Are epithelial cells in fat or connective tissue a reliable indicator of tumor invasion in fine-needle aspiration of the breast?

The diagnosis of breast carcinoma tumor invasion by fine-needle aspiration (FNA) cytology continues to be controversial. To assess the reliability of predicting tumor invasion by FNA, we examined the cytologic smears of 183 FNAs of benign and malignant solid epithelial lesions of the breast for which histologic follow-up was available. The study group consisted of 94 invasive carcinomas, eight pure ductal carcinomas in situ (DCIS), and 81 benign lesions (fibroadenoma, fibrocystic changes, papilloma, adenosis). Epithelial cellularity, presence of epithelial cells in dispersed fat droplets and presence of epithelium within intact fragments of fibrofatty connective tissue were tabulated. Epithelial cellularity in dispersed fat was semiquantitatively scored. The cytologic diagnosis of the epithelial cells in all cases was recorded as benign, malignant, or indeterminant for malignancy. Findings showed that 95.5% of invasive carcinomas, 100% of DCIS, and 68.1% of benign lesions contained epithelial cells in dispersed fat; 80.8% of invasive carcinomas, 66.7% of DCIS, and 60.7% of benign lesions contained epithelial cells in intact fibrofatty connective tissue. Corrected score of epithelium within fat was 0.781 for invasive carcinoma, 0.727 for DCIS, and 0.562 for benign lesions. The difference in values for all parameters was not statistically significant between invasive carcinoma and DCIS, but reached significance between invasive carcinoma and benign lesions. Eighteen cases (7/94 invasive carcinoma, 5/8 DCIS, 6/81 benign lesions) contained atypical epithelial cells indeterminant for malignancy, all of which had epithelial cells present in dispersed fat when dispersed fat was present on the slides, indicating that this criterion was not helpful in discriminating between a benign and malignant diagnosis. We conclude that the presence of epithelial cells either admixed within dispersed fatty droplets or seemingly within fragments of fibrofatty connective tissue is not a reliable indicator of tumor invasion in FNA of the breast, and is frequently found in both benign and malignant breast lesions. The presence of epithelial cells in intact or dispersed fat is most likely a mechanical artifact of aspiration and/or smear preparation. Diagn. Cytopathol. 16:137–142, 1997. © 1997 Wiley-Liss, Inc.     

Cell blocks of breast FNAs frequently allow diagnosis of invasion or histological classification of proliferative changes

Two major limitations of breast fine needle aspiration (FNA) compared with core needle biopsies (CNB) are the inability to determine whether a cancer is invasive and to classify proliferative lesions. We studied 40 consecutive "rapid cell blocks" from breast FNAs with surgical pathology follow-up to test whether cell blocks can overcome these limitations. Of 25 carcinomas, invasion could be identified in the cell block sections in 11 (44%). One cystosarcoma phyllodes was suspected based on the cell block sections. Cell blocks from 12 of 14 benign breast FNAs showed sufficient cells to assign a histologic diagnosis of no hyperplasia (1 case, confirmed on follow-up) and usual hyperplasia (11 cases; confirmed in eight of 11 on follow-up). Specific histologic diagnoses included intraductal papilloma (2 cases), and in situ lobular neoplasia (2 cases). Cell blocks complement smears and monolayers and appear to overcome major limitations of breast FNA.     

