Role of frozen section in intraoperative assessment of ovarian masses: a tertiary oncology center experience

Intraoperative frozen section evaluation of ovarian sex cord-stromal tumours and their mimics: a study of 121 cases with emphasis on potential diagnostic pitfalls

Ovarian sex cord-stromal tumours (SCSTs) present diagnostic difficulties during frozen section (FS) consultations due to their diverse morphology. This study aimed to evaluate the accuracy of FS evaluation of SCSTs in our institution, as well as to examine the reasons leading to incorrect FS diagnosis. Cases mimicking SCSTs and diagnosed as such during FS were also highlighted. We analysed 121 ovarian SCST cases and their mimics which underwent FS consultations over a 10-year period, to evaluate FS accuracy, reasons for deferrals and discrepancies. FS diagnoses were concordant, deferred and discrepant compared to the final diagnosis in 50 (41.3%), 39 (32.2%) and 32 (26.5%) cases, respectively. Major discrepancies (9/121, 7.4%) were mostly related to the diagnosis of adult granulosa cell tumour (AGCT). A fibromatous AGCT was misinterpreted as fibroma on FS, while a cystic AGCT was called a benign cyst. Conversely, a mesonephric-like adenocarcinoma, a sertoliform endometrioid carcinoma and a thecoma were misinterpreted as AGCT on FS. Another discrepant case was a Krukenberg tumour with prominent fibromatous stroma in which malignant signet ring cells were overlooked and misinterpreted as fibroma. Minor discrepancies were primarily associated with fibroma (21/23, 91.3%), wherein minor but potentially impactful details such as cellular fibroma and mitotically active cellular fibroma were missed due to sampling issues and misinterpretation as leiomyoma. FS evaluation for ovarian SCSTs demonstrated an overall accuracy of 78.5%, 81.0% and 81.8% for benign, uncertain/low malignant potential and malignant categories, respectively. There was no FS-related adverse clinical impact in all cases with available follow-up information (120/121 cases). Intraoperative FS evaluation of ovarian SCSTs is challenging. A small number of cases were misinterpreted, with AGCTs being the primary group where errors occur. Awareness of common diagnostic pitfalls and difficulties, alongside application of a stepwise approach, including (1) obtaining comprehensive clinical information, (2) thorough macroscopic examination and directed sampling, (3) meticulous microscopic examination with consideration of pitfalls and mimics, (4) effective communication with surgeons in difficult cases, and (5) consultation of subspecialty colleagues in challenging cases, will enhance pathologists' reporting accuracy and management of such cases in the future.

Ovarian Fibroma Presents As Uterine Leiomyoma in a 61-Year-Old Female: A Case Study

Uterine leiomyoma should be considered when a female patient reports symptoms of abdominal pressure and abnormal vaginal bleeding. However, the symptoms of a uterine leiomyoma are vast and overlap with other possible diseases that are difficult to distinguish even with imaging studies. This is why it is important for physicians and healthcare providers to keep an open mind and have a broad differential diagnosis.  In this case study, we present a 61-year-old postmenopausal female patient who presented to the emergency department with complaints of pelvic and abdominal pain, as well as vomiting and diarrhea. She was admitted for observation. A complete blood count (CBC), comprehensive metabolic panel (CMP), and urinalysis revealed no abnormalities; a pelvic ultrasound and CT scan reported possible adnexal torsion. The patient remained stable and the pain had subsided when she was seen the next morning by her gynecologist (GYN) who discharged her to follow-up in the office. Subsequent examinations that aided in the diagnosis included, but were not limited to pelvic and transvaginal ultrasounds, an abdominal and pelvic CT, and a pelvic MRI. In this case, the MRI revealed an 11-cm mass that could represent a torsioned pedunculated necrotic fibroid originating from the uterus. Radiology recommended surgical removal. Upon removal and review of the pathology of the mass, it was revealed to be a torsioned, partially necrotic fibroma that had originated from the ovary and not from the uterus, as imaging had originally suggested.

A Quantitative and Qualitative Assessment of Frozen Section Diagnosis Accuracy and Deferral Rate Across Organ Systems

OBJECTIVES

Monitoring of frozen section diagnostic performance provides an important quality improvement measure.

METHODS

Surgical specimens involving a frozen section diagnosis over a 3-year period were retrospectively reviewed. Glass slides were reviewed on cases with discordance. Discordance and deferral rates were calculated.

