Cytology of Benign Peritoneal Fluids and Pelvic Washing Specimens: Diagnostic Cytomorphologic Features and Pitfalls.

BACKGROUND: Pelvic washing and peritoneal fluid cytology specimens are used to detect peritoneal spread of malignancies. In most cases, identification of malignancy in these specimens is straightforward, but benign processes may occasionally mimic neoplasia and cause diagnostic difficulty. SUMMARY: In this article, we perform a focused review of common benign entities encountered in pelvic washing and peritoneal fluid specimens during routine practice which may cause difficulty and discuss helpful features for avoiding diagnostic pitfalls. KEY MESSAGES: Application of strict cytomorphologic criteria, along with judicious use of ancillary studies and correlation with clinical, intraoperative, radiologic, and other pathologic findings, can help resolve most problematic cases.

Role of Ancillary Techniques in Fluid Cytology.

The cytologic evaluation of serous effusions may be challenging for a number of reasons. Distinction of benign, reactive conditions from malignancy represents the main focus when examining these specimens. The morphologic diagnosis of malignancy may be difficult due to the relative paucity of abnormal cells. In other situations, cellularity is not an issue, but the ability to confidently identify a second, foreign (i.e., tumor) population within a background mesothelial cells on the basis of cytomorphologic features alone may pose problems. Cases with definitive morphologic evidence of malignancy may require additional studies in order to determine the tumor subtype and, in the case of carcinoma, the primary site of origin. Cases in which a definitive and precise diagnosis of malignancy is made may be optimal candidates for further molecular testing in order to gain prognostic information and guide personal therapeutic decisions. Finally, while an inflammatory or infectious condition can be suggested on the basis of cellular components and associated background elements, the identification of causative agent(s) may be difficult without additional studies. In all of these situations, the use of ancillary studies and techniques is critical; their utility and appropriate application are the subject of this review.

Measurement and immunophenotyping of pleural fluid EpCAM-positive cells and clusters for the management of non-small cell lung cancer patients.

OBJECTIVES: A malignant pleural effusion (MPE) is a common complication in non-small cell lung cancer (NSCLC) with important staging and prognostic information. Patients with MPEs are often candidates for advanced therapies, however, the current gold standard, cytological analysis of pleural fluid samples, has limited sensitivity. We aimed to demonstrate the feasibility of non-invasive enumeration and immunophenotyping of EpCAM-positive cells in pleural fluid samples for the diagnosis of a MPE in NSCLC patients. MATERIALS AND METHODS: Pleural fluid specimens were prospectively collected from patients with NSCLC and the CellSearch® technology was utilized for the enumeration of pleural EpCAM-positive cells (PECs) and determination of PD-L1 expression on PECs from pleural fluid samples. The diagnostic performance of the enumeration of single PECs and PEC clusters was assessed using receiver operating characteristic (ROC) curves. The Kaplan-Meier method and Cox proportional hazards model was used to assess the impact of PECs and PEC clusters on overall survival (OS). RESULTS: 101 NSCLC patients were enrolled. The median number of PECs was significantly greater in the malignant (n = 84) versus non-malignant group (n = 17) (730 PECs/mL vs 1.0 PEC/mL, p < 0.001). The area under the ROC curve was 0.91. A cutoff value of 105 PECs/mL had a sensitivity and specificity of 73% and 100% for the diagnosis of a MPE, respectively. Among 69 patients with a pathology-confirmed MPE and tissue immunohistochemistry (IHC) results, 15 (22%) had greater than 50% PD-L1+ PECs. Overall concordance between tissue and PEC PD-L1 expression was 76%. Higher numbers of pleural effusion single PECs were associated with inferior overall survival (Cox adjusted HR 1.8, 95% CI: 1.02-3.05 p = 0.043). CONCLUSION: Non-invasive measurement of PECs in NSCLC patients, using an automated, clinically available approach, may improve the diagnostic accuracy of a MPE, allow for immunophenotyping of PECs, and provide prognostic information.

Diagnostic utility of fine-needle aspiration cytology of lesions involving bone.

