Mesothelioma Symposium 11.30–12.30 Tuesday 16 September 2003. Cytopathology of malignant mesothelioma

The diagnosis of malignant mesothelioma on the cytology of serous effusions is a two‐phase process. First is to determine that the effusion is malignant based on morphological features such as a highly cellular fluid with many large three dimensional cell aggregates, and/or the recognition of minor malignant criteria including prominent cell engulfment, uniformly present very prominent nucleoli, or the finding of very large (giant) cells. In cell block sections, strong positive staining with EMA often with cell membrane accentuation provides compelling support for a cytological diagnosis of malignancy. Second is to recognize that the malignant cells have a mesothelial phenotype and do not represent metastatic malignancy (usually adenocarcinoma). Criteria in support of mesothelioma include the lack of a ‘two cell’ population, that is one native (mesothelial) and one foreign (metastatic), cells with abundant dense staining cytoplasm, the presence of ‘windows’ where mesothelioma cells lie in close apposition and intracytoplasmic glycogen presenting either as small peripheral vacuoles on MGG stained smears or large yellow refractile crescents on Papanicolaou stained smears. In addition, mesothliomas often possess connective tissue stromal cores occurring as either well‐formed collagen within papillary aggregates or lying free as pink (MGG) or light green (Pap) amorphous material in the background of the smear or in loose association with mesothelioma cells. Finally small orange staining squamous‐like cells can occasionally be identified and sometimes this may be a very prominent finding and has resulted in the false impression of a squamous cell carcinoma. Almost certainly these cells represent apoptotic tumour cells. The connective tissue mucin hyaluronic acid may be found as a net‐like pattern in the smear background or as large hard‐edged magenta‐stained vacuoles on MGG‐stained smears. Cell block sections provide architectural information and it is usually possible to separate mesothelioma aggregates with their cuboidal cells, central nuclei and abundant dense cytoplasm arranged in solid, papillary or hollow clusters from those of adenocarcinoma with less dense, often foamy cytoplasm, often composed of columnar cells with elongated nuclei. Aggregate form in adenocarcinoma can be variable but true acini are a rare finding. These cell block sections provide an ideal medium for histochemistry (PAS with and without diastase digestion) and immunocytochemistry. By using a panel of antibodies (Calretinin and CK 5/6, BerEp4, CEA, B72.3) it is almost always possible to distinguish mesothelioma from metastatic adenocarcinoma. Calretinin and CK 5/6 positive staining and absent staining with BerEp4, CEA and B72.3 is considered diagnostic of mesothelioma.     

The Anal Pap Smear: Cytomorphology of squamous intraepithelial lesions

BACKGROUND: Anal smears are increasingly being used as a screening test for anal squamous intraepithelial lesions (ASILs). This study was undertaken to assess the usefulness and limitations of anal smears in screening for ASILs. METHODS: The cytomorphological features of 200 consecutive anal smears collected in liquid medium from 198 patients were studied and findings were correlated with results of surgical biopsies and/or repeat smears that became available for 71 patients within six months. RESULTS: Adequate cellularity was defined as an average of 6 or more nucleated squamous cells/hpf. A glandular/transitional component was not required for adequacy. Dysplastic cells, atypical parakeratotic cells and bi/multinucleated cells were frequent findings in ASIL while koilocytes were infrequent. Smears from LSIL cases most frequently showed mildly dysplastic and bi/multinucleate squamous cells followed by parakeratotic cells (PK), atypical parakeratotic cells (APK), and koilocytes. HSIL smears contained squamous cells with features of moderate/severe dysplasia and many APKs. Features of LSIL were also found in most HSIL smears. CONCLUSIONS: In this study liquid based anal smears had a high sensitivity (98%) for detection of ASIL but a low specificity (50%) for predicting the severity of the abnormality in subsequent biopsy. Patients with cytologic diagnoses of ASC-US and LSIL had a significant risk (46-56%) of HSIL at biopsy. We suggest that all patients with a diagnosis of ASC-US and above be recommended for high resolution anoscopy with biopsy.     

