgical excision procedure (LEEP) for cervical precancer (cervical intraepithelial neoplasia 3/adenocarcinoma in situ/high-grade squamous intraepithelial lesions [HSIL]). All patients treated between 2016 and 2018 at a tertiary centre colposcopy unit were included. Persistence/recurrence of disease was defined as high-grade cytology or histology identified during the time of follow-up. Univariate and multivariate regression models were performed to identify factors associated with persistence/recurrence and HPV positivity at exit testing. RESULTS: A total of 284 patients were included. The median follow-up time was 19 months. Of the LEEP specimens, 90.8% (n = 258) demonstrated HSIL and 3.9% (n = 11) had adenocarcinoma in situ. 28.5% (n = 81) of the LEEP specimens had positive margins. In follow-up, 72.9% had negative cytology, 17.6% had atypical squamous cells of undetermined significance/low-grade SIL, 1.8% had atypical squamous cells, HSIL cannot be excluded/low-grade SIL-H, and 6.7% had HSIL. At the final follow-up, 27.8% (n = 79) were HPV+. Overall rate of persistence/recurrence was 11.3% (n = 32); median time to persistence/recurrence was 6.5 months. Multivariate regression models demonstrated that follow-up HPV positivity (OR = 22.0) and positive margins (OR = 3.7) were significantly associated with persistence/recurrence. Similarly, in univariate regression models, positive margins were significant (OR = 2.2) for predicting HPV positivity in exit testing. CONCLUSIONS: Persistence/recurrence of precancer can occur due to incomplete treatment of lesions by local excision and by the persistence of HPV infection. Surveillance strategies for women treated for cervical precancer require a risk-based approach and should rely on HPV testing.

Cytohistologic immunohistochemical correlation of epithelial tubo-ovarian neoplasms: Can cell blocks substitute for tissue?

BACKGROUND: Cytologic specimens often represent the initial diagnostic material for tubo-ovarian neoplasms resulting from therapeutic paracentesis for patients presenting with high-volume ascites. However, subtyping and immunohistochemical (IHC) characterization, which have implications in preoperative management and downstream ancillary testing, are not routinely performed in many institutions. This study aims to perform cytohistologic correlation of commonly used IHC stains to establish their reliability in peritoneal fluids/washing specimens. METHODS: A retrospective search of the laboratory information systems was performed to identify peritoneal fluid/washing specimens involved by borderline or malignant epithelial tubo-ovarian neoplasms and concurrent/subsequent surgical resection specimens. Cell blocks and tissue were stained for PAX8, WT-1, p53, p16, Napsin-A, estrogen receptor, and progesterone receptor, and staining between cytological and surgical specimens was compared. RESULTS: A total of 56 case pairs were included, with the following final diagnoses on histological examination: 37 high-grade serous carcinomas, eight clear cell carcinomas, one endometrioid adenocarcinoma, two low-grade serous carcinomas, and eight serous borderline tumors. There was perfect cytohistologic correlation for PAX8 (Lin's concordance correlation coefficient [LINCCC] = 1.00) and WT-1 (LINCCC = 1.00), substantial/good correlation for p53 (LINCCC = 0.96), p16 (LINCCC = 0.93), napsin-A (LINCCC = 0.91) and ER (LINCCC = 0.77), and moderate correlation for PR (LINCCC = 0.54). CONCLUSIONS: Immunohistochemical correlation between peritoneal fluid and surgical resection specimens for tubo-ovarian neoplasms is high. Common subtypes of tubo-ovarian carcinomas can be reliably distinguished on fluids using IHC.

A rare presentation of tuberculous adenitis mimicking metastatic breast lymphadenopathy.

