Fine needle aspiration cytology of glycogen-rich clear cell carcinoma of the breast: review of 37 cases with histologic correlation

OBJECTIVE: To analyze fine-needle aspiration cytology (FNAC) material from 37 cases of breast glycogen-rich clear cell cancer (GRCC) and correlate cytomorphologic features with histologic appearance to determine characteristics of GRCC on FNAC. STUDY DESIGN: We reviewed cytologic features of 37 cases of breast GRCC from the archives of Ege University Hospital diagnosed between 1994 and 2006. RESULTS: Thirty-seven patients with available aspirate and confirmed GRCC were identified. The female patients ranged from 32 to 81 years (mean 52 years). The initial cytologic diagnoses were adenocarcinoma for 27 and atypical or suspicious for cancer for 10. The cytologic picture was characterized by hypercellular tumor cells in loosely cohesive syncytial groups and some single cells. Most tumor cells had abundant, finely granular eosinophilic cytoplasm or foamy to clear cytoplasm with well-defined cytoplasmic membranes and moderate to marked nuclear pleomorphism with prominent nucleoli. Histologic examination confirmed all cases to be pure GRCC. ConCLUSION: Breast GRCC is a rare, distinct category with cytologic features that overlap considerably with those of other carcinomas. Awareness of variability in cytomorphologic appearance of GRCC and routine assessment for glycogen facilitate accurate diagnosis of these lesions by FNAC and enable prompt treatment of these poor-prognosis breast cancers.     

Comparative cytology of mucocelelike lesion and mucinous carcinoma of the breast in fine needle aspiration

OBJECTIVE: To study the fine needle aspiration cytology (FNAC) features of mucocelelike lesion (MLL) of the breast and to compare them to those of mucinous carcinoma. STUDY DESIGN: The fine needle aspiration (FNA) smears of 7 cases of histologically proven MLL (2 malignant and 5 benign, including 4 associated with atypical ductal hyperplasia) were reviewed and compared to those of 14 mucinous carcinoma cases. RESULTS: In all cases, grossly visible thick, mucoid material was obtained from FNA. The most important features for distinguishing benign MLL from mucinous carcinoma were: (1) scant cellularity; (2) no or rare single, intact tumor cells; (3) tumor cells arranged in cohesive monolayers; and (4) absence of significant nuclear atypia. In contrast, mucinous carcinoma in general showed higher cellularity; abundant single, intact cells; three-dimensional cellular clusters in most cases; and nuclear atypia ranging from mild to severe. CONCLUSION: Mucinous lesions of the breast should be divided into MLL and frank mucinous carcinoma based on FNAC. However, FNAC diagnosis of malignant MLL has yet to be defined. Excisional biopsy is advised for all hypocellular cases for further separation into benign and malignant MLL and to rule out the possibility of hypocellular mucinous carcinoma.     

Granular cell ameloblastoma of the jaw. A report of two cases with fine needle aspiration cytology

BACKGROUND: Fine needle aspiration cytology (FNAC) of jaw tumors has not been studied extensively. Ameloblastomas are jaw tumors that show a wide morphologic spectrum and thus may pose some diagnostic difficulties. Of the many types, granular cell ameloblastoma (GCA) is an uncommon variant that possesses distinctive features. To the best of our knowledge, there have been no previous reports on the cytologic findings of GCA. We present two cases diagnosed by FNAC. CASES: Two cases of GCA were diagnosed on cytology and subsequently confirmed on histology. Both patients presented with a large, lytic jaw tumor. FNAC smears showed characteristic granular cells along with spindle and basaloid cells. CONCLUSION: Although GCAs are rare tumors, they possess distinctive features that permit an accurate diagnosis, provided that this entity is kept in mind. This tumor has to be differentiated from cystic odontogenic lesions, epulis and granular cell myoblastoma. An accurate preoperative diagnosis also helps the surgeon to plan more extensive surgery as these tumors show a great propensity for malignant change and metastases.     