RESULTS

Of 3,675 frozen section diagnoses included, 96 (2.7%) were discordant with the final diagnosis. Additionally, 114 frozen section diagnoses (3.1%) were deferred. The organ-specific discordance rates were lowest in breast and genitourinary specimens and highest for pancreas, lymph node, and gynecologic specimens. Deferral rates were highest in musculoskeletal, breast, and hepatobiliary cases and lowest in thyroid, parathyroid, and neuropathology cases. Discordance was explained by block-sampling error (45%), specimen-sampling error (27%), or interpretation error (27%). Discordant frozen section diagnoses from gynecologic specimens were responsible for 81% of specimen-sampling errors; frozen section diagnoses of lymph nodes, head and neck, and pancreas were responsible for 54% of interpretation errors; 51% of block-sampling errors involved lymph node evaluation for metastatic carcinoma.

CONCLUSIONS

Careful gross evaluation and microscopic examination of multiple levels should minimize specimen-sampling error and block-sampling error, respectively. Periodic review of accuracy and deferral rates may help reduce errors and improve the overall performance of this essential procedure.

Comparison of Frozen and Permanent Section Diagnosis in Ovarian Neoplasms: Analysis of Factors Affecting Accuracy

Ovarian cancer is the seventh most common form of cancer among women worldwide. The aim of the study was to determine the accuracy of a frozen section and the factors affecting the accuracy of frozen diagnosis of ovarian neoplasms. This retrospective, cross-sectional study was conducted on 401 patients with ovarian masses with frozen section diagnosis in Shahid Faghihi Hospital affiliated to Shiraz University of Medical Sciences between 2014 and 2018. Each ovarian tumor sample was evaluated for histopathologic diagnosis using frozen and paraffin-embedded sections, which were reviewed by an expert gynecologic pathologist. Accuracy and diagnostic values were estimated by comparing the results of the 2 techniques, using the paraffin section as the gold standard. The overall accuracy of the frozen section was 94.5%. Its sensitivity was 85.3% for malignant, 88.2% for borderline, and 99.6% for benign tumors. Its specificity was also 99.7% for malignant, 98.0% for borderline, and 90.9% for benign tumors. The positive predictive value was 98.9% for malignant, 86.5% for borderline, and 94.6% for benign tumors. Most false negatives occurred in mucinous and borderline tumors. The sensitivity of malignant tumors of germ cell and sex cord-stromal cell types were 64.3% and 95.5%, respectively. The specificity of germ cell and sex-cord stromal tumors were 100% and 93.8%, respectively. Frozen section seems to be a precise technique for histopathologic diagnosis of ovarian tumors. However, borderline and mucinous tumors are the most problematic issues during frozen section diagnosis and malignant germ cell tumors have the lowest sensitivity.

Accuracy and Reproducibility of Frozen Section Diagnosis in Ovarian Tumors: A 10-Year Experience at a Tertiary Cancer Center

CONTEXT.—

Intraoperative consultation-frozen section diagnosis (FSD)-determines tumor pathology and guides the optimal surgical management of ovarian neoplasms intraoperatively.

OBJECTIVE.—

To evaluate the diagnostic accuracy of the FSD and analyze the discrepancy between the FSD and final diagnosis.

DESIGN.—

This is a retrospective study of 618 ovarian neoplasm FSDs from 2009 to 2018 at a tertiary health care center. The discrepant cases were reviewed and reevaluated by gynecologic and general surgical pathologists. The outcomes of interest were performing unnecessary procedure, returning for a second surgery, and 30-day postoperative mortality.

RESULTS.—

The sensitivity and the positive predictive value of the FSD were lower in borderline tumors than in benign and malignant epithelial ovarian tumors. Major and minor discrepancies were identified in 5.3% (33 of 618) and 12.3% of (76 of 618) cases, respectively. A root cause analysis of the major discrepant cases showed that sampling error accounted for 43% (14 of 33). The discrepancy distributions of gynecologic and general surgical pathologists were statistically similar in the overall cohort (P = .65). The overall κ for diagnostic agreement among gynecologic pathologists, general surgical pathologists, and final diagnosis was 0.18 (0.10-0.26, P < .001), implying only a slight overall agreement. Of the major discrepant cases, only 3 had a clinical implication. One overdiagnosed patient underwent unnecessary procedure and 2 underdiagnosed patients were recommended to return for a second surgery. No patient had 30-day postoperative mortality.

CONCLUSIONS.—

Frozen section diagnosis remains a definitive diagnostic tool in ovarian neoplasms and plays a crucial role in guiding intraoperative surgical management.