Tuberculosis (TB) remains in 2022 a significant public health issue as it remains endemic in some areas of the globe, with a high prevalence in underdeveloped countries (Pujani, Khan, Hassan, Jetley, Raina, Breast Dis., 35(3): 195-198, 2015. doi:10.3233/BD-150405. PMID: 26406543). Pulmonary TB is the most common form, but TB can also have extrapulmonary manifestations like tubercular lymphadenopathy. Tuberculous lymphadenitis is the most extrapulmonary tuberculosis. It used to be called scrofula in the past coming from the Latin meaning breeding sow (Kokosali, Lloyd, Dent Update, 33(5): 306-308, 311, 2006. doi:10.12968/denu.2006.33.5.306. PMID: 16841612; Oberhelman, Watchmaker, Phillips, JAMA Dermatol, 155(5): 610, 2019. doi:10.1001/jamadermatol.2018.5651. PMID: 30942835). It is a common cause of peripheral lymphadenitis, seen mostly in the developing countries, but also reemerging among intravenous drugs users and immunocompromised population. Cervical nodes are the most commonly detected nodes in tuberculous lymphadenitis, accounting for 63% of the cases, followed by mediastinal (27%) and axillary nodes (8%) (Ahuja, Ying, Evans, King, Metreweli, Clin Radiol, 50(6): 391-395, 1995. doi:10.1016/s0009-9260(05)83136-8. PMID: 7789023). Tuberculous lymphadenitis affects predominantly the young population and children. There is also a slight female predilection. As to our knowledge, there have not been any reported cases as post-menopausal axillary tuberculous lymphadenitis, and it is the focus of this article.

Breast implant-associated EBV-positive diffuse large B-cell lymphoma: Two case reports and literature review.

Lymphomas associated with breast implants are mostly of the T-cell type. They are predominantly anaplastic lymphoma kinase-negative anaplastic large cell lymphoma (ALK-negative ALCL) characterized by CD30 positivity universally. Whilst the majority of primary breast lymphomas occurring in the absence of breast implants are of B-cell origin, there are few cases of implant-associated B-cell lymphomas reported to date in the literature, a subset of which are diffuse large B-cell lymphoma (DLBCL). Given the rarity of this entity, we describe two cases of breast implant-associated DLBCL. Both patients developed Epstein-Barr Virus (EBV)-positive large cell lymphoma of B-cell origin confined to the implant capsule with no evidence of systemic lymphoma. Considering the association with EBV, the activated B-cell phenotype and the presumed chronic inflammatory environment associated with the implant capsule, these might represent forms of DLBCL associated with chronic inflammation (DLBCL-CI) or fibrin-associated DLBCL (FA-DLBCL). Treatment included implant removal with total capsulectomy, and for one of the cases adjuvant systemic chemotherapy. Recognizing this rare type of breast implant-associated B-cell lymphoma could improve our understanding of this entity and hence develop appropriate management strategies.

Cytology of Extraneural Metastases of Nonhematolymphoid Primary Central Nervous System Tumors: Six Cases with Histopathological Correlation and Literature Update.

INTRODUCTION: Extraneural/-cranial metastases (ENM) of primary central nervous system (CNS) tumors are rare and may be diagnostically challenging. We describe the cytomorphological and pertinent clinical features of ENM in a case series assessed by fine-needle aspiration (FNA). A search of the laboratory information systems of 2 tertiary care centers in Toronto (2000-2015) was performed. Cases with direct extracranial/-spinal extension of CNS neoplasms were excluded. Microscopic slides of FNA and surgical specimens were reviewed. Demographic and clinicopathological data were retrieved. CASE PRESENTATION: Six cases were identified with the original diagnoses of glioblastoma, glioblastoma with primitive neuroectodermal tumor-like components, anaplastic ependymoma, myxopapillary ependymoma, atypical meningioma, and hemangiopericytoma. Median patient age at first diagnosis was 44 years (range 22-56). The time interval between initial diagnosis and first metastatic disease manifestation was 3 months to 19 years. All FNA diagnoses were rendered correctly. In 4 cases, immunohistochemistry was used to support the diagnosis. All cases had prior surgical intervention at the primary tumor site. In 4 cases, the ENM location was the ipsilateral parotid or buccal area. Two primary tumors in midline location developed ENM in the scapular area. DISCUSSION/CONCLUSION: ENM are a rare manifestation of a range of different primary CNS tumors and may involve the ipsilateral head and neck mimicking clinically a salivary gland neoplasm. FNA can rapidly discriminate ENM from other, potentially more indolent conditions. Awareness of the clinical history is paramount to avoid diagnostic confusion.