Fine needle aspiration cytology of mammary carcinoma with choriocarcinomatous features: a report of 2 cases

BACKGROUND: Neoplasms of the breast containing multinucleated giant cells (MGCs) include both benign and malignant entities, such as benign soft tissue giant cell tumors, atypical fibrous histiocytoma, sarcomas, metaplastic carcinomas and the uncommon carcinomas containing osteoclast-like giant cells (OGC). Breast carcinoma with choriocarcinomatous features (BCCF) is a distinct variant of breast cancer. CASES: We report the cytologic features, pathologic findings and immunohistochemical profile in 2 cases of this unusual variant of breast carcinoma. Two women aged 53 and 50 years women presented with a history of left and right breast lump but no local lymphadenopathy, respectively. Fine needle aspiration cytology (FNAC) of both cases revealed abundant MGC with highly pleomorphic tumor cells in the hemorrhagic necrotic background. Both of the cases were histopathologically diagnosed as BCCF. CONCLUSION: Choriocarcinomatous differentiation with multinucleated syncytiotrophoblast-like giant cells is extremely rare in breast tumors. Although rare, FNAC of breast cancer with pleomorphic MGC requires careful search for differential diagnosis; breast carcinoma with giant cell features (choriocarcinomatous features, OGC features) must be differentiated from metastatic tumors and other breast lesions containing giant cells.     

Fine needle aspiration cytology of primary non-Hodgkin's lymphoma of the tongue. A case report.

BACKGROUND: Fine needle aspiration cytology (FNAC) of extranodal non-Hodgkin's lymphoma of the tongue has rarely been described. CASE: A 47-year-old male was referred to the cytology laboratory for FNAC of a 3-cm-diameter swelling on the dorsum of the tongue, with a primary clinical diagnosis of soft tissue tumor. FNAC smears showed discrete, monomorphic, round to oval cells with scanty, deep blue cytoplasm. The nuclear margin was regular, with occasional prominent nucleoli and fine nuclear chromatin. The background showed many lymphoglandular bodies. The cells were strongly positive for leukocyte common antigen. A cytologic diagnosis of high grade non-Hodgkin's (NHL) was offered and subsequently confirmed by histopathology. CONCLUSION: Primary NHL of the tongue is relatively rare. As there are no characteristic clinical features of extranodal NHL of the tongue, FNAC may be useful for rapid diagnosis and management of such cases.     

Fine needle aspiration cytology of pseudosarcomatous reactive proliferative lesions of soft tissue

OBJECTIVE: To summarize the diagnostic features of fine needle aspiration cytology (FNAC) of pseudosarcomatous reactive proliferative lesions of soft tissue and to establish the criteria for differentiating these lesions from true sarcoma, thus allowing conservative management. STUDY DESIGN: FNA of 17 cases (13 nodular fasciitis, 2 proliferative fasciitis, 2 proliferative myositis), from 1994 to 2001, were reviewed in correlation with the clinical course or results of biopsy. RESULTS: The FNAC features of pseudosarcomatous reactive proliferative soft tissue lesions were characterized by a pleomorphic pattern of proliferative cells and the presence of ganglion cell-like cells. The proliferative cells varied widely from spindle shaped, with long cytoplasmic processes, to more plump cells, with round to oval nuclei. In spite of the large nuclei and prominent nucleoli in ganglion cell-like cells, the nuclei were cytologically benign, with thin and smooth nuclear membranes and fine chromatin. Clinically, all lesions appeared as small, superficially located, rapidly growing nodules with a short duration of symptoms. Ten cases of nodular fasciitis, one case of proliferative fasciitis and two cases of proliferative myositis had a spontaneous resolution in 1-12 weeks (mean, 4.7) following diagnosis by FNAC. All patients were well and devoid of any symptoms or signs of recurrence or metastasis in a follow-up period of 1-64 months after FNAC or biopsies. CONCLUSION: It is possible to differentiate pseudosarcomatous reactive proliferative soft tissue lesions from true sarcoma based on cytologic criteria in FNAC together with clinical correlation. All such lesions diagnosed by FNAC should be managed nonsurgically first, with follow-up. If regression does not occur within four to eight weeks, surgery should be performed.     