Tubular carcinoma of the breast: Cytologic features in fine-needle aspirations and application of monoclonal anti-α-smooth muscle actin in diagnosis

Twenty fine-needle aspirations (FNAs) of histologically proven tubular carcinoma of the breast (TCB) were reviewed, and the staining distribution of α-smooth muscle actin (SMA) was evaluated to see if this improved FNA sensitivity. In 18 cases, the aspirates were cellular, consisting predominantly of epithelial cells arranged in cohesive tubular structures that appeared angular or twisted. Single epithelial cells were present in varying numbers in 14 cases (70%). Cribriform fragments corresponding to in situ ductal carcinoma were noted in 9 cases (45%). Individual, bare nuclei were present in seven cases (35%). The initial cytologic diagnoses were 10 carcinomas, eight suspicious for carcinoma, and two cases were misinterpreted as fibroadenoma. In 8 of 14 cases, the epithelial fragments stained negatively for SMA, whereas in six cases some fragments (<10%) stained positively. These findings were in contrast to a reticulated staining pattern noted in almost all of the epithelial fragments in nine fibroadenomas and three fibrocystic changes. Eighteen well-differentiated invasive ductal carcinomas stained negatively, whereas four had occasional positively staining fragments. We conclude that TCB displays distinct cytomorphologic features that can be recognized or at least suggested by FNA. Awareness of the cytologic characteristics—angulated tubular structures with or without single epithelial cells—coupled with mammographic/ultrasound findings, is necessary to avoid a misdiagnosis. Alpha-smooth muscle actin staining may help in selected cases. © 1994 Wiley-Liss, Inc.     

A retrospective study of the diagnostic accuracy of fine-needle aspiration for breast lesions and implications for future use

In recent years, the use of fine-needle aspiration (FNA) in the diagnosis of breast lesions has declined in many institutions. We sought to evaluate the role of FNA for breast lesions and the annual rate of the procedure at our institution over a 4(1/2) year period (May 2002-October 2006). A total of 831 FNAs were performed, with 258 (31%) having histologic follow-up. The number of FNAs obtained was 159 from 5/02 to 4/03, 192 from 5/03 to 4/04, 194 from 5/04 to 4/05, 191 from 5/05 to 4/06, and 95 from 5/06 to 10/06. Each case was placed into one of four categories: nondiagnostic (9%), benign (77.5%), atypical/suspicious (5.5%), or malignant (8%). Surgical tissue was available for 37% of nondiagnostic cases, 22% of benign cases, 80% of atypical/suspicious cases, and 72% of malignant cases. The overall sensitivity and specificity for FNA was 83 and 92% respectively. The overall positive and negative predictive values were 83 and 92% respectively. There were no false-positive cases, indicating a positive predictive value of 100% for a Dx of malignancy. For cases with surgical follow-up, the false-negative rate was 5.4%. Although there is a national trend away from FNAs of breast lesion, this has not been the experience at our institution. Although FNA may not be ideal in the initial evaluation of suspicious lesions, we argue that FNA for clinically benign palpable lesions and recurrent carcinomas has significant value.     

Ultrasound-guided fine-needle aspiration biopsy remains a valid approach in the evaluation of nonpalpable breast lesions

The use of ultrasound-guided fine-needle aspiration (FNA) biopsy for nonpalpable breast lesions varies considerably. This retrospective study stresses the role of breast FNA in evaluating sonographically suspicious nonpalpable breast masses using a probabilistic reporting system. One hundred and eight consecutive ultrasound-guided FNA biopsies diagnosed as positive (32), suspicious (8), atypical (11), benign (55), and unsatisfactory (2) were analyzed and correlated with 61 subsequent surgical specimens. All positive cytologies showed carcinoma on histology; suspicious cases were followed by 5 carcinomas, 2 fibroadenomas, and 1 papillary lesion. Follow-up of atypical cases included 4 carcinomas, 3 fibroadenomas, and 2 papillary lesions, while all 10 biopsies following benign cytology showed fibrocystic changes. Two cases with suspicious sonographic findings but unsatisfactory cytology had lobular carcinoma. The remainder of the benign and atypical cases were followed clinically and radiographically for at least 10 months and had no evidence of carcinoma. Positive predictive values were positive, 100%; suspicious, 63%; atypical, 36%; benign, 0%. Most (40/43; 93%) carcinomas were invasive. In conclusion, ultrasound-guided FNA for nonpalpable breast lesions is highly accurate, and probabilistic reporting helps direct patient management.     

