A morphologic and morphometric study of cells from colloid carcinoma of the breast obtained by fine needle aspiration. Distinction from other breast lesions

Morphologic and morphometric studies were carried out on eight cases of pure and mixed colloid carcinoma of the breast initially diagnosed by fine needle aspiration (FNA). Key morphologic features included (1) cellular smears, (2) single cells, loose aggregates and cohesive groups of cells bathed in a mucinous background, (3) single cells displaying nuclear eccentricity and (4) little variation in nuclear size or shape, with bland-to-accentuated chromatin and rare nucleoli. These morphologic features are compared with those observed in pregnancy adenoma, lobular carcinoma, fibroadenoma, ductal carcinoma and medullary carcinoma. A morphometric study employing the major and minor axes of the nucleus, its axis product and axis ratio was also performed. Statistical treatment confirmed that the nuclear axis product (a size factor) distinguished colloid carcinoma from the other breast lesions, except the small-cell type of ductal carcinoma. Furthermore, the nuclear axis ratio (a shape factor) discriminates pregnancy adenoma and small-cell ductal carcinoma from the other breast lesions studied. By combining morphologic and morphometric criteria, one can specifically separate colloid carcinoma from the other breast lesions when examining smears obtained by FNA. Since colloid carcinoma is usually composed of cells with a relatively benign-appearing cytomorphology, the importance of recognizing this entity in fine needle aspirates is emphasized.     

Automated image morphometry of lobular breast carcinoma

OBJECTIVE: To analyze the role of automated image morphometry (AIM) in distinguishing infiltrating lobular carcinoma (ILC) of the breast from benign, borderline and infiltrating ductal carcinoma (IDC). STUDY DESIGN: Only histopathologically proven lobular carcinoma, ductal carcinoma, borderline lesions and benign breast lesions were selected for the study. There were 19 cases of ILC and 30 cases of IDC, 20 cases of benign lesions (fibroadenoma, 18; fibrocystic disease, 1; and fibroadenosis, 1); 10 cases were borderline lesions (mild epithelial hyperplasia, 3; moderate epithelial hyperplasia, 2; florid epithelial hyperplasia 4; intraductal papillary carcinoma, 1). In all cases hematoxylin and eosin-stained slides were used for AIM. At least 100 cells from each case were subjected to analysis randomly with an image cytometer with Leica Quantimet 600 software (Cambridge, England). Nuclear area, diameter, perimeter, convex perimeter, convex area and roundness were measured in each case with random, unbiased selection of cells and 40 x objectives (one pixel = 0.46 microm). AIM data on the cases were analyzed in relation to final cytologic diagnosis. RESULTS: All the nuclear morphometric features of ILC were much lower than those of IDC and borderline lesions, whereas nuclear morphometric data on ILC were only marginally more than those on benign cases. ANOVA showed that mophometric data were significant (P < .05) in all the variables between ILC and IDC. However, there was no significant difference between ILC, and borderline and benign cases. CONCLUSION: Image morphometry may be useful in distinguishing ILC from IDC on cytologic smears. However, morphometric data may not be helpful in distinguishing benign and borderline lesions from ILC.     

Computerized morphometric study on fine needle aspirates of cellular follicular lesions of the thyroid

OBJECTIVE: To investigate the value of computerized nuclear morphometry in the differential diagnosis of cellular follicular lesions of the thyroid cytologically diagnosed on fine needle aspiration (FNA) smears. STUDY DESIGN: Sixty cases of FNA thyroid smears were cytologically diagnosed and classified as follows: 30 cases of follicular carcinoma, 20 cases of cellular hyperplastic nodules and 10 cases of follicular adenoma. Using an image analysis system, two morphometric variables, nuclear area and major axis length of the nucleus, were measured for each case. RESULTS: For both nuclear morphometric variables, statistical differences were found between carcinomas and hyperplastic nodules as well as between carcinomas and adenomas. No statistical differences were found between the nuclear variables in either hyperplastic nodules or adenomas. CONCLUSION: The results confirm the aim of our study, to establish nuclear morphometry by computerized image analysis as an additional tool in the differential diagnosis of thyroid follicular lesions cytologically diagnosed on FNA smears.     