Cytology-based screening for anal intraepithelial neoplasia in women with a history of cervical intraepithelial neoplasia or cancer.

BACKGROUND: High-risk human papillomavirus (HPV) has been identified in the pathogenesis of anal cancer. The purpose of this study was to assess the prevalence of abnormal anal cytology and HPV in women aged ≥40 years who have a history of high-grade cervical squamous intraepithelial lesion (SIL) or cancer and to estimate the prevalence of anal intraepithelial neoplasia (AIN) using cytology as the primary screening modality. METHODS: Women who had a history of high-grade cervical SIL or cancer and were ≥40 years of age were included in this prospective study. Anal cytology with HPV-DNA testing was performed. All patients with abnormal anal cytology were referred for high-resolution anoscopy (HRA), and abnormal lesions were biopsied and treated if pathologically confirmed. Abnormal anal cytology correlated with HPV status, HRA findings, and clinical and demographic characteristics. RESULTS: A total of 317 women completed the study. Of these, 96 (30.3%) had abnormal anal cytology (high-grade SIL, 12.5%; low-grade SIL, 19.8%; atypical squamous cells, cannot exclude high-grade SIL, 6.3%; atypical squamous cells of undetermined significance, 61.5%) and 101 (31.9%) were HPV-DNA-positive. There was a significant association between abnormal cytology results and the presence of high-risk HPV. Of the 96 patients with abnormal cytology, 30 (31.3%) had biopsy-proven AIN on HRA, representing 9.5% of the total patient cohort; of these, 10 (33.3%) had low-grade AIN and 20 (66.7%) had high-grade AIN. Older age and smoking were significant risk factors for abnormal anal cytology. CONCLUSION: Women aged ≥40 years with a history of high-grade cervical SIL or cancer have a high rate of AIN. Screening for anal cancer may therefore be considered in this patient population. The optimal screening approach should be addressed in future studies.

Somatically Derived Yolk Sac Tumor of the Ovary in a Young Woman.

Ovarian carcinoma with a somatically derived yolk sac tumor component is a phenomenon known to mostly occur in postmenopausal women. Herein, we report an ovarian endometriosis-associated somatic yolk sac tumor arising in the background of a low-grade endometrioid adenocarcinoma in a young woman. A 27-yr-old woman presented with abdominal pain, subsequently recognized to be caused by a right ovarian mass undergoing torsion. Following operative management, microscopic examination of the salpingo-oophorectomy specimen showed endometriosis and a predominantly cystic ovarian neoplasm with 2 distinct phenotypic areas: (1) a yolk sac tumor component containing Schiller-Duval bodies and (2) a low-grade endometrioid carcinoma component with squamous metaplasia. Immunohistochemical evaluation showed distinct profiles in the yolk sac tumor (estrogen receptor/progesterone receptor/PAX8 negative, SALL4/Glypican 3 positive) and endometrioid (estrogen receptor/progesterone receptor/PAX8 positive, SALL4/Glypican 3 negative) components. Given these findings, the diagnosis of an endometriosis-associated endometrioid adenocarcinoma with a somatically derived yolk sac tumor was rendered. The tumor was staged as pT1c1 due to intraoperative spillage. The patient underwent chemotherapeutic treatment and after 15 mo of follow-up, she was alive with no evidence of recurrence. This example demonstrates that somatic yolk sac tumor differentiation in ovarian epithelial neoplasia can occur in young patients; awareness of this phenomenon is important as somatic and germ cell yolk sac neoplasia have different behavior and therapy.

Cytomorphologic Features of Gastric-Type Endocervical Adenocarcinoma in Liquid-Based Preparations.