Fine-needle aspiration cytology of metastatic neoplasms in the breast

Twenty cases of metastatic neoplasms in the breast were identified in a series of 1,034 fine-needle aspirations (FNAs) of the breast, of which 389 were malignant. Patients with breast carcinomas in whom metastasis to the contralateral breast developed were excluded from this study. This series consisted of 17 women and 3 men, ranging in age from 28 to 63 years (mean, 49 years). The tumors included oat cell carcinoma (three), melanoma (three), ovarian serous carcinoma (one), bronchogenic adenocarcinoma and squamous carcinoma (four and two, respectively), lymphoma (two), carcinoid (two), transitional cell carcinoma (one), plasma cell myeloma (one), and rhabdomyosarcoma (one). In two patients, the breast mass was the first manifestation of an extramammary cancer (two adenocarcinoma of the lung). Eleven patients died of disseminated cancer shortly after the breast metastasis was diagnosed. In most cases, the aspirates displayed the cytologic features characteristic of the primary tumors, thereby establishing the metastatic nature of the neoplasm. In four cases (two carcinoids, one myeloma, and one rhabdomyosarcoma), the cytologic features were difficult to differentiate from a primary breast carcinoma; however, the final diagnosis was established by electron microscopic examination and immunocytochemical studies on the aspirates. One case (adenocarcinoma of the lung) was misdiagnosed as primary breast carcinoma on both FNA and mastectomy specimen. Because metastatic neoplasms in the breast may mimic primary breast tumors, the authors recommend the following: (1) Evaluation of FNA of breast should be done with complete knowledge of the patient's clinical history. (2) The possibility of metastasis should be suspected in lesions with unusual cytologic patterns. (3) Ancillary studies on FNA can be helpful in interpreting selected cases.     

Nuclear grading and flow cytometric DNA pattern in fine-needle aspirates of primary breast cancer

Fine-needle aspiration (FNA) biopsy is increasingly used in the diagnosis and biological characterization of breast carcinomas in patients who receive preoperative chemotherapy. In this context, nuclear cytologic grade supplemented by DNA content could play an important role in the morphologic assessment of breast cancer. In this study, DNA ploidy pattern, analyzed by flow cytometry on FNAs from 92 primary breast carcinomas, was related to cytologic nuclear grade. Twenty-seven samples were cytologic grade 1, 33 were grade 2, and 32 were grade 3. Ploidy correlated with cytologic nuclear grade (P = 0.0001). Thirty percent of grade 1, 55% of grade 2, and 84% of grade 3 tumors were DNA aneuploid. For 30 of the 92 FNAs, it was possible to compare nuclear cytologic grade with the corresponding histologic grade using the Scarff, Bloom, and Richardson system. A high concordance (80%) between nuclear grade on FNAs and histologic grade was found. DNA flow cytometry in combination with nuclear cytologic grade might represent additional information for the characterization of breast cancer diagnosed by FNA. Diagn Cytopathol 1996;15:116–120. © 1996 Wiley-Liss, Inc.     

Lobular breast carcinoma metastasis to skeletal muscle,two case reports diagnosed by ultrasound guided FNA with evaluation of the roles of interventional cytopathology