Fine needle aspiration of benign and malignant breast masses associated with pregnancy.

Of 1,612 fine needle aspirates (FNA) of breast lesions performed over a seven-year period, 25 cases (1.5%) were identified as breast masses associated with pregnancy. Patients ranged in age from 16 to 46 years, with a mean of 27. Gestational age at the time of FNA ranged from three months to three months postpartum or following breast-feeding. Cytologic diagnoses of these pregnancy-associated breast masses were: galactocele (5 cases, 20%), lactating adenoma (9 cases, 36%), fibroadenoma with lactational change (7 cases, 28%), juvenile fibroadenoma with lactational change (1 case, 4%), atypical reactive duct cells with lactational change (1 case, 4%) and infiltrating duct carcinoma (2 cases, 8%). The degree of lactational change varied proportionately with gestational age. None of the 22 patients with benign cytologic diagnoses of galactocele, lactating adenoma or fibroadenoma subsequently developed carcinoma. The mean clinical follow-up for these 22 patients was 27 months. Three cases of fibroadenoma and the case of juvenile fibroadenoma were confirmed by surgical excision. Biopsy of the lesion cytologically diagnosed as atypical reactive duct cells with lactational change revealed infiltrating duct carcinoma (IDC). All three patients with IDC had involvement of multiple axillary lymph nodes, and 1 patient had widely metastatic disease. In two cases of IDC the background lactational breast epithelium exhibited marked cytologic atypia that closely resembled the IDC. Pregnancy-related cellular atypia potentially results in a false-positive diagnosis of breast carcinoma on FNA. FNA is useful in distinguishing benign breast masses of pregnancy from those with marked cytologic atypia requiring surgical biopsy and may minimize the delayed diagnosis of carcinoma associated with pregnancy.     

Grading of ductal breast carcinoma by cytomorphology and image morphometry with histologic correlation

OBJECTIVE: To investigate the relevance of image analysis for grading breast carcinoma. STUDY DESIGN: Twenty-five ductal breast carcinoma cases were chosen randomly from routine fine needle aspiration clinics. The results of cytomorphologic grading and image morphometry were correlated with those of histologic grading. The five image morphometric parameters studied were nuclear diameter, nuclear area, nuclear roundness, nuclear perimeter and grey level to compare with chromatin texture. RESULTS: Cytologic grading alone had a high correlation with histologic grading. The lowest correlation was found in grade 2 tumors. When cytologic grading was supplemented with image morphometric parameters, the correlation was higher than that of cytologic grading alone. CONCLUSION: Cytologic grading has a high correlation with histologic grading. The correlation improves further on supplementation with image morphometric parameters.     

The role of morphometry in the cytology of well-differentiated hepatocarcinoma and cirrhosis with atypia

A morphometric study was performed on 200 nuclei per case in six well-differentiated hepatocarcinomas and in six cirrhoses with cytologic atypia, using samples obtained by fine needle aspiration (FNA) biopsy of the liver. The parameters measured were the nuclear area, the nuclear perimeter and the maximum nuclear diameter. The nuclei of well-differentiated hepatocarcinomas could be distinguished from those of cirrhoses on the basis of the larger size and greater anisonucleosis of the former. A statistical analysis (using a two-sided t-test) of the means of the parameters showed significant differences between the two diagnostic groups. These results suggest that morphometric analysis can help in the differential diagnosis between well-differentiated hepatocellular carcinoma and cirrhosis with cytologic atypia in FNA biopsy samples.     

Nuclear image morphometry and cytologic grade of breast carcinoma

OBJECTIVE: To correlate visual cytologic grade with automated nuclear morphometry of carcinoma of the breast. STUDY DESIGN: We randomly selected 24 histologically proven infiltrating ductal carcinomas of the breast and 10 benign breast lesions (fibroadenoma). Hematoxylin-eosin-stained fine needle aspiration cytology (FNAC) smears were selected for both cytologic grade and automated image morphometry. The same hematoxylin-eosin-stained FNAC smears were studied for area, convex area, standard deviation of nuclear area, diameter, perimeter and convex perimeters of nucleus. At least 100 cells from each case were measured with an image cytometer. RESULTS: Mean nuclear area, standard deviation of nuclear area, nuclear diameter, convex area, convex perimeter and perimeter were significantly increased from benign versus grade 1 carcinomas and grade 1 versus grade 2 and 3 carcinomas (one way ANOVA test). However, there was no significant difference in grade 2 versus grade 3 carcinomas. CONCLUSION: Automated image cytometry rapidly and successfully measures various nuclear parameters. The measurement of various nuclear parameters would be helpful in future applications of automated diagnosis and grading of breast carcinomas from cytologic material.     