Fine needle aspiration cytology of hepatoblastoma. Recognition of subtypes on cytomorphology

OBJECTIVE: To delineate the cytomorphologic appearances of hepatoblastoma (HBL) in the largest series to date and to evaluate the feasibility of subtyping on fine needle aspiration cytology (FNAC). STUDY DESIGN: Papanicolaou- and May-Grünwald-Giemsa-stained smears of aspirates from 26 cases of HBL were analyzed by 2 observers. Histologic material, available in 15 cases, was correlated. A cytology grouping system was proposed on the basis of which all cases were classified. RESULTS: The ages of the patients ranged from 4 months to 9 years. Twenty-five cases were categorized as epithelial HBL, with epithelial fragments showing a trabecular arrangement and acinar formation in all, and extramedullary hemopoiesis in 20 cases. It was possible to differentiate fetal and embryonal areas on FNAC. Six cases showed only fetal elements (cytology group F), characterized by cells with abundant cytoplasm and a small, rounded nucleus resembling a normal fetal hepatocyte. The chromatin was finely granular, with a single, central nucleolus. Pleomorphism and mitoses were not seen, and the nuclear/cytoplasmic ratio was < or = 1/3. Fourteen cases showed, in addition to fetal elements, an embryonal component characterized by cells with scant cytoplasm, a pleomorphic nucleus, N/C ratio of > or = 3/1, coarsely granular chromatin and 2-4 angulated nucleoli. Mitoses were seen in these cells (1-4/1,000 cells). Of these 14 cases, 6 showed predominantly fetal and scant embryonal cells, while 8 cases showed fetal and embryonal components in equal amounts (cytology groups Fe and FE, respectively). Four cases showed predominantly embryonal cells (cytology group E). One case was unclassifiable (U). On histology, 8 of 14 cases were of mixed epithelial and mesenchymal type, but mesenchymal tissue was not seen on the corresponding cytology. The cytology grouping system correlated well with histology. One case was small cell undifferentiated HBL and resembled a round cell tumor without differentiation. Macrotrabecular arrangement was not seen on cytology but was seen on histology in 1 case. CONCLUSION: Epithelial HBL can be easily diagnosed in aspirates further classified into fetal and embryonal subtypes, which may be of prognostic relevance. The proposed cytology grouping system is effective in semiquantification of the observed subtypes.     

Primitive neuroectodermal tumor of the kidney. A report of two cases diagnosed by fine needle aspiration cytology

BACKGROUND: Primitive neurocetodermal tumors (PNETs) constitute a family of neoplasms of presumed neuroectrodermal origin most often presenting as bone or soft tissue masses. There are very few reported cases of PNET of the kidney and none diagnosed by fine needle aspiration cytology (FNAC), to the best of our knowledge, in the world literature. We present two cases of renal PNET diagnosed on cytology. CASES: Two patients with renal masses were diagnosed as having PNET on FNAC. Cytologically the tumors showed a dispersed population of malignant small round cells with focal rosette formation and perivascular arrangement of tumor cells. Immunohistochemistry on the cell blocks in both cases showed strong membrane positivity for CD99 (MIC2). Cytogenetic studies in both cases showed the characteristic t(11;22)(q24;q12) translocation, with additional chromosomal abnormalities in case 2. CONCLUSION: PNET of the kidney is a distinct entity and can be diagnosed on fine needle aspiration smears and confirmed with immunohistochemistry and cytogenetic studies. A diagnosis of PNET must be included in the differential diagnosis of renal masses in adolescents and young adults.     

Fine needle aspiration cytology of well-differentiated liposarcoma. A report of two cases

BACKGROUND: Well-differentiated liposarcoma is difficult to diagnose on fine needle aspiration cytology (FNAC) smears and may create considerable diagnostic problems. CASES: Males aged 60 and 45 years presented with a swelling in the groin and retroperitoneal region, respectively. FNAC showed large cells with multilobulated nuclei and mature-looking fat tissue. A soft tissue tumor with bizarre cells was diagnosed cytologically in case 1 and liposarcoma in case 2. Histologically, both cases were diagnosed as well-differentiated sclerosing liposarcoma. CONCLUSION: The cytologic diagnosis of well-differentiated liposarcoma should be done with caution, and the sites should be taken into consideration. Deep-seated tumors with large, bizarre, giant cells should have wide excision as they recur more frequently.     