The usefulness of intraoperative consultation for the diagnosis of borderline ovarian tumors

Background

Borderline ovarian tumors (BTs) must be recognized during the surgery by intraoperative consultation (IOC) to guide surgical treatment; however, this diagnosis can be imprecise. Therefore, this study aimed to evaluate the diagnostic accuracy of IOC for the diagnosis of BT.

Methods

A retrospective cohort study was carried out including all women diagnosed with a pelvic tumor consecutively surgically treated from 2005 to 2015 with IOC. We calculated the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and likelihood ratios (LR) for the IOC and BTs.

Results

A total of 758 patients were enrolled, the median age was 44 years, the median tumor size was 11.8 cm, and the median CA-125 levels were 45.65 U/µL. After IOC, 458 (64.1%) cases were diagnosed as benign, 111 (14.7%) as BT, and 161 (21.2%) as malignant. The definitive diagnosis was a benign tumor in 448 (59.1%) cases, BT in 110 (14.5%), and 200 (26.4%) cases were malignant. The diagnostic accuracy of the IOC for BT diagnosis was 89.8% (sensitivity =65.5%, specificity =93.9%). The diagnosis performance of IOC for the diagnosis between BT and benign tumors (n=546) had a sensitivity of 69.9%, a specificity of 98.4%, and a diagnostic accuracy of 84%; meanwhile for the diagnosis between BT and malignant tumors (n=242) IOC had a sensitivity of 92.3%, a specificity of 81.7%, and a diagnostic accuracy of 87%.

Conclusions

For practitioners, knowing the accuracy and limitations of the IOC for BT enables the better selection of cases to perform a complete staging surgery.

Role of Frozen Section in Surgical Management of Ovarian Neoplasm

Objective:

Cancers of the adnexae, including ovarian and fallopian tube, constitute the eighth most common cancers among women worldwide. Surgery remains the cornerstone in the management of ovarian cancer. Intraoperative frozen section diagnosis of ovarian tumors is widely used in making this distinction and to decide the course of surgery. Therefore, the accuracy of this technique is very important. The aim was to determine the overall accuracy, sensitivity, specificity, and predictive values of frozen section for ovarian tumors and to evaluate the role of frozen section in the surgical management of ovarian tumors.

Materials and Methods:

This was a descriptive longitudinal study conducted in the gynecology department of a tertiary care hospital. During the 1 ½ year period of data collection, frozen section was performed among 60 cases of ovarian neoplasms. The overall accuracy, sensitivity, specificity and predictive values of frozen section for benign, borderline and malignant categories of ovarian tumors were studied.

Results:

Out of the 60 patients of ovarian tumors, frozen section diagnosis showed that 43 (71.7%) tumors were benign, 11 (18.3%) were malignant and 6 (10%) were of borderline nature. Final histopathological diagnosis showed that 45 (75%) tumors were benign, 11 (18.3%) were malignant and 4 (6.7%) were borderline. Frozen section for benign tumors had 95% sensitivity, 100% specificity, 100% positive predictive value (PPV) and 88% negative predictive value (NPV). Malignant tumors had 90% sensitivity, 97% specificity, 90% PPV and 97% NPV with frozen section. However, frozen section had low sensitivity (75%) and PPV (50%) for borderline tumors. Specificity was 94% and NPV 98% in this group of tumors.

Conclusion:

Frozen section was found to be an accurate and useful modality in the intraoperative evaluation of patients with ovarian neoplasm. The results can help to decide the type and extent of surgery.

Diagnostic accuracy of frozen section analysis of borderline ovarian tumors: a meta-analysis with emphasis on misdiagnosis factors

Objective: First, to evaluate the sensitivity and positive predictive value (PPV) of intra-operative frozen section (FS) diagnosis in borderline ovarian tumors (BOTs), and to explore the factors affecting the diagnostic accuracy. Second, to assess the clinical outcomes of misdiagnosed BOT patients.

Methods: We performed a retrospective study of all patients diagnosed as BOT through FS or paraffin section (PS) at Qilu Hospital between January 2005 and December 2015. Clinical and pathologic data were extracted. Univariate analysis was performed using standard two-sided statistical tests. We also performed a meta-analysis to further validate the findings.

Results: In our retrospective study, 155 patients were included. Agreement between FS and PS diagnosis was observed in 127/155 (81.9%) patients, yielding a sensitivity of 92.7% and a PPV of 87.6%. Under-diagnosis and over-diagnosis occurred in 22 cases (14.2%) and 6 cases (3.9%), respectively. In our univariate analysis of our retrospective study, tumor size (p=0.048) and surgery approach (p=0.024) were significantly associated with misdiagnosis.