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.     

Benign mucocele-like lesion of the breast: how to differentiate from mucinous carcinoma before surgery.

The aim of the study was to improve the pre-operative diagnosis of mammary mucinous lesions. All mucinous lesions detected by fine needle aspiration (FNA) and confirmed by histological examination were reviewed by cytological findings, mammographic appearances and sonographic findings. Twenty aspirates had corresponding pathology, including 12 mucinous carcinomas, two mucocele-like lesions (MLL) with atypical ductal hyperplasia, three MLL with ductal hyperplasia and three simple MLL. Simple MLL and mucocele-like with ductal hyperplasia showed scant cellularity, no or rare intact single tumour cells, monolayered arrangement and absence of nuclear atypia. In contrast, most mucinous carcinomas showed higher cellularity, more single tumour cells, three-dimensional clusters, and mild to marked nuclear atypia. However, MLL with atypical ductal hyperplasia showed cytological features overlapping with mucinous carcinoma. MLL had a non-specific mammographic appearance and showed a cystic lesion on sonography. Mucinous carcinoma appeared as a solid mass on sonography and as a distinct nodule on mammography. Based on the combination of FNA cytology and image findings, benign MLL can be correctly distinguished from mucinous carcinoma before surgery.     

The role of micronucleus scoring in fine needle aspirates of ductal carcinoma of the breast

S. Samanta, P. Dey and R. Nijhawan The role of micronucleus scoring in fine needle aspirates of ductal carcinoma of the breast Aims and objectives: Micronucleus (MN) scoring was carried out in benign (fibroadenoma) and malignant (infiltrating ductal carcinoma) breast lesions to evaluate the role of MN as a biomarker in breast carcinomas. We also compared MN scores among different cytological grades of breast carcinoma. Materials and methods: A total of 31 archival cases of fibroadenoma (FA) and 40 cases of infiltrating ductal carcinoma (IDC) were selected. The best May‐Grünwald–Giemsa (MGG) stained fine needle aspiration cytology (FNAC) smear of each case was selected. The MN scoring was carried out independently by two observers on 1000 epithelial cells in oil immersion magnification (100× objective). The MN scores in FA and IDC were compared. The IDC cases were graded and the MN scores in different cytological grades of IDC were compared. Results: The mean MN scores (± standard deviation) in FA and IDC were 0.6 (± 1.1) and 13.6 (± 12.8), respectively, which were significantly different (P < 0.0001). There were seven grade 1, 13 grade 2, and 20 grade 3 IDCs. The mean MN scores (± standard deviation) of grade 1, 2 and 3 IDC were 4.3 (± 2.3), 11.95 (± 9.2) and 21.1 (± 16.7), respectively. An analysis of variance (anova ) test showed a significant difference in MN score between all the grades of IDC (P < 0.05). However, there was no significant difference between fibroadenoma and grade 1 IDC. The Pearson’s correlation coefficient showed positive correlations between MN scoring in the different grades of IDC. Conclusions: MN scoring on routinely stained smears of IDCs was significantly higher than in fibroadenoma and was relatively easy, reliable and reproducible. As MN scoring of grade 1 IDC was similar to fibroadenoma, a larger study should be conducted to compare grade 1 IDC with other benign breast lesions.     