Skeletal muscle metastasis from breast carcinoma is a relatively rare clinical entity. We report two cases of breast cancer metastatic to the skeletal muscle, diagnosed by ultrasound guided fine needle aspiration (US‐FNA) biopsy done by interventional cytopathologists at an outpatient cytopathology center. Our two patients presented with lower anterior neck firmness and chest wall mass, respectively. Ultrasound evaluation of our first case demonstrated hypo‐echoic thickened anterior strap muscles while in the second case there was significant distortion of the anatomy from previous surgeries. It was necessary to proceed with FNA biopsy even when their ultrasound findings were equivocal, to establish a definite rapid diagnosis. The immediate onsite evaluation findings were suggestive of malignancy in both cases with subsequent core biopsy confirming the diagnosis of metastatic breast carcinoma. In cytopathology, point‐of‐care (POC) ultrasound is used as an adjunct tool that offers visual guidance during FNA of nonpalpable masses and enables sampling of lesional “hot” spots to ensure specimen adequacy. Studies have demonstrated a reduction in FNA nondiagnostic rates with the use of ultrasound‐guidance consequently reducing health care costs associated with nondiagnostic FNAs. US‐FNA also provides adequate samples for cell block preparations. Metastatic lobular carcinoma of the breast has a wide range of clinical presentations and a high level of suspicion is advised. Cytopathologists‐performed US‐FNA is a proven, less‐invasive, cost‐effective tool that provides timely cytologic diagnosis.     

Fine-needle aspiration of superficial and deeply seated lymph nodes on patients with and without a history of malignancy: review of 439 cases

This study addresses the utility of fine-needle aspiration (FNA) in assessing lymphadenopathy in patients with and without a previous history of malignancy. We reviewed the FNAs of superficial and deeply seated lymph nodes performed at our institution over a period of 18 yr (1983-2001). Where applicable, we also reviewed and report here the results of subsequent surgical excisional biopsies. We analyzed data from 439 patients, who ranged in age from 1 to 90 yr. The neck and retroperitoneum were the most frequently sampled sites (47% and 25%, respectively). Among the 439 FNAs, adequate material was obtained in 421 cases (96%); the remaining 18 were unsatisfactory (4.1%). Malignant diagnoses were rendered in 330 cases (75% of 439), four were suspicious for lymphoma (0.9%), and 87 were read as reactive lymph nodes or granulomas (20%). The most common malignant cytologic diagnoses from these lymph node FNAs were adenocarcinoma, squamous cell carcinoma, and lymphoma. We compared results between two major groups: patients with a history of malignancy and those without. FNA showed malignancy in 87% of patients with a history of cancer and 41% without such a history. Thirty-three or 10% of patients with a history of malignancy were given a benign diagnosis and follow-up surgical excisional biopsies were performed in nine of these cases. Four of the nine showed low-grade lymphoma. Of the 18 non-diagnostic FNAs, nine came from patients with a history of malignancy and in six of these nine who had a follow-up surgical excisional biopsy the lymph nodes were positive for malignancy. Of the other nine, who had no history of malignancy, only two had follow-up biopsies and both of these were negative. Patients with a history of malignancy are more than twice as likely to show malignancy on lymph node FNA compared to those without such a history (87% vs. 41%). Knowing whether a patient has a history of malignancy provides the appropriate level of suspicion for ordering ancillary investigations or even recommending excisional biopsy for further evaluation.     

Utilization of fine-needle aspiration in the diagnosis of metastatic tumors to the kidney.

Renal masses secondary to metastases are not common. Few comprehensive reviews exist, which consist primarily of autopsy and radiologic reports. The purpose of this study was to review the types and incidences of various neoplasms which metastasize to the kidney and to determine the usefulness of fine-needle aspiration (FNA) in diagnosing them. Two hundred and sixty-one radiologically guided FNAs of renal lesions over a 9-yr period were reviewed. The diagnoses of the 261 renal FNAs were as follows: 136 (52%) were malignant, 111 (43%) were benign, and 14 (5%) were unsatisfactory. Of the 136 positive FNAs, 28 (21%) revealed metastatic tumors. The overall incidence of renal FNAs displaying metastatic tumors was 11%. Among the 28 patients with metastases to the kidney, 23 patients were men and 5 were women, with the mean age being 58 yr. Twenty-five patients (89%) had prior history of a primary malignancy, including lung carcinoma (11 cases, 39%), lymphoma (8 cases, 29%), hepatocellular carcinoma (3 cases, 11%), and one case each of breast, pancreatic, and cervical cancer. In the remaining 3 patients (11%), with metastatic adenocarcinoma (2 cases) and squamous-cell carcinoma (1 case), the primary tumor site remained unknown despite an extensive clinical workup. Overall survival after FNA was poor, with a mean of 9.8 mo. FNA is useful in the diagnosis of masses in the kidney secondary to metastatic disease. This information is of clinical importance, principally in the exclusion of a primary malignancy, but also to avoid unnecessary surgery and to plan for subsequent patient care.     