OBJECTIVE: Gastric-type endocervical adenocarcinoma (GAS) is a recently described, uncommon, and aggressive tumor with distinct morphologic features and HPV-independent etiology. Data on GAS in liquid-based cytology (LBC) Papanicolaou (Pap) test preparations from a North American patient population are scant. We systematically assessed the cytomorphologic characteristics of GAS in LBC from patients in Ontario and examined if glandular cell nuclear area could represent a readily assessable feature which may aid in GAS detection. STUDY DESIGN: Pap test slides preceding the diagnosis of GAS were retrieved locally or requested from outside laboratories. A structured review of 15 cytomorphologic features was performed using the available LBC Pap test slides of GAS and a set of usual-type endocervical adenocarcinomas (UEA). Morphometry of the glandular cell nuclear area was performed, and normalized values were compared to UEA and benign endocervical cells. RESULTS: At least 1 Pap test (5 ThinPrep®, 11 SurePath®, and 1 direct smear) was available for 14 patients. Original LBC Pap test diagnoses were negative for intraepithelial lesion or malignancy (NILM) (7), adenocarcinoma/carcinoma (6), atypical glandular cells (2), and adenocarcinoma in situ (1). Review detected abnormal glandular cells in 6/7 NILM cases. Honeycomb-like sheets, nuclear enlargement, and microvesicular cytoplasm were the single most common architectural, nuclear, and cytoplasmic features, respectively. Microvesicular cytoplasm (100 vs. 17%), honeycomb-like sheets (87 vs. 8%), prominent nucleoli (93 vs. 25%), and anisonucleosis (93 vs. 50%) were most discriminatory for GAS versus UEA, respectively. Yellow mucin, intranuclear cytoplasmic pseudoinclusions, and goblet/Paneth-like cells were uncommon, but unique for GAS. Glandular cell nuclear area normalized to neutrophils was found to be significantly increased in GAS compared to benign endocervical cells. CONCLUSIONS: GAS is under-recognized and may mimic reactive endocervical cells. Awareness of the tumor type and its cytomorphology is critical for early detection. Identification of glandular cells with uniform nuclear enlargement in conjunction with any of the other cytologic features may help avoid false-negative Pap results. Neutrophils may serve as convenient size reference and visual aid.

Follow-up of Benign Thyroid Nodules-Can We Do Less?

OBJECTIVE: To determine the incidence of malignancy, follow-up ultrasound (US), and repeat fine needle aspiration (FNA) in thyroid nodules that have been previously biopsied as benign. METHODS: This is a retrospective, descriptive study of benign thyroid nodules evaluated by US between 2010-2011. We determined the frequency of follow-up ultrasounds and FNAs, mean years of follow-up, interval between follow-up US, change in nodule size, reasons for repeat FNA (rFNA), frequency of thyroidectomy, and thyroid malignancy during 5 years of follow-up. RESULTS: A total of 733 benign thyroid nodules were reviewed in 615 patients. Mean years of US follow-up was 3.47 ± 1.65 years; 275 (37.5%) had no follow-up US; 109 (14.9%) had 1 follow-up US; 93 (12.7%) had 2 follow-up US; and 256 (34.9%) had 3 or more follow-up US. Assessment of thyroid nodule size showed that 215 (28.8%) nodules decreased in size, 145 (19.4%) increased in size by less than 50%, and 91 (12.1%) increased in size by more than 50%. Of the 733 nodules, 17 nodules (2.3%) underwent thyroidectomy for which the pathology result of 9 (1.2%) showed malignancy, and 65 (8.9%) thyroid nodules underwent rFNA. When applying the 2015 recommendations for repeat FNA, 35% were done unnecessarily. CONCLUSION: In our sample of initially benign thyroid nodules, only 9 patients (1.2%) had pathology-proven malignancy after a mean follow-up of 3.5 years. Over 30% of patients had more than 3 rUSs. Decreased interval and frequency of rUS should be considered in future guidelines for thyroid management.

Retrospective Application of the 2015 American Thyroid Association Guidelines for Ultrasound Classification, Biopsy Indications, and Follow-up Imaging of Thyroid Nodules: Can Improved Reporting Decrease Testing?

