Glandular cell atypia on Papanicolaou smears: interobserver variability in the diagnosis and prediction of cell of origin

BACKGROUND: The 2001 Bethesda System recommended qualification of atypical glandular cells (AGC) to indicate the site of origin and separated endocervical adenocarcinoma in situ (AIS) from "AGC favor neoplastic" as a specific diagnostic category. To the authors' knowledge, the literature evaluating the reproducibility of Papanicolaou (Pap) smear diagnosis of glandular cell abnormalities with emphasis on the cell of origin is limited. The aim of the current study was to investigate whether a variety of benign to neoplastic glandular lesions can be reliably classified on Pap smear with regard to diagnosis and cell of origin. METHODS: Twenty-three conventional Pap smears (CPS) with glandular cellular changes varying from benign to adenocarcinoma (ACA) were reviewed by six observers. They were asked to categorize each smear according to cell of origin (endocervical vs. endometrial) and diagnosis (benign, AGC, or ACA). Kappa statistics were used to evaluate interobserver agreement and correlation of interobserver agreement with experience. RESULTS: There was no consensus among observers for both the origin of the cells and the diagnosis. Interobserver agreement for site was poor (kappa < 0.4) especially in the AGC category. Unanimous agreement for site was reached for 7 of 23 smears (30%). Two of five endocervical AIS were classified as endometrial and another two were classified as benign by four observers. Interobserver agreement was poor in all diagnostic categories (kappa < 0.4) and showed slight correlation with level of experience. Unanimous agreement for diagnosis was reached for only 2 smears (9%). Three of 11 (27%) smears demonstrating preneoplastic/neoplastic processes were diagnosed as benign by 3 observers. Three (25%) benign CPS were diagnosed as ACA by 2 observers. Accurate prediction of the final histologic diagnosis by observers varied from 30% to 87% and did not correlate closely with experience. CONCLUSIONS: Cytologic diagnosis of glandular lesions by CPS was problematic and suffered from significant interobserver subjectivity.     

c-Kit proto-oncogene expression in endometrial hyperplasia and endometrial cancer

Purpose

To evaluate the expression of c-kit (CD117) in endometrial hyperplasia and endometrial cancer.

Methods

Expression of c-kit in 10 normal endometrium, 18 simple endometrial hyperplasia, 16 complex endometrial hyperplasia (10 cases with atypia and 6 cases without atypia), and 6 endometrial cancer were investigated by immunohistochemistry.

Results

c-Kit expression decreased as the lesion progressed to endometrial cancer. Immunostaining was mostly focal and weak in the normal endometrium and was mostly diffuse and strong in the simple and complex endometrial hyperplasia.

Conclusions

Simple and complex hyperplastic endometrial tissues express diffuse cytoplasmic staining for c-kit and the expression decreases with the progression of the lesion.     

Effect of Bethesda 2001 on reporting of atypical squamous cells (ASC) with special emphasis on atypical squamous cells-cannot rule out high grade (ASC-H)

We compared the overall ASC rate and the outcomes for women with different categories of ASC before and after TBS 2001 to evaluate the impact of TBS 2001. Our laboratory reported ASC in four subcategories before TBS 2001; ASC, favor reactive (ASC-R), favor low-grade squamous intraepithelial lesion (SIL) (ASC-L), undetermined significance (ASC-US), and ASC-H. Since the implementation of TBS 2001, we have been reporting ASC as ASC-US and ASC-H. After TBS 2001, our ASC rate decreased from 6.2% to 4% (P < 0.0001). Before TBS 2001, ASC-R carried the same risk as ASC-US for underlying condyloma/CIN 1. Moreover, ASC-R was rarely associated with CIN 2 or 3. Before TBS 2001, ASC-H captured more low-grade (condyloma/CIN 1) and less high-grade (CIN 2, 3, and SCC) lesions compared to after TBS 2001. More women with ASC-H after TBS 2001 underwent colposcopy (80% vs. 71%, P < 0.05). Twenty-two percent of women with ASC-H required 2-4 colposcopies to identify the high-grade lesion. Our results confirm that consistent application of TBS 2001 terminology for ASC reduces the ASC rate, and better identifies women at high risk for CIN 2, 3, and SCC. In addition, ASC-H requires very close clinical follow-up as a significant percentage of women require more than one colposcopy to identify the high-grade lesion.     