Fine needle aspiration cytology (FNAC) of mammary granular cell tumour: a report of three cases

This report describes the FNAC findings in three cases of granular cell tumour of the breast. The patients comprised two females aged 59 and 62 years and one male aged 28 years. All patients presented with a breast lump which was clinically and radiologically suspicious of malignancy. FNAs yielded moderately cellular specimens which on cytologic examipation consisted of groups of cells and single cells with small regular nuclei and abundant granular cytoplasm. Bare nuclei were also present but these did not have the characteristic bipolar appearance of myoepithelial cells. In two cases there was a granularity to the background. The aspirates were reported as equivocal or atypical, probably benign, and surgical biopsy was performed. Histological examination showed typical benign granular cell tumours with strong positive staining for S-100 protein. Pathologists should be aware that granular cell tumour may occur in or around the breast and should consider this diagnosis in aspirates containing a population of cells with regular nuclei and abundant granular cytoplasm. The main cytologic differential diagnoses are likely to be apocrine cells and histiocytes. The suspicion of a granular cell tumour should be heightened when these features are present in an aspirate from a clinically and radiologically suspicious mass. These cases highlight the role of the triple approach encompassing clinical, radiological and cytological features in the assessment of a breast lesion.     

Mucoepidermoid carcinoma of the salivary gland in pleural fluid. A case report

The cellular features of mucoepidermoid carcinoma of submandibular gland origin observed in pleural fluid are presented. The pleural fluid contained predominantly atypical spheroid cell clusters accompanied by numerous mesothelial cells. The cells had round nuclei with conspicuous nucleoli, coarsely granular chromatin and abundant cytoplasm with vacuoles. The cellular features of the malignant cells in the pleural fluid were correlated with the histology of the parent lesion.     

Hansen's disease (leprosy). Diagnosis by aspiration biopsy of lymph nodes

A 61-year-old male native of Mexico presented with generalized enlargement of lymph nodes. Fine needle aspiration (FNA) biopsy established lepromatous leprosy as the cause of the lymphadenopathy. The cytologic findings included abundant, frequently multinucleated histiocytes (globus cells), the cytoplasm of which showed multiple vacuoles; cytoplasmic membrane-bound vacuoles were seen free in the background. The vacuoles contained large numbers of acid-fast bacilli. Globus cells, while characteristic, are not specific for Mycobacterium leprae infection and are seen in certain atypical mycobacterioses in immunodeficient patients. This appears to be the first report of lymphadenopathy due to lepromatous leprosy in which the diagnosis was made by FNA biopsy. The immunologic spectrum of leprosy is correlated with clinical and pathologic findings, and the need to remember infectious processes in evaluating lymphadenopathy and the value of reserving air-dried and alcohol-fixed smears for special stains are emphasized.     

Keratinized squamous cells in fine needle aspiration of the brain. Cytopathologic correlates and differential diagnosis

OBJECTIVE: To analyze the differential diagnosis when keratinized squamous cells are found in a brain aspirate. STUDY DESIGN: Twenty cases of brain aspirates with keratinized squamous cells were retrieved (1982-2001). Diagnoses included craniopharyngioma (CP) (n = 11), metastatic squamous cell carcinoma (SCC) (n = 5), epidermoid cyst (EC) (n = 3) and Rathke cleft cyst (RCC) (n = 1). Aspirates were obtained under stereotactic radiologic (CT) guidance. Smears were stained with Diff-Quik or Papanicolaou stain, and cell block sections were stained with hematoxylin and eosin. Radiologic and histopathologic correlation with subsequent resection specimens was performed in selected cases. RESULTS: CP showed cellular smears with numerous keratinized squamous cells in a background of degenerated cellular and keratinaceous debris. Also noted were clusters of anucleate squamous cells, multinucleated giant cells, histiocytes, calcified debris and characteristic fragments of basaloid epithelial cells. Metastatic SCC showed single cells and tissue fragments of markedly atypical and focally keratinized cells with enlarged, hyperchromatic nuclei; prominent pleomorphism in a background of necrotic cellular debris and acute inflammatory exudate. EC showed numerous isolated keratinized squamous cells often with prominent keratohyaline granules and occasional parakeratotic cells in a relatively clean background. RCC showed single cells and aggregates of benign-appearing squamous cells admixed with numerous anucleate squames and hemosiderin-laden macrophages. Glandular-type epithelium was present only rarely. CONCLUSION: Squamous cell-containing lesions in the brain present a spectrum of pathologic entities. Although they all display the common morphologic denominator of keratinizing squamous cells, subtle cytomorphologic differences exist in these lesions, permitting an accurate cytopathologic diagnosis. Clinicardiologic features and anatomic location of the tumor in the brain are additionally helpful.     

