Reliably making the primary diagnosis of mesothelioma utilizing serous fluid cytology specimens: an institutional experience.

INTRODUCTION: The diagnosis of mesothelioma has historically been challenging, especially on serous fluid cytology (SFC). Distinguishing between reactive and neoplastic mesothelial cells can be difficult on cytomorphology alone. However, additional ancillary tests, such as BRCA1 associated protein-1 immunohistochemistry and fluorescence in situ hybridization for cyclin-dependent kinase inhibitor 2A deletion, can provide a sensitive and highly specific method of proving malignancy. MATERIALS AND METHODS: SFC specimens diagnosed as mesothelioma, suspicious for mesothelioma (SM), and atypical mesothelial cells (AMCs) since 2012 were identified by querying the laboratory information system. Clinical data and pathologic parameters were gathered. RESULTS: One hundred ten cases of mesothelioma, SM, and AMC were identified. Of these, 61 cases had a definitive diagnosis of mesothelioma on SFC. Average age at SFC diagnosis was 67 years (26-87 years), with most patients being male (67%). Out of the 61 cases, 11 cases (18%) had an initial diagnosis of mesothelioma made on SFC specimens, with 5 of these 11 cases being in patients that never received a histologic diagnosis of mesothelioma. Ancillary studies were utilized in all 11 cases. An initial diagnosis of metastatic mesothelioma was made on SFC in 9 cases (15%). For 6 of these 9 cases, the SFC diagnosis was the sole diagnosis of metastatic mesothelioma without a companion histologic diagnosis. In addition, 15 cases were diagnosed as SM, with 11 of these cases following a definitive mesothelioma diagnosis. Thirty-four cases were diagnosed as AMC, with 27 cases following a definitive mesothelioma diagnosis. CONCLUSIONS: The diagnosis of mesothelioma can be reliably made on SFC with the appropriate cytomorphology criteria and/or confirmatory ancillary testing.

Cytopathologic diagnosis of extragonadal germ cell tumors: A 10-year institutional review.

BACKGROUND: The occurrence of extragonadal germ cell tumors (EGGCTs), either as primary tumors or metastatic disease, is rare. Forms of cytologic sampling, including fluid analysis, fine-needle aspiration, and/or small-core needle biopsy, have been shown to be reliable methods for the diagnosis of germ cell tumors. This study aims to investigate the utility of cytopathologic techniques in the diagnosis of EGGCTs at the authors' institution. METHODS: The laboratory information system was queried over a period of 10 years (2012-2022) to identify all cytology cases diagnosed on fluid cytology, FNA, and/or small-core biopsy as germ cell tumors in extragonadal locations. Patient demographics, tumor location, serum tumor marker levels, cytopathologic diagnosis, and follow-up surgical resection data were reviewed and correlated. RESULTS: A total of 35 cases from 32 patients (all males) were identified. Thirty specimens contained satisfactory material for diagnosis (86%) and five were less than optimal for evaluation (14%). Despite this, all cases had clinically useful cytopathologic diagnoses. A total of 19 cytology cases (16 patients) had follow-up resection specimens available. Of these, 11 patients underwent preoperative chemotherapy. Nine patients showed no evidence of residual tumor and two showed histologic concordance. Of the five patients who did not have preoperative chemotherapy, all showed concordant histologic diagnoses. CONCLUSIONS: Cytology can provide a reliable, accurate method for diagnosing EGGCTs. The practice of preoperative (neoadjuvant) chemotherapy places an extreme importance on the initial cytopathologic diagnosis because the majority of patients with follow-up resection in this series showed no residual tumor.

A thyroid EIF1AX story: how clinical, cytologic, and molecular surveillance led to appropriate management.

INTRODUCTION: Indeterminate thyroid cytology diagnoses are associated with intermediate risks of malignancy. Application of molecular testing (MT) to indeterminate specimens provides additional diagnostic and prognostic information. While a positive or suspicious MT result may prompt surgery, a negative MT result is associated with a low probability of cancer or noninvasive follicular thyroid neoplasm with papillary-like nuclear features and approximates that of a benign cytology diagnosis. Furthermore, ThyroSeq v3 MT has a "currently negative" result for findings with the probability of cancer or noninvasive follicular thyroid neoplasm with papillary-like nuclear feature that is slightly greater than that for the negative ThyroSeq v3 MT result but less than 10%, suggesting active surveillance. In this report, we discuss a case of a patient for whom clinical, cytologic, and molecular surveillance led to timely surgery and management. CLINICAL DETAILS: A 53-year-old man with a thyroid isthmus nodule had a fine-needle aspiration cytology diagnosis of atypia of undetermined significance and a subsequent ThyroSeq v3 MT, which revealed an EIF1AX mutation and a "currently negative" MT result. Surveillance with additional fine-needle aspiration samples demonstrated concerning genomic alterations (fluctuating EIF1AX allelic frequency and a non-V600E BRAF mutation), culminating in the conversion to a positive MT result 3 years later. Resection revealed an encapsulated noninvasive, oncocytic solid subtype of papillary thyroid carcinoma with increased mitotic activity. CONCLUSION: The case is notable for clinical, cytologic, and molecular surveillance demonstrating sequential pathologic alterations in an indeterminate thyroid nodule with EIF1AX mutation, leading to timely resection of the neoplasm before invasion manifested.

Accuracy of definitive rapid onsite evaluation cytopathology diagnoses: Assessment of potentially critical diagnoses as a quality assurance measure.

INTRODUCTION: Intraprocedural rapid onsite evaluation (ROSE) of cytology specimens enhances cytopathology practice. More recently, ROSE diagnoses, like frozen section (FS) diagnoses, have guided immediate clinical decisions. In this study, we evaluated the diagnostic accuracy of definitive ROSE diagnoses in our quality assurance system over a 52-month period. MATERIALS AND METHODS: Cytopathology cases with ROSE from January 2017 to April 2021were retrieved from our laboratory information system. After excluding cases that were deferred or nondiagnostic/unsatisfactory, each definitive ROSE diagnosis (ie, negative for malignant cells or positive for malignant cells) was categorized as having agreement or disagreement with the final diagnosis. For comparison, concordance of FS diagnoses from the same time period were tabulated and compared to those of ROSE diagnoses by using χ2 testing with P < 0.05 considered statistically significant. RESULTS: Of the 1649 ROSE diagnoses, there were 15 disagreements (0.9%) with 1 final moderate interpretive disagreement (0.06%). By comparison, of the 17,469 FS diagnoses, there were 141 disagreements (0.8%) with 49 final moderate or major interpretive disagreements (0.3%). The remaining disagreements were minor. There were no statistically significant differences in the rates of final moderate and major interpretive disagreements. CONCLUSIONS: The final interpretive disagreement rates for definitive ROSE and FS diagnoses were similar in this study. Given the expanding role of ROSE and its use for immediate clinical decisions in some cases, monitoring the accuracy of definitive diagnoses may serve as an initial quality assurance measure.