Intratumoral DNA content variability. A study of non-small cell lung cancer.

Twenty-eight resected primary non-small cell lung carcinomas were studied for intratumoral DNA variability by flow cytometry (FCM). Three separate tissue specimens from each resected tumor were divided equally for FCM analysis and histologic evaluation. FCM analysis also was performed on fine-needle aspirates (FNAs) from the center of the resected tumor. Histologically, there were 8 squamous carcinomas, 19 adenocarcinomas, and 1 large cell carcinoma. Twenty-three tumors (82%) were aneuploid, and 5 (18%) were diploid. The DNA index in aneuploid neoplasms ranged from 0.91 to 3.30 (mean, 1.64). All 5 diploid and 19 (83%) of the (23) aneuploid neoplasms manifested intratumoral DNA stability. Four (17%) of the aneuploid tumors showed regional DNA heterogeneity expressed as additional stemlines in at least one sample. The FNA yield was sufficient in 21 cases and inadequate for complete analysis in 7 cases. In general, good correlation between FNA and tissue analysis was obtained. However, in three of the aneuploid neoplasms, FNA materials did not reveal an additional nondominant stemline, as noted in the tissue specimens. The authors attribute this finding to a dilutional factor in the aspiration material. The authors conclude that most non-small cell lung carcinomas express DNA stability; FNA provides adequate cellular material for FCM in most cases.     

Fine-needle aspiration of breast carcinomas with prominent lymphocytic infiltrate

Carcinomas of the breast with prominent lymphoplasmacytic background are commonly encountered in cytology. The aim of this study was to assess the prevalence of different types of carcinomas that share this common feature, identify possible distinguishing cytologic features, and evaluate the diagnostic pitfalls in this group of tumors. Eighteen fine-needle aspirations (FNAs) of breast carcinomas with heavy lymphoplasmacytic background were reviewed. Histologic follow-up was reviewed in all cases. Of 18 cases, there were 9 invasive ductal carcinomas (IDC), and 9 medullary carcinomas (6 typical and 3 atypical). FNAs from typical medullary carcinomas (TMC) showed more severe nuclear atypia and macronucleoli than the cases of IDC and atypical medullary carcinomas (AMC). Gland formation was absent in the TMC but was common in IDC and AMC. No cytologic differences were noted between IDC and AMC. Nucleoli were larger in TMC (mean 4, microm) than in AMC (mean, 2 microm) and IDC (mean, 1.5 microm). We conclude that lymphocytes and plasma cells may be seen in different types of breast carcinomas and should not be considered a diagnostic feature of TMC. Features potentially helpful in the cytologic differential diagnosis of a carcinoma with prominent lymphoplasmacytic background are nucleolar size (4 microm in MC, vs. 1.5 and 2 microm in IDC and AMC, respectively) and the degree of nuclear atypia. Lymphocytosis may be part of the carcinoma or may originate from a lymph node involved by metastases. In rare cases, a prominent neutrophilic infiltrate may also be present.     