Aspiration biopsy of mammary lesions with abundant extracellular mucinous material. Review of 43 cases with surgical follow-up

We reviewed 43 fine-needle aspiration biopsy (FNAB) smears with abundant extracellular mucinous material to determine whether accurate classification of mucinous lesions is achievable on FNAB: 26 had carcinoma (pure colloid carcinoma [CCA], 23; mixed CCA/invasive ductal carcinoma [IDC], 3); 17 had benign lesions on follow-up (benign MLL, 6; fibrocystic change [FCC], 6; myxoid fibroadenoma [MFA], 5). All carcinomas were identified correctly as malignant on FNAB. The initial cytologic diagnoses in benign cases were benign in 8, atypical in 8, and "suspicious" for carcinoma in 1. CCAs were moderate to markedly cellular with mild to moderate atypia and lacked oval bare nuclei. Marked nuclear atypia was confined predominantly to cases with mixed CCA/IDC. A distinct feature of CCA was thin-walled capillaries. FCCs and benign MLLs had overlapping cytologic features and showed variable cellularity and no or mild atypia. MFAs were markedly cellular with dyscohesion and variable atypia; stromal fragments and oval bare nuclei were present in every case. Mucinous lesions can be divided into 2 categories by FNAB: those that are adenocarcinomas and those that are not. CCAs have distinctive features that allow a definitive diagnosis on FNAB. Unnecessary surgery can be avoided in MFA by careful evaluation of smear characteristics. Cytologic features of FCC and MLL overlap. Owing to the documented association of MLL with carcinoma, we recommend that lesions that cannot be classified definitively as adenocarcinoma or MFA be considered for conservative excision, even in the absence of atypia.     

Fibroadenomas with atypia: causes of under- and overdiagnosis by aspiration biopsy.

Fibroadenoma (FA) is a common benign breast lesion frequently sampled by fine-needle aspiration biopsy (FNAB). Although the cytologic diagnosis is straightforward in most cases, cellular discohesion and atypia in FAs may lead to falsely atypical or positive FNAB diagnoses. Conversely, some adenocarcinomas mimic a fibroadenomatous pattern on FNAB, resulting in a false-negative diagnosis. We reviewed the cytologic and histologic findings in 25 cases with a preoperative FNAB diagnosis of FA, wherein excision was recommended based on atypia. Our aim was to analyze the spectrum of changes causing under- or overdiagnosis in such cases. The smears were assessed for cellularity, cellular discohesion, presence of dissociated intact cells and nucleoli, nuclear pleomorphism, oval bare nuclei, and stromal fragments. The histologic findings were correlated with FNAB features. At excision, 88% of FAs classified as atypical on FNAB were benign (FA with ductal hyperplasia and lactational change, myxoid FA, and other fibroepithelial lesions). Differentiating myxoid FA from colloid carcinoma was difficult due to the abundance of extracellular mucin in which the dissociated epithelial cells were floating. Two (8%) cases were carcinomas on excision; the reasons for underdiagnosis in one case reflected sampling, and in the other, interpretative error. There was one (4%) benign phyllodes tumor which lacked stromal fragments and single stromal cells on FNAB smears. The lesion was called atypical, based on the epithelial discohesion on the smears. We conclude that the majority of FAs with atypia on FNAB are benign lesions. Considering the grave consequences of a false-positive cytologic diagnosis, we recommend a conservative approach in interpreting FNAB smears which overall display a fibroadenomatous pattern.     

Cytologic features of tubular adenocarcinoma of the breast by aspiration biopsy.