Cytologic findings of breast ductal lavage and concurrent fine needle aspiration in pleomorphic lobular carcinoma in situ: a case report

BACKGROUND: Breast ductal lavage (DL) is a noninvasive procedure for sampling ductal epithelial cells. Patients at risk for breast cancer or with prior history can be monitored by DL. This report compares cytomorphology in concurrent DL, fine needle aspiration (FNA) and histology in a case of pleomorphic lobular carcinoma in situ (PLCIS) with signet ring features. CASE: A 57-year-old woman had DL and FNA performed after quadrantectomy for lobular carcinoma in situ with signet ring cell features. DL and FNA were diagnosed as suspicious and positive for malignancy, respectively. Subsequent biopsy showed PLCIS. Cytomorphologic features of DL, FNA and histology were compared. DL showed epithelial cells in small clusters or single-file arrangement and single-lying; in FNA, single cells predominated. DL and FNA showed nuclear atypia and cytoplasmic vacuoles, the latter more prevalent in FNA. Both samples showed cells with signet ring features. The atypical epithelial cells present in DL and FNA were identical to those seen in the histologic material. CONCLUSION: Cytomorphologic findings in DL, although less striking, are comparable to those seen in FNA. Architecture, nuclear atypia and intracytoplasmic vacuoles are helpful features in DL for establishing a diagnosis of suspicious if not positive for malignancy in LCIS.     

Computerized morphometric image analysis of cytologic nuclear parameters in breast cancer

The value of nuclear morphometry in the preoperative fine needle aspiration (FNA) cytologic diagnosis of mammary lesions was investigated and correlated with the lymph node status of the patients. The subjects consisted of four groups of patients: 49 with invasive ductal carcinomas (18 with no positive nodes, 16 with one to three positive nodes and 15 with four or more positive nodes) and 14 patients with benign lesions. The FNA specimens were smeared onto slides and stained by the May-Grünwald-Giemsa technique. The area, perimeter and maximum diameter of 100 randomly chosen nuclei were both measured with the IBAS image analysis system and semiquantitatively estimated with an eyepiece micrometer. For all three parameters, significant differences were found between benign and malignant lesions. The mean nuclear perimeter allowed the morphometric discrimination between all four groups with statistical significance; nuclear area and maximum diameter did not discriminate patients with invasive carcinoma and one to three positive nodes from those with no positive nodes or more than three positive nodes. Morphometry proved to be far superior to eyepiece measurements with respect to accuracy and reproducibility of the results. The results suggest that nuclear perimeter can be used as an additional parameter not only for the FNA cytologic diagnosis of breast cancer, but also for the estimation of patients' prognosis.     

Fine needle aspiration of breast lesions in women aged 30 and under

Fine needle aspiration (FNA) biopsies of 1,598 breast masses were performed between 1983 and 1989, and of them, 48 were from women aged 30 and under for whom a cytologic diagnosis was made by FNA and histologic follow-up was available. In 37 (77%) of the cases, both the cytologic and histologic diagnoses were benign. Fibroadenoma (20/37) and fibrocystic changes (14/37) were the most common benign lesions aspirated. Eight (17%) FNAs showed cytologic atypia. Four of these atypical lesions proved to be benign (two fibroadenomas, two fibrocystic changes). Epithelial proliferation in fibroadenomas and fibrocystic changes and cellular stroma in a fibroadenoma mimicking phylloides tumor were the causes of atypia in these biopsies. Four of the eight atypical lesions were shown to be carcinoma at biopsy (three infiltrating duct, one atypical medullary). Low cellularity, epithelial cohesiveness mimicking a fibroadenoma and background lactational changes in a pregnant patient were the causes of the atypical, rather than unequivocally malignant, diagnoses in these cases. In three patients (6%), a diagnosis of carcinoma was made by FNA and confirmed histologically (all were infiltrating duct carcinoma). Although most breast masses in women aged 30 and under are benign, cytologic atypia in a breast fine needle aspirate in this age group warrants a surgical biopsy. Clinical follow-up alone may be appropriate for young women with clinically nonsuspicious breast masses without cytologic atypia.     