Solitary fibrous tumour: a diagnostic challenge for the cytopathologist

N. Gupta, A. Barwad, K. Katamuthu, A. Rajwanshi, B. D. Radotra, R. Nijhawan and P. Dey Solitary fibrous tumour: a diagnostic challenge for the cytopathologist Background: Solitary fibrous tumour (SFT) is an uncommon spindle cell tumour that can occur in a variety of locations. Cytological features of this tumour have only rarely been reported in the literature. We describe the cytomorphological features of SFT with an emphasis on diagnostic pitfalls. Methods: We retrieved nine cases of histopathologically proven SFT. Three cases had sampling error with inadequate smears and, therefore, six cases with adequate cellularity were analysed for cytological findings. The cytomorphological features and the differential diagnoses on fine needle aspiration cytology (FNAC) are discussed. Results: No definitive cyto‐diagnosis of any of these cases was possible because of the morphological overlap with various soft tissue tumours and other tumour types. There was one false‐positive case, in which the possibility of sarcoma was suggested due to the presence of scattered atypical cells. Cytologically, the smears from the SFTs showed spindle to plump cells embedded in metachromatically staining dense ropy collagen material. The cells usually had oval to spindle shaped nuclei, bland chromatin and wavy elongated pale staining cytoplasm. Conclusion: A diagnosis of SFT on cytology smears is challenging. Careful attention given to certain cytological features in an appropriate clinicoradiological setting and application of immunochemistry, including CD34 and CD99 immunostaining on cytological samples, can help in the diagnosis of SFT in some cases. It is important to consider cytological overlaps of this tumour in order to avoid false‐negative or false‐positive results.     

Centrifugal separation of carcinoma or atypical cells in voided urine

A simple density gradient method was used to separate atypical and cancer cells from non-cancer cells in voided urine from patients with transitional cell atypia (moderate and grave atypia) and bladder cancer (squamous cell carcinoma and transitional cell carcinoma). Prior to cell separation, the Saccomanno preserved cells were dispersed by homogenization. After cell separation (5 min x 1400 rpm), atypical and cancer cells were enriched up to 20-fold. Also, most of the leucocytes (68-98%) and squamous cells (47-82%) were absent from density gradient specimen fractions containing the largest percentages of atypical and cancer cells. Peak purity ranges of atypical or cancer cells from different sample classes showed a large degree of overlap. This permitted the pooling of density gradient fractions enriched for atypical or cancer cells, thus increasing the efficiency of the method. Also, following centrifugation, the Papanicolaou-stained specimen fractions showed less background staining than the unprocessed controls, and the cells retained diagnostic morphologic features. We infer that this method may be a useful, low-cost approach for the morphologic study of developing cancers, not only from the urinary bladder, but also from the respiratory tract.     