Chondrosarcoma of the proximal femur with myxoid degeneration mistaken for chondromyxoid fibroma in a young adult. A case report

BACKGROUND: Fine needle aspiration cytology (FNAC) is effective in the diagnosis of bone tumors when combined with careful radiologic and clinical evaluation. However, cases where clinical or radiologic findings are atypical or unusual may lead to an erroneous diagnosis. CASE: A 19-year-old male presented with a pain in the left hip area that had been slowly progressive over a 10-month period. Clinical and radiologic findings suggested either giant cell tumor or chondroblastoma. The smeared aspiration specimen showed loosely cohesive, oval to round cells with moderate amounts of pale pink cytoplasm admixed with pinkish-blue, chondromyxoid material. The individual cells contained a single nucleus with evenly distributed, fine chromatin. A few osteoclastic giant cells were scattered in the smears. A cytologic diagnosis of myxoid lesion with a few giant cells, suspicious for chondromyxoid fibroma, was made. The diagnosis of chondrosarcoma was made by subsequent histologic examination. CONCLUSION: Absence of the usual clinicoradiologic features of chondrosarcoma combined with an unusual cytologic presentation in this case led to a misdiagnosis. In most centers, FNAC has achieved undisputed status as a diagnostic tool, and cytologic diagnosis often forms the basis of the therapeutic protocol. However, at some sites FNAC diagnosis is more problematic. Awareness of the limitations and pitfalls of FNAC is just as important as knowledge of the scope of FNAC in bone tumors. Tumors with chondromyxoid features provide particular difficulties.     

Measurement of subvisual changes in cervical squamous metaplastic cells for detecting abnormality.

Quantitative measures of visually normal squamous metaplastic cells exfoliated from the uterine cervix were obtained to test the hypothesis that these cells, like intermediate squamous and endocervical columnar cells, show subvisual evidence of atypia in cases of bonafide squamous intraepithelial neoplasia. The cells identified as squamous metaplastic were obtained from 14 abnormal (dysplastic) and 9 diagnostically negative cases. Although the cell populations so grouped showed no statistically significant differences in overall cell size, nuclear area or nuclear/cytoplasmic ratios, there were significant differences in nuclear and cytoplasmic densitometric features and in nuclear texture features. A combination of three features (nuclear density, texture and cytoplasmic density) permitted 76% of the cells to be categorized correctly as originating in normal versus abnormal slides. It is concluded that selected quantitative features of exfoliated metaplastic cell populations may contribute to improved diagnostic accuracy in automated screening for cervical abnormalities.     

Lymph node metastasis of soft tissue tumors: a cytomorphologic study

OBJECTIVE: To study the frequency of regional lymph node metastasis of soft tissue tumors (STT) and to evaluate the utility of fine needle aspiration cytology (FNAC) as an initial investigative modality. STUDY DESIGN: A prospective and retrospective study of over 6 years (1998-2004) was performed to look for frequency of STT metastasizing to lymph nodes. FNAC of enlarged nodes was performed as a routine outpatient procedure after obtaining complete clinical details. Histopathology and immunohistochemistry were correlated where available. RESULTS: Lymph node enlargement was seen in 23 of 241 patients with STTs, of which 19 cases showed involvement (7.88%), synchronous with primary in 12 cases and metachronous in 7 cases. The most common sites of primary tumor were the lower extremity and head and neck region with involved regional lymph nodes. STTs commonly involving lymph nodes were rhabdomyosarcoma and extraskeletal Ewing's/primitive neuroectodermal tumor (PNET); other rare tumors included malignant granular cell tumor, epithelioid hemangioendothelioma, mediastinal ganglioneuroblastoma, angiosarcoma and epithelioid sarcoma. CONCLUSION: Lymph node aspirates should be examined for alien cells, particularly smears that are paucicellular and demonstrate cystic change. Lymph node metastasis of STT is rare and influences staging, treatment and prognosis. Enlarged regional nodes should be examined with FNAC.     

Oropharyngeal chordoma diagnosed by fine needle aspiration: a case report

BACKGROUND: Due to its rarity, chordoma may be difficult to differentiate from other neoplasms with a similiar myxoid background. We describe a case of chordoma involving the oropharynx inferiorly that was diagnosed by transoral fine needle aspiration (FNA) cytology (FNAC) and confirmed by histologic studies. This appears to be 1 of the few reported applications of FNA in the diagnosis of chordoma of the oropharynx in the English-language literature. CASE: A 50-year-old male presented with nocturnal dyspnea and rare hemoptysis for 6 months. A hypodense mass was located in the left posterior side of the oropharynx. FNAC of the mass showed classic physaliferous cells with a bubbly appearance and myxoid fibrillary background. The aspirate was reported as "myxoid tumor suggestive of chordoma," as confirmed by histopathologic investigation of the excisional biopsy. CONCLUSION: The cytologic features of chordoma are quite characteristic, especially on May-Grünwald-Giemsa (MGG)-stained slides. The cytoplasmic vacuoles of the physaliferous cells and the mucoid matrix of the tumor become conspicuous on MGG staining. When Papanicolaou staining is used as the only staining procedure, the cytoplasmic vacuoles of the physaliferous cells and mucoid matrix of chordomas may be overlooked. The differential diagnosis of myxoid tumors is of utmost importance for therapy and prognosis.     