Apoptosis in breast cancer

OBJECTIVE: To evaluate apoptotic rates on fine needle aspiration (FNA) samples of infiltrating duct carcinoma of the breast and to determine whether cytologic grading improved with consideration of the apoptotic rate in comparison with histologic grading. STUDY DESIGN: We studied 35 women who underwent mastectomy following an FNA diagnosis of infiltrating ductal carcinoma. Concordance between cytologic and histologic grades was calculated. Next, cytologic grades were considered with the apoptotic rates and compared with the histologic grades. RESULTS: An overall concordance of 82.9% was noted between the cytologic and histologic grading systems, with maximum concordance in grade 1 and minimum in grade 3 breast cancers. A highly significant difference in the apoptotic rates, as calculated on cytology, existed between the three histologic grades, indicating a significant increase in apoptosis with rising histologic grade. Applying multiple regression analysis, a significant improvement of cytologic grade with consideration of the apoptotic rate was observed. CONCLUSION: Employing histologic grade as the yardstick, cytology was less sensitive for the purpose of grading breast ductal carcinoma. However, by considering the apoptotic rates, the sensitivity of cytologic grading significantly rose in relation to histologic grade. Larger studies are required to determine whether apoptosis can be incorporated into the existing cytologic grading systems to increase their sensitivity.     

Fibromatosislike metaplastic carcinoma of the breast as a diagnostic pitfall for fine needle aspiration cytology: a case report

BACKGROUND Metaplastic carcinomas of the breast are uncommon, and most display marked cellular atypia. Recently, a low grade fibromatosis-like metaplastic carcinoma was found and displayed little nuclear atypia. CASE A 74-year-old woman presented with a 2.5-cm, palpable breast nodule. Mammogram was reported as suspicious for malignancy. Cytologic examination revealed smears of low cellularity with most cells lying in clusters and having a round or oval shape. Rare cells had a "spindle" shape. Nuclear features were low grade. Rare individual cells had retained cytoplasm. Lumpectomy revealed a fibromatosis-like metaplastic carcinoma. CONCLUSION: Cytologically, fibromatosis-like metaplastic carcinomas are low grade lesions producing smears of relatively low cellularity. Separation from ductal carcinomas is necessary because fibromatosis-like metaplastic carcinomas rarely metastasize to lymph nodes.     

Immunohistochemical studies with monoclonal antibodies B72.3 and MA5 on histologic and cytologic specimens from benign and malignant breast lesions

Monoclonal antibodies B72.3 and MA5 were tested by the avidin-biotin immunoperoxidase method in histologic sections of 38 benign, 22 precancerous and 22 cancerous breast lesions, as well as in fine needle aspiration (FNA) smears and cell blocks of 25 breast carcinomas. Neither B72.3 nor MA5 was specific for breast cancer cells: both also reacted with cells from benign and precancerous conditions. B72.3 as a "detector" of malignant cells or their precursors was superior to MA5, however: it was not reactive to cells in most benign breast lesions (mammary duct ectasia, fibroadenoma and ductal hyperplasia, with and without atypia). Cancerous cells had heterogeneous immunostaining with B72.3, which may lead to false-negative results in relatively hypocellular FNA samples. FNA samples prepared as both smears and cell blocks provided the most abundant cellular samples and the lowest false-negative immunostaining reaction of cancerous cells with B72.3.     

Fine needle aspiration cytology of radiation-induced changes in nonneoplastic breast lesions. Possible pitfalls in cytodiagnosis

The range of radiation-induced changes in fine needle aspiration (FNA) smears of the breast is described. In 41 of more than 800 patients who underwent breast-conserving treatment, a palpable breast lesion developed, and FNA was performed. In six cases, a recurrent carcinoma was present. In the remaining cases, three patterns of nonneoplastic lesions could be discerned: epithelial atypia (14 cases), fat necrosis (10 cases) and poorly cellular smears without epithelial atypia or fat necrosis (13 cases). It is important to be familiar with the patterns of radiation-induced epithelial atypia, since such atypia may lead to a misdiagnosis of recurrent carcinoma. These atypical cells may show impressive anisocytosis and anisonucleosis; however, the nuclear/cytoplasmic ratio remains normal and an admixture of bipolar cells is present. Cell dissociation and necrotic cell debris, as often seen in breast cancer smears, were never encountered in FNA smears from radiated nonneoplastic breasts.     

Applicability of Preoperative Nuclear Morphometry to Evaluating Risk for Cervical Lymph Node Metastasis in Oral Squamous Cell Carcinoma

Background

We previously reported the utility of preoperative nuclear morphometry for evaluating risk for cervical lymph node metastases in tongue squamous cell carcinoma. The risk for lymph node metastasis in oral squamous cell carcinoma, however, is known to differ depending on the anatomical site of the primary tumor, such as the tongue, gingiva, mouth floor, and buccal mucosa. In this study, we evaluated the applicability of this morphometric technique to evaluating the risk for cervical lymph node metastasis in oral squamous cell carcinoma.