The pooled analysis of 13 studies including 1,577 patients indicated that the accuracy (69.2%), sensitivity (82.5%), and PPV (81.1%) were low; also under-diagnosis (20.2%) and over-diagnosis (10.5%) were frequent. The meta-analysis results showed that mucinous histology (p < 0.0001, OR=2.03 [1.47-2.81]) and unilateral tumors (p=0.001, OR=2.39 [1.41-4.06]) were associated with the misdiagnosis of BOT. In our retrospective study, there was no statistical significance of clinical outcome such as extent of surgery (p=0.838), recurrence (p=0.586), fertility (p=0.560), death (p=0.362) between misdiagnosed and accurately diagnosed BOT patients.

Conclusions: FS analysis of BOTs has low accuracy, sensitivity, and PPV. Under-diagnosis and over-diagnosis are frequent. Meta-analysis results verify that mucinous histology and unilateral tumors are associated with misdiagnosis of FS. Nevertheless, misdiagnosed patients have a good clinical outcome despite the high frequency of misdiagnosis through FS.

Accuracy of intraoperative frozen section for the evaluation of ovarian neoplasms: an institutional experience

Background

Ovarian neoplasms are a heterogeneous group of tumors including surface epithelial, germ cell and sex cord stromal tumors with a subset having low malignant potential (borderline tumors). While the surgical management plan differs in different categories of tumors, preoperative diagnosis is seldom available. In these circumstances, the role of frozen section becomes invaluable. In the current study, we aimed to evaluate the accuracy of the frozen section of ovarian tumors in our setup.

Methods

It was a retrospective study involving 141 cases of ovarian tumors undergoing surgical resection with frozen section evaluation from January 2009 to December 2014. After gross examination, one to five blocks were prepared on the frozen section depending upon the size of the specimen. After frozen section reporting, specimens were processed routinely for final paraffin section evaluation. Results of frozen and paraffin sections were categorized in benign, borderline, and malignant, and accuracy of frozen section was determined.

Results

Out of 141 cases, 107 were diagnosed as benign on final (paraffin) examination, while 6 were borderline and 28 were malignant. Out of 107 benign cases, 45 were non-neoplastic cystic lesions of the ovary including endometriotic, follicular, and corpus luteal cysts. The most common benign neoplastic tumor was mature cystic teratoma (20 cases) followed by mucinous cystadenoma (19 cases), serous cystadenoma (14 cases), sex cord stromal tumors (8 cases), and Brenner tumor (1 case). Among borderline cases, four cases were serous and two of mucinous neoplasms. The most common malignant neoplasm was serous carcinoma (11 cases) followed by mucinous carcinoma (6 cases). The overall accuracy of frozen section diagnosis is above 99 %. The sensitivity and specificity for benign tumors were found to be 100 and 97 %, respectively. The sensitivity and specificity for borderline tumors was 83 and 99 %, respectively, while for malignant tumors, it was 96 and 100 %, respectively.

Conclusions

We found a high sensitivity and specificity of frozen section for the diagnosis of ovarian tumors and to determine its malignant potential. Therefore, it should always be used when the preoperative diagnosis is not definite to govern extent of surgical resection. However, under-diagnosis can occur in tumors of borderline category which can be minimized by increased sampling on the frozen section.

Intraoperative frozen section analysis for the diagnosis of early stage ovarian cancer in suspicious pelvic masses

BACKGROUND

Women with suspected early-stage ovarian cancer need surgical staging which involves taking samples from areas within the abdominal cavity and retroperitoneal lymph nodes in order to inform further treatment. One potential strategy is to surgically stage all women with suspicious ovarian masses, without any histological information during surgery. This avoids incomplete staging, but puts more women at risk of potential surgical over-treatment.A second strategy is to perform a two-stage procedure to remove the pelvic mass and subject it to paraffin sectioning, which involves formal tissue fixing with formalin and paraffin embedding, prior to ultrathin sectioning and multiple site sampling of the tumour. Surgeons may then base further surgical staging on this histology, reducing the rate of over-treatment, but conferring additional surgical and anaesthetic morbidity.A third strategy is to perform a rapid histological analysis on the ovarian mass during surgery, known as 'frozen section'. Tissues are snap frozen to allow fine tissue sections to be cut and basic histochemical staining to be performed. Surgeons can perform or avoid the full surgical staging procedure depending on the results. However, this is a relatively crude test compared to paraffin sections, which take many hours to perform. With frozen section there is therefore a risk of misdiagnosing malignancy and understaging women subsequently found to have a presumed early-stage malignancy (false negative), or overstaging women without a malignancy (false positive). Therefore it is important to evaluate the accuracy and usefulness of adding frozen section to the clinical decision-making process.