BACKGROUND: Fine-needle aspiration (FNA) is utilized in the diagnostic work-up of bone lesions in a number of institutions, either in isolation or in conjunction with core biopsy. We report our experience with FNA of bone-based lesions, including comparison of this approach with concurrent core biopsy specimens. METHODS: Retrospective review over a 5-year period (2011-2015) revealed 233 cases of bone FNAs. RESULTS: The most commonly encountered diagnosis was malignant neoplasm (160 cases, 68.7%); within this group of malignancies, 103 cases (64.4%) represented metastatic carcinoma. Benign lesions were encountered infrequently (9 cases, 3.9%). While 37 cases (15.9%) revealed "no evidence of malignancy," 12 cases (5.2%) showed atypical findings, 3 cases (1.3%) demonstrated inflammatory conditions, and 12 aspiration biopsies were deemed nondiagnostic (5.2%). In 202 cases, concurrent core biopsies were performed following FNA and rapid on-site evaluation (ROSE). Comparison of the FNA and core biopsy diagnoses among malignant neoplasms revealed 19 diagnostic discrepancies, including 16 cases with a false-negative FNA (7.9% of all FNAs with concurrent core biopsy) and 3 cases with a false-negative core biopsy (1.5% of all cases with corresponding FNA). CONCLUSION: Our findings indicate that FNA of bone lesions is a useful diagnostic technique with high sensitivity, particularly when the cytologic findings are interpreted in conjunction with the core biopsy and pertinent clinical and radiologic findings. In addition, ROSE followed by open, dynamic communication with the performing radiologist leads to an extremely low rate of inadequate core biopsy specimens, resulting in optimal patient diagnosis and management. Diagn. Cytopathol. 2017;45:608-613. © 2017 Wiley Periodicals, Inc.

Fine-needle aspiration cytology of endometriosis.

Endometriosis commonly involves the pelvis, but may also present as a palpable mass in extrapelvic sites, such as the abdominal wall or inguinal region, where it can be evaluated by fine needle aspiration (FNA). In this report, we illustrate the findings seen in seven cases of endometriosis diagnosed by FNA in patients with a chief complaint of pain associated with an abdominal wall or pelvic mass, occurring in a setting of prior pelvic surgery. The most common previous surgery was Cesarean section (n = 6), followed by hysterectomy (n = 2), and hernia repair (n = 1). In all cases, cytologic examination revealed a glandular component composed largely of orderly fragments of cohesive epithelial cells, a spindle cell stromal component presenting either as loosely organized tissue fragments or single cells, and rare hemosiderin-laden macrophages. Four cases showed focal cytologic atypia in the glandular component with extreme nuclear atypia identified in two of these cases. Atypical features included nuclear crowding and disorganization, nuclear enlargement, hyperchromasia with irregular chromatin distribution and anisonucleosis, raising the possibility of a coexistent malignancy and recommendation for excision. Although malignancy was not identified in follow-up surgical excision specimens, the wide range of cytomorphologic changes that can be seen in FNA specimens of endometriosis should be recognized. Diagn. Cytopathol. 2017;45:359-363. © 2016 Wiley Periodicals, Inc.

Pleural effusion, pneumothorax, and lung entrapment in rheumatoid arthritis.

Rheumatoid arthritis (RA)-associated pleural effusions are usually small and asymptomatic with no need for intervention, but complex and symptomatic rheumatoid pleural effusions may be seen and are associated with significant morbidity and mortality. Pleural effusions may develop before, concurrently with, or after the joint manifestations of RA. The classic features of RA-associated pleural effusions include high cell counts and protein, lipid, and lactate dehydrogenase levels and very low glucose levels, along with distinctive cytopathologic findings: slender spindle-shaped cells, multinucleated giant cells, eosinophilic granular debris, and the absence of mesothelial cells. Rarely, rheumatoid pleural involvement can include pneumothorax or can be severe enough to progress to lung entrapment, which may cause significant restrictive lung disease and require surgical therapy. Rheumatoid pleural involvement may not always correlate with joint activity but can be a significant cause of shortness of breath for patients with RA.

Fine-needle aspiration of superficial myxoid neurofibroma in the region of the breast.

Myxoid neurofibromas are benign spindle cell tumors of perineural cell origin with a broad pathologic differential diagnosis, which includes myxoma, myxoid liposarcoma, myxoid dermatofibrosarcoma protuberans, and low-grade fibromyxoid sarcoma. We present an unusual case of superficial myxoid neurofibroma in the region of the breast that underwent pre-operative fine-needle aspiration (FNA). The differential diagnosis for a myxoid subcutaneous lesion should include myxoid neurofibroma when myxoid material is encountered in an otherwise hypocellular FNA.

Use of flow cytometry in the diagnosis of lymphoproliferative disorders in fluid specimens.