INTRODUCTION: Thyroid ultrasound has been widely used to determine which nodules need further investigation. The goal of this study is to determine if using an ultrasonographic features checklist based on 2015 American Thyroid Association (ATA) guidelines can improve reporting and decrease unnecessary further testing. METHODS: In this retrospective study, ultrasonographic images of all nodules biopsied at our institution in 2014 and 2015 were reviewed by radiologists blinded to fine needle aspiration (FNA) biopsy result using a checklist. The checklist was prepared based on 2015 ATA guidelines. The ultrasonographic characteristics of thyroid nodules were compared with the result of biopsy to determine positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity for predicting malignancy. Radiologists also made an overall recommendation on need for FNA. RESULTS: A total of 425 thyroid nodule ultrasound scans were reviewed by radiologists. Biopsy results of 31 nodules were malignant and 394 were non-malignant. Malignant nodules showed higher frequency of solid composition, hypoechoechogenicity, and cervical lymph node involvement compared to benign nodules. Solid nodule composition had the highest PPV (13%) and NPV (94.7%). Extra-thyroid extension had the highest specificity (90.1%). Lesion vascularity had the highest sensitivity (83.8%), followed by hypoechogenicity (65.6%). Overall, the checklist had a positive predictive value of 9%, negative predictive value of 97.5%, sensitivity of 96.8%, and specificity of 11.14%. Radiologists determined that 10% of the nodules were very low-risk and did not require FNA. CONCLUSION: Using a checklist based on 2015 ATA guideline thyroid nodule ultrasonographic features is a sensitive tool with high NPV to predict benign thyroid nodule, thereby preventing unnecessary FNAs.

Serum-derived carcinoembryonic antigen (CEA) activates fibroblasts to induce a local re-modeling of the extracellular matrix that favors the engraftment of CEA-expressing tumor cells.

Elevated levels of the carcinoembryonic antigen (CEA; CEACAM5) in the serum of colorectal cancer (CRC) patients represent a clinical biomarker that correlates with disease recurrence. However, a mechanistic role for soluble CEA (sCEA) in tumor progression and metastasis remains to be established. In our study, we report that sCEA acts as a paracrine factor, activating human fibroblasts by signaling through both the STAT3 and AKT1-mTORC1 pathways, promoting their transition to a cancer-associated fibroblast (CaF) phenotype. sCEA-activated fibroblasts express and secrete higher levels of fibronectin, including cellular EDA+ -fibronectin (Fn-EDA) that selectively promote the implantation and adherence of CEA-expressing cancer cells. Immunohistochemical analyses of liver tissues derived from CRC patients with elevated levels of sCEA reveal that the expression of cellular Fn-EDA co-registers with CEA-expressing liver metastases. Taken together, these findings indicate a direct role for sCEA as a human fibroblast activation factor, in priming target tissues for the engraftment of CEA-expressing cancer cells, through the differentiation of tissue-resident fibroblasts, resulting in a local change in composition of the extracellular matrix.

Management of newly diagnosed high-risk and intermediate-risk follicular lymphoma with 90 Y ibritumomab tiuxetan in a phase II study.

Five-year overall survival for high-risk Follicular Lymphoma International Prognostic Index follicular lymphoma is only approximately 50% compared with 90% for low risk. To evaluate an approach to improve upon this poor outcome, we completed an exploratory phase II trial of intensified treatment for patients with intermediate and high-risk follicular lymphoma. Front-line treatment with chemo-immunotherapy consisting of rituximab, cyclophosphamide, vincristine, doxorubicin, and prednisone was followed by radio- immunotherapy with 90-Yttrium ibritumomab tiuxetan consolidation, and 2 years of rituximab maintenance. The 5-year overall survival for intermediate and high-risk patients was 88% and 83%, respectively. Of 33 enrolled patients, 3 were off study before receiving radio-immunotherapy. Three months post radio-immunotherapy, 28/33 (85%) patients had achieved complete response including 6 patients who had only a partial response to chemo-immunotherapy and converted to complete response after radio-immunotherapy. The 5-year progression-free survival for intermediate and high risk was 79% and 58%, respectively. Nine of 19 patients with molecular markers patients remain in molecular and clinical complete remission with a median follow-up of 48 months (range 3-84 months). Post radio-immunotherapy, hematologic toxicities were mostly grade 1 and 2. However, asymptomatic grade 3 or 4 thrombocytopenia and neutropenia occurred in 11%-36% and 10%-24% of patients, respectively. Myelodysplastic syndrome occurred in 1 patient 4 years post treatment. Whereas many patients had prolonged B-cell reduction and low immunoglobulin levels post treatment, previous immunities to rubella were maintained. More aggressive upfront approaches such as this may benefit higher risk follicular lymphoma, but confirmatory trials are required. http://www.clinicaltrials.gov: NCT01446562.