Invasive micropapillary carcinoma of the breast: high incidence of lymph node metastasis with extranodal extension and its immunohistochemical profile compared with invasive ductal carcinoma

AIMS: Invasive micropapillary carcinoma of the breast is an aggressive and distinctive variant of breast cancer. These tumours have a characteristic histological appearance and have been associated with a high incidence of axillary lymph node metastases and a poor clinical outcome. The aims of this study were to investigate the immunohistochemical profile of invasive micropapillary carcinoma of the breast, to compare it with invasive ductal carcinoma, and to identify the morphological parameters which predict its poor outcome. METHODS AND RESULTS: Fifty-three (2.6%) invasive micropapillary carcinomas of the breast from 2022 cases of infiltrating breast carcinomas were identified by retrospective review. The patient age at presentation ranged from 33 to 78 years (mean 52.5 years). The tumour size ranged from 5 to 70 mm (mean 27 mm). Eighty-two percent (43 of 53) were of high histological grade; 69% (33 of 48) of cases with axillary lymph node dissections had positive lymph nodes; and 75.5% (40 of 53) had lymphatic invasion: 46% (22 of 48) of cases had extranodal extension. Of lymph node-positive cases, 61% had four or more metastatic lymph nodes. Of tumours with tumour size >10 mm, 77% had positive lymph nodes. The percentages of cases positive for oestrogen receptor (ER) and progesterone receptor (PR) were 68% and 61%, respectively. These values were significantly higher than the values for invasive ductal carcinomas. p53 and c-erbB-2 were detected in 48% and 54% of cases, respectively. The mean value of Ki67 was 26%. Follow-up was available in 36 patients. Eight patients had local recurrences, nine patients had distant metastases, and 10 patients died of disease within a follow-up period of 9 years. CONCLUSION: Lymphotropism and an unfavourable prognosis are the hallmarks of this distinct entity. Prognostic markers such as ER, PR, p53, and c-erbB-2 failed to provide new criteria to allow discrimination of these tumours from other breast cancers.     

Tubular carcinoma of the breast and associated intra-epithelial lesions: a comparative study with invasive low-grade ductal carcinomas

Ductal intra-epithelial lesions of the breast are associated with invasive neoplasms and comprise a large spectrum of histological patterns. We have examined 23 cases of pure tubular carcinomas (TCs) of the breast and 53 cases of invasive ductal low-grade carcinomas to determine the relationship and distribution of intra-epithelial lesions, mainly of ductal in situ carcinoma type, but including also lobular intra-epithelial neoplasia (LIN) in both entities. Eleven cases of TC showed flat epithelial atypia (FEA) (47.8%), and, in 14 and 6 cases, micropapillary and cribriform low-grade ductal carcinoma in situ (DCIS) were present (60.7 and 26.1%, respectively). On the opposite, in ductal grade I invasive carcinomas, the most frequent architectural pattern was low-grade DCIS growing in arcades in 26 cases (49%). While absent in TCs, low-grade DCIS of solid type was found in five (9.4%) cases of ductal invasive carcinomas, where FEA were present in seven (13.2%) cases. LIN lesions were present in four (17.4%) cases of TC, whereas they represented 7.5%, as reported by Carstens et al. (Am J Clin Pathol 58:231–238, 1972), of cases of low-grade carcinomas. These results suggest that invasive pure TC and low-grade ductal carcinomas of the breast are different lesions, and support the fact that TC, of low histopathological grade, is a particular distinct tumoural entity.     