Scratch cytologic findings on surgically resected solitary fibrous tumors of the pleura

OBJECTIVE: To ascertain the cytologic characteristics of solitary fibrous tumors of the pleura (SFTPs) on smear preparations. STUDY DESIGN: Fine needle aspiration cytology (FNAC) was initially attempted preoperatively in five cases, but the specimens were inappropriate for interpretation because only a few tumor cells were obtained. Therefore, scratch smears made at the time of operation were used. Papanicolaou and immunocytochemical staining was performed in all 10 cases, 2 of which were malignant. RESULTS: As expected, cellular tumors yielded more cells. The cytologic appearance was variable, showing spindle/bipolar, dendritic/stellate and intermediate cells. Atypical cells reminiscent of sarcoma were also present in cellular, benign tumors. Highly atypical epithelioid cells were obtained in two malignant cases. Immunocytochemically, the tumor cells were positive for CD34 and vimentin and negative for cytokeratin, regardless of histologic differences and cell shape. CONCLUSION: It seems difficult to diagnose SFTPs with certainty by FNAC, partly because the cell morphology of SFTPs resembles a wide variety of heterogeneous groups of spindle cell tumors and partly because only a few tumor cells were available in the FNAC specimens in the present study. However, a cytologic diagnosis of SFTP is possible if cytologic preparations yield CD34-positive cells with spindle/bipolar or dendritic/stellate morphology.     

Cytomorphological changes after ultrasound-guided percutaneous ethanol injection in benign thyroid nodules

Objective:  To characterize the cytomorphological changes after percutaneous ethanol injection (PEI) in benign thyroid nodules, we compared the cytological features of fine needle aspiration cytology (FNAC) samples before and after PEI.
Methods:  Fifty-five cases diagnosed with adenomatous goitre (group 1, 35 cases) or cystic changes only (group 2, 20 cases) were included. In all cases, FNACs were performed by the pathologists before and after PEI. PEI was performed in all cases by a diagnostic radiologist according to the ultrasound guidelines. The following cytological features were evaluated by two pathologists: cellularity of follicular epithelial cells, background, cellular pleomorphism, nuclear/cytoplasmic (N/C) ratio, chromatin pattern, presence of nucleoli, macrophages, multinucleated giant cells, and mitosis.
Results:  In group 1, 19 cases (54%) showed changes in cellularity after PEI, with reduced cellularity in 13 cases (37%) and increased cellularity in six cases (17%). No necrotic background was observed before PEI; however, 14 cases (40%) developed necrotic background after PEI ( P  < 0.0001). Multinucleated giant cells were observed in 18 cases (51%) after PEI, which is in contrast to four cases (11%) before PEI ( P  = 0.001). In group 2, necrotic background was seen in 11 cases (55%, P  < 0.0001) and multinucleated giant cells were observed in four cases (20%) after PEI.
Conclusions:  Necrotic background and presence of multinucleated giant cells are indicative of tissue damage caused by PEI in the FNAC specimens of benign thyroid nodules. In contrast to other modalities including chemotherapy or radiation treatment for malignant tumour, no unusual cytological change is observed after PEI.     