Serous effusion cytology of extranodal natural killer/T-cell lymphoma

X.‐Y. Su, J. Huang, Y. Jiang, Y. Tang, G.‐D. Li and W.‐P. Liu Serous effusion cytology of extranodal natural killer/T‐cell lymphoma Objective: Extranodal natural killer/T‐cell lymphoma, nasal type (ENKTCL‐N), is a rare form of lymphoma that typically occurs at extranodal sites. It is one of the most common extranodal lymphomas in China. Literature on effusions and cytological findings relating to ENKTCL‐N is limited. We studied five consecutive cases of ENKTCL‐N effusions collected over a 3‐year period. The cytomorphological, immunocytochemical and molecular biological features were evaluated with literature review. The purpose of this study is to discuss how to diagnose ENKTCL‐N cytologically in effusions. Methods: Smears and cell block sections were reviewed for each case. Immunocytochemistry was performed on 4‐μm paraffin sections. Antibodies used were as follows: cCD3 (intracytoplasmic CD3), CD45RO, surface CD3, CD20, CD79a, CD56, TIA‐1, granzyme B, CD30, CD99, TdT and Ki‐67. In situ hybridization for EBER1/2 (EBER‐ISH) and T‐cell receptor γ (TCRγ) gene rearrangement were performed for all cases. Results: Large to medium‐sized tumour cells with pleomorphic nuclei and coarse chromatin were found in a necrotic background in all cases. The cytoplasm of the tumour cells was scant to moderately abundant with occasional cytoplasmic projections; in Giemsa‐stained smears, fine granules were present in some tumour cells. Mitotic figures were frequent. The tumour cells were all positive for CD56, granzyme B, TIA‐1 and cCD3, and were negative for surface CD3, CD20 or CD79a, CD99 and TdT. The MIB index was 50–80%. Epstein‐Barr virus‐encoded RNA (EBER) hybridizing signals were detected for most neoplastic cells. The T‐cell receptor gamma gene rearrangement analysis showed germ‐line configuration, except for one case. Conclusions: Effusion cytology may be appropriate for establishing the diagnosis of ENKTCL‐N, particularly for patients in whom tissue biopsy is not possible.     

Effects of fractionated X-irradiation on subsequent response to acute X-irradiation in two human tumour cell lines in vitro

The exposure of two human tumour cell lines, one derived from a squamous cell carcinoma of the tongue (HN-1) and the other from an adenocarcinoma of the breast (MCF-7), to fractionated X-irradiation in vitro, resulted in altered sensitivity to subsequent acute X-irradiation exposure in the former but not the latter tumour cell type. The X-ray-pretreated HN-1 cells, designated HN-1/DXR11 cells, showed a significantly increased sensitivity to X-irradiation with a D0 of 0.97 Gy, compared with a figure of 1.39 Gy for the parental cells. No significant changes were noted in a number of basic cell kinetic or biological parameters in the X-ray-pretreated cells. However, this enhanced X-ray sensitivity in the HN-1/DXR11 cells was associated with decreased cellular levels of total intracellular glutathione. These findings are consistent with the theory that intracellular thiols are involved in protection from radiation damage. This is one of the first observations that prior exposure to X-irradiation can modify subsequent responses to acute X-irradiation treatment in human tumour cells.     

Cytologic diagnosis and subtyping of rhabdomyosarcoma

atahan s,., aksu ö. and ekinci c. (1998) Cytopathology 9, 389–397
Cytologic diagnosis and subtyping of rhabdomyosarcoma
We reviewed the cytological findings of 38 cases of rhabdomyosarcoma (RMS) with histological confirmation performed during a period of 15 years and proposed a morphological subtyping based on the most prominent cytologic features. Seventeen of these cases were alveolar, 14 cases embryonal, and seven botryoid subtypes. From these cases, a total of 43 samples, of which 37 were fine needle aspiration (FNA) biopsies and six were touch imprints, were evaluated. Detailed cellular features were identified which enabled differentiation into histological subtypes. In the alveolar RMSs, most tumour cells were small and lymphocyte-like, having finely granular chromatin. The finding of cells with more abundant cytoplasm, eccentrically located nuclei and bi/multinucleated tumour cells in a background of mucosubstance helped in the differential diagnosis. Two cell types, including large, tadpole or ribbon-shaped tumour cells and small, round cells with scant cytoplasm, were seen in embryonal RMSs. In botryoid RMSs, a cell type with tightly grouped nuclei within elongated cytoplasm similar to a myotubular structure was observed in addition to the two cell types of embryonal RMSs. We conclude that with experience it will be possible to subtype these tumours by cytologic examination alone.     