The significance of the diagnosis of atypia in breast fine-needle aspiration

The diagnosis of atypia in breast fine-needle aspiration (FNA) continues to be an area of debate in cytology practice. The aim of this study was to assess the clinical significance of this term and to evaluate potential morphological criteria, which would determine the patient's outcome. A computer-based search was carried out to retrieve breast FNAs performed between 1990 and 2000 that were diagnosed as atypical. Cases followed by surgical resection were reexamined for the presence of morphological features potentially differentiating benign and malignant lesions. Out of 1,568 breast FNAs, there were 64 cases (4%) with a diagnosis of atypia. Thirty-eight cases had surgical follow-up material that revealed malignancy in 14 cases (37%) and benign lesions in 24 cases (63%). The benign diagnostic categories included fibrocystic change (12/24), fibroadenoma (3/24), tubular adenoma (2/24), and nonspecific findings (7/24). The malignant diagnoses included ductal carcinoma (9/14), lobular carcinoma (3/14), ductal carcinoma in situ (DCIS; 1/14), and tubular carcinoma (1/14). The evaluation of cytological criteria used to differentiate benign from malignant lesions (i.e., cellularity, loss of cohesion, myoepithelial cells, nuclear enlargement, nuclear overlap, prominent nucleoli) revealed significant overlap between benign and malignant cases, particularly in cases of fibroadenoma, tubular adenoma, and proliferative breast disease. The surgical follow-up of four hypocellular cases revealed lobular carcinoma in two cases and ductal carcinoma in the remaining two cases. Our study confirmed that the diagnosis of atypia is clinically significant because it is associated with a high probability of malignancy. No morphological criterion is able to reliably differentiate benign and malignant lesions in cases diagnosed with atypia. Diagnosis of atypia is particularly significant in hypocellular cases. We recommended that breast FNAs with a diagnosis of atypia be evaluated further histologically.     

Patterns of distribution of cytokeratins 20 and 7 in special types of invasive breast carcinoma: a study of 123 cases

Metastatic adenocarcinomas of unknown primary site are a common clinical problem. Invasive ductal carcinomas of the breast and some special types of invasive breast carcinoma are common sources of metastases. Immunohistochemical algorithms, such as a combination of cytokeratins 20 and 7, can be helpful in this situation. Detailed phenotyping of the different types and subtypes of primary invasive carcinomas and their metastases is an essential prerequisite for a successful search for an unknown primary tumor. A series of 123 primary invasive breast adenocarcinomas of special type and of 27 lymph node metastases was analyzed. Sections of selected blocks were stained with two monoclonal cytokeratin antibodies (CK20 and CK7) and evaluated as negative (no staining), focally positive or diffusely positive. Of the 123 carcinomas, 113 (92%) proved to be CK20 negative. Three of 82 (4%) invasive lobular carcinomas, three of 11 (27%) mucinous carcinomas, one of 10 (10%) tubular carcinomas, and one invasive papillary carcinoma stained diffusely with CK20. Additionally, a tubulolobular carcinoma and a medullary carcinoma showed focal CK20 positivity. One hundred twenty (98%) of the 123 tumors were CK7 positive, five of them only focally. One of the four solid invasive lobular carcinomas, one medually carcinoma, and one invasive papillary carcinoma were completely negative for CK7. Only two cases, one mucinous and one invasive papillary carcinoma, exhibited the CK20(+)/CK7(-) ("colorectal") pattern. One of the lymph node metastases was CK20(+); another was CK7(-). Like their ductal counterparts, invasive breast carcinomas of special type are usually CK20(-)/CK7(+); they generally retain this phenotype in their metastases. However, there are CK20-positive special-type breast carcinomas that can be confused with gastrointestinal or pancreaticobiliary carcinoma in metastases, especially if they are mucinous or invasive lobular.     