Fine needle aspiration cytology diagnosis of lymphoproliferative disease of the breast

OBJECTIVE: To evaluate the role of fine needle aspiration cytology (FNAC) in the diagnosis of lymphoproliferative disease (LPD) of the breast. STUDY DESIGN: Over a period of 20 years (January 1982-December 2001), 13 diagnosed and/or suspected cases of LPD of the breast on FNAC were retrieved and reviewed from the files of the Cytology Laboratory, Department of Pathology, All India Institute of Medical Sciences. For each case, both May-Grünwald-Giemsa- and Papanicolaou-stained smears were reviewed along with hematoxylin and eosin-stained tissue sections and immunohistochemistry, when available. RESULTS: Of the 13 cases, 1 aspirate was from a male breast and the rest were from female. Only 12 cases with documented histology were included in the study. Five of the 12 cases were diagnosed on FNAC as high grade lymphoma, 2 as low grade lymphoma, 2 as poorly differentiated malignant tumor/lymphoma, and 1 each as Hodgkin's lymphoma, acute myeloid leukemia (AML) deposit and immature lymphoid cells, ?leukemia/lymphoma deposit. The tumors manifested mostly as an unilateral mass (10 cases), with 2 cases presenting with bilateral breast lumps. The lymph nodes were involved in 8 cases. Histologically, 2 of the 12 cases were poorly differentiated malignant tumors. Of the remaining 10 cases, 8 were documented as non-Hodgkin's lymphoma and 1 each as Hodgkin's lymphoma, mixed cellularity and AML. CONCLUSION: FNAC is an inexpensive but highly useful diagnostic tool to distinguish between primary lymphoma and carcinoma of the breast. This helps with clinical management in avoiding unnecessary surgical procedures.     

Fine needle aspiration of breast myofibroblastoma. A case report

BACKGROUND: The use of fine needle aspiration cytology (FNAC) for the diagnosis of breast diseases in men has received little attention. We report the cytologic and histologic findings of myofibroblastoma of the breast in a 52-year-old man. CASE: Smears disclosed irregular and cohesive sheets of cells, with ill-defined cytoplasm and oval nuclei containing single nucleoli. The nuclear membrane was frequently grooved, and occasional intranuclear cytoplasmic inclusions (pseudoinclusions) were also found. The background was clean and contained scarce collagenous stroma and fragments of myxoid material. To the best of our knowledge, there have been only seven previous reports of breast myofibroblastoma in which the cytologic features are well documented, and none of them mention the presence of pseudoinclusions. CONCLUSION: FNAC could suggest the diagnosis of this distinctly uncommon tumor if evaluated together with the clinical and radiologic findings.     

Fine needle aspiration cytology of lobular breast carcinoma. Comparison with other breast lesions

OBJECTIVE: To analyze the detailed cytomorphology of lobular breast carcinoma and to compare the cytologic smears of benign, borderline and infiltrating duct carcinoma. STUDY DESIGN: Fine needle aspiration cytology (FNAC) smears of histopathologically proven infiltrating lobular carcinoma (ILC), infiltrating ductal carcinoma (IDC), borderline lesions and benign breast lesions were selected for study. Detailed cytomorphologic analysis of the smears was carried out on hematoxylin and eosin- and May-Grünwald-Giemsa--stained slides, and a comparison of results was done. The various cytologic features were also graded semi-quantitatively with the numerical score; logistic regression analysis was done. RESULTS: There were 25 cases of ILC, 30 of IDC, and 10 borderline and 18 benign lesions. Cytologic diagnosis of malignancy on FNAC smears of ILC was offered in 19 cases; of them, 2 cases were diagnosed as ILC. The remaining six cases were diagnosed as borderline (four) and benign lesions (two). Overall sensitivity in detection of malignancy in ILC cases was 76%. FNAC smears of ILC showed moderate (52%) to abundant (32%) cellularity. The cells of ILC were arranged both in clusters and in dissociation (72%). Individual cells were monomorphic (40%) to mildly pleomorphic (60%), and the cells were smaller. The cells showed a smooth, regular nuclear margin; bland chromatin; and indistinct nucleoli. Indian file arrangement was frequently observed (28%). Nuclear molding (28%) and intranuclear inclusions (16%) were also noted. Intracytoplasmic lumina were seen in occasional cases. Logistic regression analysis was carried out, and a comparison between lobular carcinoma and ductal carcinoma, and borderline and benign lesions was done. Logistic regression analysis of cytomorphologic features showed that cellularity and nuclear margin irregularities were the two most important features to distinguish ILC from IDC. In comparison to borderline lesions, cell dissociation was more common in ILC. The salient cytologic features that helped to distinguish ILC from benign lesions was cell size, cellularity, cell uniformity and chromatin pattern. CONCLUSION: There are overlapping cytologic features between ILC, IDC and borderline breast lesions on FNAC smears. Logistic regression analysis may be helpful in this regard.