ASCUS, mature metaplastic type. Cytologic diagnosis and follow-up

OBJECTIVE: To study the cytologic criteria for follow-up of mature metaplastic cells within the atypical squamous cells of undetermined significance (ASCUS) category. STUDY DESIGN: Squamous epithelial abnormalities between January 1994 and June 1997 at our institution totaled 2,632 and included squamous carcinoma (1), high grade squamous intraepithelial lesions (278), low grade squamous intraepithelial lesions (875) and ASCUS (1,478). From the ASCUS group, 134 (9.06%) were metaplastic; 89 were selected for review. Criteria for case selection were follow-up with tissue biopsy or at least two Pap smears and no previous epithelial abnormality. Patients ranged from 27 to 70 years of age. Parameters tabulated included number of abnormal cells per slide, their architecture, cell size, shape, cytoplasmic hue and texture, nuclear size and contour, chromatin pattern and nucleoli. Additionally, specimens were reviewed for hormonal status and inflammation. The findings were correlated with follow-up data. RESULTS: Cells generally appeared single or in loose, monolayered sheets of three to seven cells per group. The cells were well demarcated, polygonal or oval and ranged from 11 to 30 microns with cyanophilic or eosinophilic thickened cytoplasm. The round to oval nuclei with slight irregularity showed a minimally increased nuclear/cytoplasmic ratio with stippled chromatin. Upon review, 69 smears were confirmed as ASCUS-M. Follow-up revealed 42 with benign findings, 9 with persistent ASCUS/ASCUS-M and 18 with low grade squamous intraepithelial lesions. CONCLUSION: In mature metaplastic cells with minimal atypia in patients with no previous or concurrent dysplasia, the follow-up details were similar to those described for ASCUS-superficial/immediate squamous cells. These patients could be followed conservatively.     

Pitfalls in the diagnosis of herpes simplex infection in respiratory cytology

OBJECTIVE: To evaluate the prevalence and potential pitfalls in making an accurate diagnosis of respiratory herpetic infection. STUDY DESIGN: Eighteen cases with the diagnosis of herpes simplex virus (HSV) infection were identified from a total of 7,501 (0.24%) respiratory specimens. All cases were evaluated for classic cytomorphologic features of HSV infection and associated cytologic findings. The parameters studied included number of cells with HSV cytopathic effect, intranuclear inclusions, multinucleation, presence of atypical squamous cells, reparative changes, presence and degree of inflammation and associated obscuring factors. RESULTS: Only a minority of cases (28%) had numerous cells with classic viral cytopathic change. Four (22%) of 18 cases showed atypical squamous cells, and 5 (28%) revealed reparative changes. The majority of the cases were associated with inflammation, which was severe in 4 cases (22%). Blood and degenerative changes obscured the cytologic findings in 3 cases (17%). One case showed a necrotic background. CONCLUSION: Due to the low prevalence of HSV infection in respiratory cytology, a high index of suspicion is necessary for an HSV diagnosis. Pitfalls for a false negative diagnosis include limited number of cells with viral cytopathic change, only mononuclear cells with viral changes and obscuring inflammation or blood. Pitfalls for a false positive diagnosis of malignancy include atypical keratinized squamous cells, atypical repair, cellular degeneration and necrotic background.     