Methods

A digital image system was used to measure the mean nuclear area, mean nuclear perimeter, nuclear circular rate, ratio of nuclear length to width (aspect ratio), and nuclear area coefficient of variation (NACV). Relationships between these parameters and nodal status were evaluated by t-test and logistic regression analysis.

Results

Eighty-eight cases of squamous cell carcinoma (52 of the tongue, 25 of the gingiva, 4 of the buccal mucosa, and 7 of the mouth floor) were included: 46 with positive node classification and 42 with negative node classification. Nuclear area and perimeter were significantly larger in node-positive cases than in node-negative cases; however, there were no significant differences in circular rate, aspect ratio, or NACV. We derived two risk models based on the results of multivariate analysis: Model 1, which identified age and mean nuclear area and Model 2, which identified age and mean nuclear perimeter. It should be noted that primary tumor site was not associated the pN-positive status. There were no significant differences in pathological nodal status by aspect ratio, NACV, or primary tumor site.

Conclusion

Our method of preoperative nuclear morphometry may contribute valuable information to evaluations of the risk for lymph node metastasis in oral squamous cell carcinoma.     

Morphometric image analysis of follicular lesions of the thyroid

OBJECTIVE: To determine the role of image morphometry in distinguishing various follicular lesions of the thyroid in cytologic smears. STUDY DESIGN: Archival fine needle aspiration smears of 10 cases each of follicular hyperplasia, follicular adenoma, follicular carcinoma and follicular variant of papillary carcinoma were used for the study. All cases were histopathologically proven. At least 100 random nuclei from each case were subjected to analysis with an image cytometer. Area, convex area, length, width, perimeter, convex perimeter and roundness of nuclei were measured using a 40 x objective (1 pixel = 0.446 micron). RESULTS: ANOVA showed that all the nuclear variables studied were significantly different (P < .05) in follicular hyperplasia as compared to follicular carcinoma and papillary carcinoma. All nuclear variables except roundness were also significantly different (P < .05) between follicular hyperplasia and follicular adenoma. However, between follicular adenoma, follicular carcinoma and papillary carcinoma there was considerable overlap of nuclear morphometric parameters. CONCLUSION: Image morphometry may help to distinguish nonneoplastic follicular lesions (hyperplasia) from neoplastic lesions (adenomas and carcinomas). However, to distinguish benign from malignant follicular lesions, image morphometry might not improve the accuracy of standard cytologic examination.     

Fine needle aspiration cytology of a metastatic duct carcinoma of the prostate: a case report

BACKGROUND: Prostatic ductal carcinoma (PDC) is a rare variant of prostatic adenocarcinoma. Without proper clinical information, a fine needle aspiration (FNA) diagnosis of metastatic PDC can be challenging as this tumor can morphologically mimic adenocarcinomas from other sites. To our knowledge, FNA findings of metastatic PDC have not been previously reported. CASE: An 85-year-old man presented with a large, destructive pelvic bone lesion with soft tissue extension. He had undergone a prostatectomy 30 years earlier for "benign prostatic hypertrophy" but had no known history of malignancy. The aspirates were hypercellular and composed of numerous monolayered or folded cohesive sheets of tumor cells with minimal cytologic atypia. The tumor cells had abundant, clear cytoplasm, evenly spaced nuclei, finely granular chromatin, inconspicuous nucleoli and occasional mitotic figures. The background was clean and contained a few wisps of thin mucin. Cell block sections revealed tumor cells forming tubulopapillary architecture lined with tall columnar cells with focal nuclear pseudostratification, reminiscent of uterine endometrial carcinoma. Positive immunoreactivity for prostate-specific antigen and prostatic acid phosphatase confirmed the tumor's prostatic origin. CONCLUSION: Because of the rarity and nonspecific cytomorphologic characteristics of this tumor, clinical history, radiologic findings and a high index of suspicion in conjunction with ancillary studies are important in achieving a correct FNA diagnosis of metastatic PDC.