The diagnostic evaluation of fluid specimens, including serous effusions and cerebrospinal fluids (CSFs), can be challenging for a number of reasons. The evaluation of lymphoid proliferations in these specimens can be particularly problematic, given the frequent presence of coexisting inflammatory conditions and the manner in which these specimens are processed. As a result, immunophenotypic analysis of hematopoietic cell populations by flow cytometry has emerged as a useful ancillary study in the diagnosis of these specimens, both in patients with and without a previous history of a lymphoproliferative disorder. In this study, we review our experience with flow cytometry in fluid specimens over a four-year period. Flow cytometry was performed in 184 of 6,925 total cases (2.7% of all fluids). Flow cytometry was performed in 4.8% of pleural fluids (positive findings in 38%, negative in 40%, and atypical in 18%), 1.1% of peritoneal fluids (positive in 40%, negative in 50%, and atypical in 10%), 1.9% of pericardial fluids (positive in 67%, negative in 33%), and 1.9% of CSFs (positive in 23%, negative in 55%, atypical in 3%). The specimen submitted was inadequate for analysis in 9.2% of cases, most commonly with CSF specimens, but was not related to the volume of fluid submitted. Atypical flow cytometry findings and atypical morphologic findings in the context of negative flow cytometry results led to the definitive diagnosis of a lymphoproliferative disorder in a significant number of cases when repeat procedures and ancillary studies were performed.

Functional profiling of live melanoma samples using a novel automated platform.

AIMS: This proof-of-concept study was designed to determine if functional, pharmacodynamic profiles relevant to targeted therapy could be derived from live human melanoma samples using a novel automated platform. METHODS: A series of 13 melanoma cell lines was briefly exposed to a BRAF inhibitor (PLX-4720) on a platform employing automated fluidics for sample processing. Levels of the phosphoprotein p-ERK in the mitogen-activated protein kinase (MAPK) pathway from treated and untreated sample aliquots were determined using a bead-based immunoassay. Comparison of these levels provided a determination of the pharmacodynamic effect of the drug on the MAPK pathway. A similar ex vivo analysis was performed on fine needle aspiration (FNA) biopsy samples from four murine xenograft models of metastatic melanoma, as well as 12 FNA samples from patients with metastatic melanoma. RESULTS: Melanoma cell lines with known sensitivity to BRAF inhibitors displayed marked suppression of the MAPK pathway in this system, while most BRAF inhibitor-resistant cell lines showed intact MAPK pathway activity despite exposure to a BRAF inhibitor (PLX-4720). FNA samples from melanoma xenografts showed comparable ex vivo MAPK activity as their respective cell lines in this system. FNA samples from patients with metastatic melanoma successfully yielded three categories of functional profiles including: MAPK pathway suppression; MAPK pathway reactivation; MAPK pathway stimulation. These profiles correlated with the anticipated MAPK activity, based on the known BRAF mutation status, as well as observed clinical responses to BRAF inhibitor therapy. CONCLUSION: Pharmacodynamic information regarding the ex vivo effect of BRAF inhibitors on the MAPK pathway in live human melanoma samples can be reproducibly determined using a novel automated platform. Such information may be useful in preclinical and clinical drug development, as well as predicting response to targeted therapy in individual patients.

Goals and guidelines for residency training in cytopathology.

The time available to train residents in cytopathology has been impacted by the contraction of the training period, in the face of growing expectations for training in other facets of anatomic pathology and laboratory medicine (i.e. molecular genetic pathology, laboratory management and administration). Guidelines for appropriate levels of achievement in cytopathology have been proposed by those within the field, under the guidance of the Accreditation Council for Graduate Medical Education (ACGME). Presented here is a discussion of recommendations for training programs, in order to effectively train residents to an acceptable level of competence in cytopathology, within the training time allotted.

Utility of CD138 (syndecan-1) in distinguishing carcinomas from mesotheliomas.

CD138 (Syndecan-1) is a transmembrane heparan sulfate proteoglycan present on the surface of plasma cells and epithelial cells. CD138 is also expressed in some hematopoietic neoplasms and has recently been observed in carcinomas. We characterized CD138 expression in cell-block preparations of fluids/effusions, focusing on the distinction between carcinoma and mesothelioma. One hundred formalin-fixed, paraffin-embedded cell-block sections of fluids/effusions consisting of 58 metastatic carcinomas, 24 mesotheliomas, 11 reactive mesothelial cell proliferations, 3 lymphomas, 3 metastatic sarcomas, and 1 metastatic melanoma were stained with a monoclonal antibody against CD138. CD138 staining was observed in 32/58 (55%) metastatic carcinomas and 2/24 (8%) mesotheliomas; all reactive mesothelial cells, lymphomas, sarcomas, and melanoma were negative. CD138 is a highly specific marker in the differential diagnosis of carcinoma vs. mesothelioma. Distinct membranous staining without background staining of most inflammatory cells makes CD138 an ideal marker for cell-block preparations of fluids/effusions. It should be an integral component of the epithelial-mesothelial antibody panel.