Glassy cell carcinoma of the uterine cervix. Report of a case with cytohistologic and immunohistochemical study

BACKGROUND: Glassy cell carcinomas of the uterine cervix are poorly differentiated carcinomas composed of cells with a large, round to oval nucleus containing one or multiple prominent nucleoli, finely vacuolated eosinophilic to amphophilic cytoplasm and distinct cell borders. These cells occur in sheets and chords, with fibrovascular septae presenting a mixed inflammatory infiltrate. This neoplasm has a poor response to radiotherapy and a worse prognosis than the usual types of adenocarcinoma and squamous cell carcinoma. There are few reports on the cytologic and histopathologic features of this neoplasm. CASE: A 56-year-old woman presented with a large, exophytic cervical tumor. Exfoliative cytology showed clusters of cells and single cells with large, round to oval nuclei, with one or multiple nucleoli and moderate to large, finely granulated cytoplasm with distinct cell borders. The background of the smears had a polymorphous inflammatory infiltrate, necrotic debris and proteinaceous material. A high mitotic rate was observed, as were rare bizarre and atypical multinucleated cells. There was no evidence of koilocytes. These findings were highly suggestive of glassy cell carcinoma and were confirmed by the histologic and immunocytochemical findings, with positivity for cytokeratin (MNF116), vimentin and carcinoembryonic antigen and negativity for HMB-45. CONCLUSION: Glassy cell carcinoma of the cervix presents a cytologic picture that can be highly suggestive of the diagnosis in typical cases; however, in difficult cases ancillary techniques, such as immunocytochemistry, as well as histologic findings might confirm the diagnosis.     

Atypical squamous cells as a diagnostic pitfall in pulmonary Wegener's granulomatosis. A case report

BACKGROUND: Wegener's granulomatosis (WG) is characterized by systemic, necrotizing, granulomatous inflammation accompanied by vasculitis. It classically involves the triad of the upper respiratory tract, lungs and kidneys. Isolated pulmonary lesions of WG may present in some patients as pulmonary masses, simulating neoplasms. The features of WG can be suggested by cytologic study. Atypical epithelial cells associated with WG have previously been reported as a cause of a false positive diagnosis of bronchoalveolar carcinoma. CASE: In this case the cytologic findings included atypical squamous cells in a background of acute, chronic and granulomatous inflammation. In several respiratory specimens the atypical squamous cells were incorrectly interpreted as diagnostic of squamous cell carcinoma. The correct diagnosis of WG was confirmed with open lung biopsy, which demonstrated necrotizing granulomatous inflammation with geographic necrosis and associated vasculitis. CONCLUSION: Markedly atypical squamous cells mimicking squamous cell carcinoma can be found accompanying the inflammatory process associated with WG and are a possible diagnostic pitfall. The possibility of WG as well as other inflammatory processes should always be considered in the differential diagnosis of squamous cell carcinoma of the lung. This case is the only reported case of WG in which atypical squamous cells were a diagnostic pitfall, initially suggesting a diagnosis of squamous cell carcinoma.     

Fine needle aspiration (FNA) cytology of Rosai Dorfman disease

deshpande v and verma k. (1998) Cytopathology 9, 329–335
Fine needle aspiration (FNA) cytology of Rosai Dorfman disease
Rosai Dorfman disease (sinus histiocytosis with massive lymphadenopathy (SHML)) is a benign self-limiting disorder that commonly involves the lymph nodes. We reviewed eight cases of this entity aiming to document the cytomorphological features. Of the eight cases, a preoperative diagnosis was suggested in seven cases. Pertinent features included: numerous large histiocytes with prominent emperipolesis (documented by a halo around the cell), fine vacuoles in the cytoplasm and lymphocytes and plasma cells in the background. In some cases the histiocytes showed atypia. In one biopsy-proven case a diagnosis of Hodgkin's was suggested, emphasizing the pitfalls associated with the FNA diagnosis of this lesion.     