Intravascular large B-cell lymphoma presenting as Richter's syndrome with cerebral involvement in a patient with chronic lymphocytic leukemia.

Intravascular large B-cell lymphoma (IVLBCL) is an aggressive non-Hodgkin's lymphoma which can present with B symptoms, rash, and neurological deterioration. Up to 10% of cases of IVLBCL are associated with other hematological neoplasms, including this extremely rare presentation of IVLBCL as Richter's transformation in chronic lymphocytic leukemia.

A Challenging Diagnosis of IgG4-Related Disease When Understanding Limitations of Laboratory Testing Was Pivotal.

A 76-year-old man was incidentally found on a CT scan to have lymphadenopathy and bilateral kidney enlargement suggestive of infiltrative renal disease. He was largely asymptomatic but had bilateral salivary and lacrimal gland enlargement. A grossly elevated serum IgG (>70 g/L) with concomitant suppression of other immunoglobulins, a small IgG restriction, and a parotid biopsy revealing lymphoplasmacytic infiltrate with slight kappa light chain excess all suggested a lymphoproliferative disorder (LPD). The diagnostic workup was further confounded by a normal serum IgG4 concentration. Moreover, bone marrow and renal biopsies did not reveal evidence of LPD. Discussion with the laboratory not only clarified that the markedly increased total IgG could not be accounted for by the small IgG restriction, but also identified a discrepancy in the IgG4 measurement. Repeat analysis of a follow-up sample revealed an elevated IgG4 of 5.94 (reference interval: 0.039-0.864) g/L, which prompted a repeat parotid biopsy that showed predominant IgG4+ lymphocytic infiltrates. Despite the deluding presentations, a final diagnosis of IgG4-related disease (IgG4-RD) was made based on elevated serum IgG4 concentrations and histopathological findings. This case highlights the importance of recognizing limitations of laboratory testing and the benefit of close communications among clinical subspecialties and the laboratory.

Stratified Mucin-Producing Intraepithelial Lesion of the Cervix: Subtle Features Not to Be Missed.

OBJECTIVES: Stratified mucin-producing intraepithelial lesion (SMILE) is an uncommon premalignant lesion of the uterine cervix. A detailed examination of preinvasive SMILE cases including a comparison of the cytologic features with usual-type adenocarcinoma in situ (AIS) and human papillomavirus (HPV) genotyping was performed. STUDY DESIGN: Excisions and preceding Papanicolaou (Pap) tests were retrieved from the files of 2 tertiary care centers. Histologic review estimated the lesional SMILE proportion. Pap tests were reviewed and assessed for architectural, cellular and background features. Cobas® HPV test was performed. RESULTS: 13 cases were identified. Mean/median patient age was 35/33 years (range 23-51 years). Concurrent high-grade squamous intraepithelial lesion was found in 10/13 (77%) and AIS in 8/13 (62%) cases. In 6 cases, SMILE was dominant (≥50%) and represented in 5/6 corresponding Pap tests. Cytology interpretations differed more often in the SMILE-dominant group (p < 0.05). SMILE and AIS had overlapping features. Feathering and prominent nucleoli were absent in SMILE. HPV DNA was detected in all 12 cases tested. HPV 18 was most common (7/12). Excisions with positive/suspicious margins were reported in 5/6 SMILE-dominant versus 3/7 nondominant cases. CONCLUSION: SMILE is best considered as an AIS variant for cytologic, etiologic and management purposes. Cytologic features overlap with AIS, but are more subtle and easily missed. HPV testing may play a role in facilitating SMILE detection.