Tubular adenocarcinoma is an invasive mammary adenocarcinoma associated with an excellent prognosis and a low incidence of axillary metastases. However, identification of tubular adenocarcinoma by fine-needle aspiration (FNA) biopsy has proven difficult. One hundred five patients with documented "pure" tubular adenocarcinoma were diagnosed at Tisch Hospital from August of 1992 to December of 1998. Twenty-one of these patients had an FNA before excision. We reviewed the smears of these cases and compared them with cases of fibroadenoma and fibrocystic change to identify criteria for diagnosis. Moderately to highly cellular smears with angular cellular clusters with sharp borders and oval cells outlining these clusters, dispersed single cells with minimal atypia, and the absence or paucity of dispersed bare oval nuclei in the background were features that suggest a diagnosis of tubular adenocarcinoma in our study. Attention to these features in combination with appropriate mammographic findings should preclude a false-negative diagnosis in the majority of cases of tubular adenocarcinoma diagnosed by aspiration biopsy. We point to the presence of the peripheral perpendicular cells in the characteristic tubular arrays as an important clue to the diagnosis of tubular adenocarcinoma.     

Mammary lesions diagnosed as "papillary" by aspiration biopsy: 70 cases with follow-up

BACKGROUND: The authors reviewed smears from fine-needle aspiration biopsies (FNAB) diagnosed as "papillary lesions" and correlated the cytologic findings with the final diagnoses at excision. The objective of the current study was to determine the accuracy of FNAB diagnosis of a papillary lesion in distinguishing true papillary from nonpapillary proliferations and to evaluate cytologic criteria for the distinction of papillomas from true papillary malignancies and their cytologic look-alikes. METHODS: The cytopathology database at the New York University Medical Center was searched for women who underwent surgical excision after a breast FNAB diagnosis of a papillary lesion. The FNAB smears and corresponding slides from excisional biopsies were reviewed. The smears were evaluated and graded for the following features: cellularity, architecture, presence of fibrovascular cores, single cells, columnar cells, cellular atypia, myoepithelial cells, foamy histiocytes, and apocrine cells. The F test was used to determine the statistical significance of differences between true benign papillary lesions (papilloma) and adenocarcinomas (in situ and invasive). RESULTS: At the time of excision, 46 (66 %) cases were benign (23 solitary intraductal papillomas, 6 intraductal papillomatosis, 11 examples of fibrocystic change, and 6 fibroadenomas) and 24 (34 %) were malignant (1 low-grade phyllodes tumor [PT], 23 ductal in situ and invasive carcinomas). Of the 23 carcinomas, 3 (13 %) were classified as benign papillary lesions on FNAB and 19 (86 %) were classified as either atypical or suspicious. One case of low- grade PT originally was classified as benign on FNAB. There were four false-negative diagnoses; two were due to sampling and two to interpretative errors. A portion of the lesions classified as papillary were fibroadenomas and examples of fibrocystic change on excision and all of these were correctly classified as benign on FNAB. Of the histologically proven papillomas, 62% were correctly classified as benign on FNAB and none were designated as being positive for malignancy. Statistically significant features of distinction between papillomas and carcinomas included cellularity (P = 0.016), cellular atypia (P = 0.0053), and the presence of cytologically bland columnar cells (P = 0.04). Low-grade ductal carcinoma in situ (cribriform and micropapillary types) and tubular carcinoma represented the most difficult differential diagnostic problems. CONCLUSIONS: A significant portion of lesions displaying a papillary pattern on FNAB are nonpapillary on follow-up. Among benign processes, fibrocystic change and fibroadenoma may closely simulate papilloma on cytology. However, in spite of the overlapping features of true papillary lesions and their cytologic look-alikes, the majority can be classified accurately into benign or atypical (and above) categories by FNAB. Lesions that fall short of a definitive benign diagnosis should be placed into an indeterminate category. This approach will guide the surgeon to provide better patient management.