Basement membrane material and tigroid background in a fine needle aspirate of clear cell adenocarcinoma of the cervix. A case report

BACKGROUND: Although cytologic findings of clear cell adenocarcinoma of the female genital tract have been reported sporadically, the background on the smear has received little attention. CASE: A 16-year-old female had a large, necrotic mass in the cervix. As cervical brushing cytology and a punch biopsy of the mass could not make a definitive diagnosis, fine needle aspiration cytology was performed from the mass. The smears revealed loose, three-dimensional clusters and sheet arrangements of atypical cells. Dispersed atypical cells were also seen. The atypical cells were large and had abundant, weakly stained cytoplasm and round or oval nuclei with large nucleoli. There were a few tumor cells with clear cytoplasm and distinct cell borders in Papanicolaou-stained smears. The background in Diff-Quik-stained smears revealed a tigroid background and basement membrane material. CONCLUSION: The malignant tumor, revealing both a tigroid background and basement membrane material, seems to have been clear cell adenocarcinoma. Both features are diagnostic clues to clear cell adenocarcinoma in the female genital tract. Our case indicates that aspiration cytology is also an effective method of diagnosing a cervical tumor when the tumor is polypoid and the surface is extensively necrotic.     

Pitfalls in the diagnosis of Wegener''s granulomatosis on fine needle aspiration cytology

OBJECTIVE: To review the clinical and pathological findings in six suspected cases of Wegener's granulomatosis (WG) and highlight the diagnostic difficulties faced by the cytopathologist. METHODS: Retrospective review of records of the Cytopathology Department to identify patients who underwent image-guided transthoracic pulmonary fine needle aspiration cytology (FNAC) for pulmonary lesions of suspected WG and those who were subsequently confirmed to have WG. Detailed evaluation of cytomorphological features was carried out. RESULTS: A total of six cases were identified in whom the initial procedure to obtain a pathological diagnosis was transthoracic FNAC. In one case, atypical squamous cells on cytology initially suggested a diagnosis of squamous cell carcinoma while in another a diagnosis of WG was made on cytology; however, a subsequent lung biopsy revealed silicosis. CONCLUSION: Acute inflammation and necrosis are the most consistent cytopathological findings in WG. In selected cases FNAC can provide supportive pathological evidence to establish a diagnosis of WG.     

Interobserver concordance in the assessment of features used for the diagnosis of cervical atypical squamous cells and squamous intraepithelial lesions (ASC‐US,ASC‐H,LSIL and HSIL)

G. Bigras, J. Wilson, L. Russell, G. Johnson, D. Morel and M. Saddik
Interobserver concordance in the assessment of features used for the diagnosis of cervical atypical squamous cells and squamous intraepithelial lesions (ASC‐US, ASC‐H, LSIL and HSIL) Objectives: Given the well‐known poor reproducibility of cervical cytology diagnosis, especially for atypical squamous cells of undetermined significance (ASC‐US) and low‐grade squamous intraepithelial lesion (LSIL), this study surveyed reproducibility in the assessment of individual cytomorphological features. Methods: One hundred and fifty cells or groups of cells, with a variety of morphological appearances, including normal cells, high‐grade squamous intraepithelial lesion (HSIL), LSIL, ASC‐US and ASC cannot exclude HSIL (ASC‐H), were precisely marked on 150 different liquid‐based cytological preparations. They were analysed by 17 observers who assessed 17 cytological features including nuclear features (chromatin texture, nuclear outline, nuclear shape, etc.), cytoplasmic features (cell shape, cytoplasmic staining, cytoplasmic clearing, etc.) and group characteristics (nuclear polarity, cellular density, etc.). A total of 43 350 data scores were collected in a database using a web‐based survey. Kendall’s W and relative entropy indexes were utilized to compute concordance indexes of respectively ordinal and nominal variables. Results: Nuclear features have significantly lower reproducibility (0.46) compared with other cytological features (0.59). The feature with least agreement is assessment of chromatin texture. A small but significant difference in concordance was found between two subsets of observers with different levels of experience. Conclusion: Most previous studies assessing reproducibility of cytological diagnoses show, at best, moderate reproducibility among observers. This study focused on agreement regarding the presence of constituent morphological features used to recognize dyskaryosis and various grades of squamous intraepithelial lesions. A map of reproducibility indexes is presented that highlights, for daily practice or teaching, the robustness of features used for cytological assessment, recognizing that diagnosis is always based on a combination of features.