Cytomorphologic features of fine-needle aspiration of metastatic and recurrent melanoma.

Melanoma is an aggressive malignancy with a growing prevalence. Although early detection and excision offer a potential cure, recurrences and metastases are not uncommon. Fine-needle aspiration (FNA) can play a vital role in their detection as a relatively noninvasive, rapid, and economical alternative for tracking disease evolution. Prior clinical history and classic cytological features of melanoma (loosely cohesive smear pattern and single cells with large nuclei, prominent nucleoli, and melanin pigment) aid in cytological diagnoses. However, not all melanomas contain melanin pigment or characteristic cytologic features. We examined a large series of melanoma cases to determine the incidence of melanin pigment, the most common cell morphology, and the presence or absence of apoptosis/necrosis associated with this highly aggressive neoplasm.

Overexpression of p16INK4A in liquid-based specimens (SurePath) as marker of cervical dysplasia and neoplasia.

Human papillomavirus (HPV) is recognized as a causal agent for cervical carcinomas. Assimilation of HPV oncogenes E6 and E7 into the host DNA promotes upregulation of cyclin dependent kinase inhibitor (CDKI) p16(INK4A), detectable by monoclonal antibody in the developing cervical cancer cells. The aim of this study was to 1) develop a protocol for p16(INK4A) immunocytochemical staining on SurePath preparations, and 2) determine its utility as an HPV marker on a spectrum of cervical reactive and neoplastic lesions. Seventy-two specimens consisting of 28 nonneoplastic/nondysplastic cases (NN), one reactive glandular cells (RGC), 27 low-grade squamous intraepithelial lesions (LSIL), 10 high-grade squamous intraepithelial lesions (HSIL), one squamous cell carcinoma (SCCA), four atypical glandular cells (AGUS), and two adenocarcinomas (ADCA) were reprepped by SurePath and antibody to p16(INK4A) applied at 1:100 dilution using the Dako Envision + System on the Dako Autostainer. Expression of p16(INK4A) within the nucleus principally and cytoplasm of at least 10-15 cells was considered positive. All initial Papanicolaou-stained discrepant cases (p16(INK4A) positivity of NN and RGC cases and lack of reactivity in LSIL, HSIL, and AGUS) were reviewed. Nine of ten (90%) HSIL, one (100%) SCCA, 21/27 (78%) LSIL, and some reactive and inflammatory specimens demonstrated the presence of p16(INK4A). Reevaluation of discrepant cases revealed that several were underinterpreted (four NN were LSIL, one RGC was AGUS) or overinterpreted (one LSIL was NN). Following reassessment, false-positive staining was present in only 1/25 (1.4%) NN. Six of 30 (20%) LSIL lacked p16(INK4A) positivity. One of 10 (10%) HSIL had no staining. Two of four AGUS did not react with p16(INK4A) antibody. Both SCCA (1) and ADCA (2) had positive expression. This study confirms the intimate relationship between p16(INK4A) and HPV cytopathic effect. The p16(INK4A) immunocytochemical stain can be applied to liquid-based cervical preparations. This technique offers a more objective approach to deciphering "gray areas" of gynecologic cytopathology.

Peripheral endothelial cells are not reliable in differentiating primary benign and malignant hepatocellular lesions in fine needle aspirates of the liver.

The distinction of hepatocellular carcinoma (HCC) from benign lesions of the liver in fine needle aspiration (FNA) specimens can be problematic. In an attempt to separate well-differentiated HCC from benign hepatocellular lesions, the presence of tissue fragments displaying peripheral endothelial cells (PE) has been proposed in a previous study as a useful feature in favour of malignancy. In this study, we evaluated slides from 59 cases of liver masses undergoing FNA (19 HCC, 40 benign) and evaluated them for the presence of tissue fragments containing PE. We found that 90% of cases of HCC contained tissue fragments in which PE were either focally present or abundant. However, 68% of cases containing only benign hepatocytes also contained tissue fragments in which PE were at least focally present. In addition, it appears that within the group of benign lesions, the presence of PE was related to the overall cellularity of the specimen rather than the specific nature of the lesion. Thus, the presence of PE in tissue fragments does not, in isolation, appear to be a useful morphological feature for the separation of benign and malignant hepatocellular lesions in FNA material.