Oncocytic carcinoma of the breast: frequency, morphology and follow-up

Oncocytic breast carcinomas are tumors composed of no fewer than 70% of oncocytic cells (World Health Organization). The purpose of this study was to determine the frequency, morphologic, immunohistochemical, and clinical features of invasive oncocytic carcinoma in a large series. Twenty-eight cases of putative oncocytic breast carcinoma (selected cases group) and 76 consecutive cases of invasive breast carcinoma (consecutive cases group) were analyzed. Immunohistochemistry for mitochondria, gross cystic disease fluid protein 15, chromogranin, estrogen receptor, progesterone receptor, androgen receptor, HER2/Neu, cytokeratin 7, cytokeratin 14, epithelial membrane antigen, and differentiation cluster 68 was performed. Score for mitochondria was based on intensity and percentage of immunopositive cells. Classes were as follows: (1) oncocytic carcinoma: at least 70%, 3+; (2) mitochondrion-rich carcinoma: 50% to 70%, 3+, or more than 50%, 2+; and (3) all the other cases were referred to as invasive breast carcinoma. Ultrastructural examination was available for 6 cases of oncocytic carcinoma. Morphologic and immunohistochemical features of the 3 groups were compared using Fisher exact test (P < .05). For overall survival analysis, Kaplan-Maier curves were compared using log-rank and Wilcoxon tests (P < .05). Our results suggest that oncocytic breast carcinoma is a morphologic entity with distinctive histologic and ultrastructural features. Mitochondrion-rich carcinomas are histologically similar to oncocytic carcinomas and constitute 19.7% of all invasive carcinomas, indicating that cytoplasmic eosinophilia in breast cancer cells is often due to accumulation of mitochondria. Oncocytic carcinomas and mitochondrion-rich carcinomas are more often grade III tumors and show human epidermal growth factor receptor 2 overexpression. Clinical features and overall survival of oncocytic carcinomas are not distinctive because they are similar to those of the other cases when matched for grade and stage.     

Fine-needle aspiration of the thyroid: rate and causes of cytohistopathologic discordance

Fine-needle aspiration (FNA) of the thyroid gland is a widely utilized, sensitive, specific, and cost-effective method for the evaluation of thyroid nodules. The purpose of this study was to evaluate the accuracy of thyroid FNA and causes of cytohistological discordance in our institution. Six hundred twenty-five thyroid FNAs obtained from 503 females (mean age, 54) and 122 males (mean age, 51) in whom histopathologic follow-up material was available for review, were analyzed. FNAs were classified as: nondiagnostic, negative, intermediate, and positive for malignancy, and the histopathologic material was categorized as benign or malignant. The review revealed 93% sensitivity and 96% specificity for the FNA diagnoses. The FNA results were diagnostic in 87%, indeterminate in 6%, and nondiagnostic in 7% of the cases. Cytohistologic correlation was achieved in 88% of the cases. The false-negative rate was 4% and the false-positive rate was 8%. The most common pitfalls for false-negative diagnoses consisted of suboptimal material and underdiagnosis of papillary carcinoma due to cystic degeneration. The most common pitfall for false-positive cases was overdiagnosis of follicular neoplasms. Our study confirmed that FNA of thyroid nodules can be performed with high sensitivity and specificity by experienced clinicians or pathologists. The application of strict specimen adequacy rules for FNA interpretation is likely to decrease the rate of false-negative and false-positive diagnoses.     

Fine-needle aspiration Is limited in the classification of benign breast diseases

Fine needle aspiration (FNA) has been proven to be accurate for the detection of breast carcinomas. However, its utility in the classification of benign breast lesions is less clear. We therefore undertook a study of 76 adequate preoperative FNAs of the breast from patients whose surgical biopsies of the breast were shown to be benign (18 nonproliferative diseases, 30 fibroadenomas, 19 proliferative breast diseases without atypia, and 9 proliferative breast diseases with atypia). A number of architectural and cellular features on cytology were evaluated. Histology slides were also reviewed. Both cytology and histology specimens were categorized as nonproliferative disease, fibroadenoma, proliferative breast disease without atypia, and proliferative breast disease with atypia. There was exact diagnostic correlation between cytology and histology in only 42 (55%) of the 76 cases. No cellular or architectural features on FNA examined correlated with the presence of epithelial proliferation on histology. The presence of two epithelial cell populations (one unremarkable and one atypical), small but prominent nucleoli, and nuclear pleomorphism on FNA significantly correlated with the presence of atypia on histology. However, these features are also present in breast lesions without proliferation or atypia, and are not diagnostic of atypical proliferative lesions of the breast. Therefore, FNA of the breast is limited in classifying benign breast diseases. Diagn. Cytopathol. 1998;18:56–61. © 1998 Wiley-Liss, Inc.