OBJECTIVES

To assess the diagnostic test accuracy of frozen section (index test) to diagnose histopathological ovarian cancer in women with suspicious pelvic masses as verified by paraffin section (reference standard).

SEARCH METHODS

We searched MEDLINE (January 1946 to January 2015), EMBASE (January 1980 to January 2015) and relevant Cochrane registers.

SELECTION CRITERIA

Studies that used frozen section for intraoperative diagnosis of ovarian masses suspicious of malignancy, provided there was sufficient data to construct 2 x 2 tables. We excluded articles without an available English translation.

DATA COLLECTION AND ANALYSIS

Authors independently assessed the methodological quality of included studies using the Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS-2) domains: patient selection, index test, reference standard, flow and timing. Data extraction converted 3 x 3 tables of per patient results presented in articles into 2 x 2 tables, for two index test thresholds.

MAIN RESULTS

All studies were retrospective, and the majority reported consecutive sampling of cases. Sensitivity and specificity results were available from 38 studies involving 11,181 participants (3200 with invasive cancer, 1055 with borderline tumours and 6926 with benign tumours, determined by paraffin section as the reference standard). The median prevalence of malignancy was 29% (interquartile range (IQR) 23% to 36%, range 11% to 63%). We assessed test performance using two thresholds for the frozen section test. Firstly, we used a test threshold for frozen sections, defining positive test results as invasive cancer and negative test results as borderline and benign tumours. The average sensitivity was 90.0% (95% confidence interval (CI) 87.6% to 92.0%; with most studies typically reporting range of 71% to 100%), and average specificity was 99.5% (95% CI 99.2% to 99.7%; range 96% to 100%).Similarly, we analysed sensitivity and specificity using a second threshold for frozen section, where both invasive cancer and borderline tumours were considered test positive and benign cases were classified as negative. Average sensitivity was 96.5% (95% CI 95.5% to 97.3%; typical range 83% to 100%), and average specificity was 89.5% (95% CI 86.6% to 91.9%; typical range 58% to 99%).Results were available from the same 38 studies, including the subset of 3953 participants with a frozen section result of either borderline or invasive cancer, based on final diagnosis of malignancy. Studies with small numbers of disease-negative cases (borderline cases) had more variation in estimates of specificity. Average sensitivity was 94.0% (95% CI 92.0% to 95.5%; range 73% to 100%), and average specificity was 95.8% (95% CI 92.4% to 97.8%; typical range 81% to 100%).Our additional analyses showed that, if the frozen section showed a benign or invasive cancer, the final diagnosis would remain the same in, on average, 94% and 99% of cases, respectively.In cases where the frozen section diagnosis was a borderline tumour, on average 21% of the final diagnoses would turn out to be invasive cancer.In three studies, the same pathologist interpreted the index and reference standard tests, potentially causing bias. No studies reported blinding pathologists to index test results when reporting paraffin sections.In heterogeneity analyses, there were no statistically significant differences between studies with pathologists of different levels of expertise.

AUTHORS' CONCLUSIONS

In a hypothetical population of 1000 patients (290 with cancer and 80 with a borderline tumour), if a frozen section positive test result for invasive cancer alone was used to diagnose cancer, on average 261 women would have a correct diagnosis of a cancer, and 706 women would be correctly diagnosed without a cancer. However, 4 women would be incorrectly diagnosed with a cancer (false positive), and 29 with a cancer would be missed (false negative).If a frozen section result of either an invasive cancer or a borderline tumour was used as a positive test to diagnose cancer, on average 280 women would be correctly diagnosed with a cancer and 635 would be correctly diagnosed without. However, 75 women would be incorrectly diagnosed with a cancer and 10 women with a cancer would be missed.The largest discordance is within the reporting of frozen section borderline tumours. Investigation into factors leading to discordance within centres and standardisation of criteria for reporting borderline tumours may help improve accuracy. Some centres may choose to perform surgical staging in women with frozen section diagnosis of a borderline ovarian tumour to reduce the number of false positives. In their interpretation of this review, readers should evaluate results from studies most typical of their population of patients.