ultrasonographic findings of metaplastic squamous breast

Metaplastic carcinoma is a rare form of breast carcino-ma that comprises less than 5% of all breast malignan-cies (1, 2). These tumors are ductal carcinomas that canundergo a variety of metaplastic changes including

squamous cell, spindle cell, and heterologous mes-enchymal growth (3, 4). The most common of thesemetaplastic changes is squamous metaplasia, and its in-cidence varies from 0.5 to 2.0% (5). The microscopic cri-teria for the diagnosis of the squamous component aredefined as keratinization, intercellular bridges and cysticareas (3, 4). Although there have been many reportsabout the radiologic findings of metaplastic breast carci-noma, to our knowledge, there have been few reportsabout the ultrasonographic (US) findings of metaplasticsquamous breast carcinoma. Therefore, we describedhere the US appearance of metaplastic squamous breast

J Korean Radiol Soc 2004;51:669-674

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Ultrasonographic Findings of Metaplastic SquamousBreast Carcinoma and the Pathologic Correlation1

Jung Hee Shin, M.D., Asiry Hwang, M.D., Hye-Young Choi, M.D., Sun Hee Sung, M.D.2,YooKyung Kim, M.D., Sun Hwa Lee, M.D.

1Department of Radiology, College of Medicine, Ewha Womans University2Department of Pathology, College of Medicine, Ewha Womans UniversityReceived February 23, 2004 ; Accepted October 12, 2004Address reprint requests to : Jung Hee Shin, M.D., Department ofRadiology, Ewha Womans University Mokdong Hospital, 911-1 Mokdong Yangcheongu Seoul 158-710, Korea.Tel. 82-2-2650-5173 Fax. 82-2-2650-5302 E-mail: [email protected]

Purpose: We investigated the ultrasonographic (US) appearance of metaplastic squa-mous breast carcinoma with the pathologic correlation.Materials and Methods: During an 8-year period, the US appearances of 10 patientswith metaplastic squamous breast carcinoma were retrospectively analyzed on the ba-sis of the Breast Imaging and Reporting Data System (BI-RADS) - US lexicon. These 10patients included 9 patients having invasive adenocarcinomas of the breast with morethan 30% squamous metaplasia, and one patient had pure primary squamous cell car-cinoma. We correlated the US findings with the pathologic findings.Results: On US, the majority of the tumors showed oval shapes (70%), indistinct mar-gins (50%), parallel orientation (80%), echogenic halos (60%), complex echogenicitywith solid and cystic components (60%), and posterior enhancement (70%). The find-ings of calcifications (20%) and metastatic axillary lymph nodes (10%) were rare. Onpathologic examination, half of the tumors showed infiltrative microscopic margins.All six cases showing complex echogenicity with solid and cystic components on USwere pathologically related to the cystic or necrotic portion, and three of these caseshad hemorrhage. Conclusion: On US, metaplastic squamous breast carcinoma mainly manifested asoval, complex, echoic masses with indistinct margins and posterior enhancement thatwas pathologically related to the cystic or necrotic portions.

Index words : Breast neoplasmsUltrasound (US)

carcinoma along with the pathological correlation.

Materials and Methods

Of a total of 665 breast cancers that were treated atour hospital between 1994 and 2002, we collected tencases (1.5%) of metaplastic squamous breast carcinomasby a computer search of the pathology records. We ana-lyzed the clinical, US and pathological findings, and themicroscopic slides were reviewed by a pathologist whowas an expert on breast cancer. All the patients present-ed with a palpable mass and their ages ranged from 32to 62 years, (the mean age was 47).

All the patients underwent preoperative sonography.The sonography was done with linear-array transducers(7 MHz) on XP 10 (Acuson, Mountain View, CA) ultra-sound scanners. According to the American College ofRadiology Breast Imaging Reporting and Data System(BI-RADS)-US lexicon, the sonographic findings were as-sessed retrospectively, focusing on the lesion’s size,shape, orientation, margin, boundary and echo pattern,the presence or absence of posterior enhancement andcalcification, and the status of the axillary lymph nodes(8).

The shape of the lesions was classified into 3 types:oval, round and irregular. The orientation of the lesionswas assessed as to whether the long axis of the lesionwas paralleled or not to the skin line. The margin of thelesions was divided into 3 types: circumscribed, partial-

ly circumscribed and not circumscribed. The non-cir-cumscribed margins were subclassifed into indistinct,angular, microlobulated and spiculated. The lesionboundary was evaluated for an abrupt interface or anechogenic halo. The echo pattern was divided into ane-choic without internal echos, hyperechoic that was de-fined as having increased echogenicity relative to fat orit was equal to the fibroglandular tissue, complex echoicwhich contained both anechoic (cystic) and echogenic(solid) components, and hypoechoic that was definedrelative to fat.

Tumors were considered to be metaplastic squamouscarcinomas if the squamous metaplastic componentconstituted at least 30% of the tumor and it merged intofoci of infiltrative ductal carcinoma not otherwise speci-fied (4). The tumors in which foci of infiltrative ductalcarcinoma were not apparent were considered to be

“primary squamous cell carcinomas”. On pathologic ex-amination, the proportion of squamous metaplasticcomponents, the margin and the intratumoral necroticor cystic portion were assessed. We correlated the USfindings with the pathologic findings.

Results

Clinical Findings

All patients presented with a palpable mass that hadnoticed by the patients for a week to 6 months. Two pa-tients experienced a recent sudden growth of the mass.

Jung Hee Shin, et al: Ultrasonographic Findings of Metaplastic Squamous Breast Carcinoma and the Pathologic Correlation

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Table 1. US Findings (Shape, Margin and Echo Pattern) and the US-Pathologic Correlation of 10 Patients with Metaplastic SquamousBreast Carcinoma

US US Pathology US Pathology

Pt % of S-M Tumor Tumor Size, Shape Margin Echo pattern Cystic necrosis, location cm hemorrhage

001* 100 LOQ 4.0 Oval Indistinct Infiltrative Complex Cystic necrosis,Hemorrhage

02 30 UOQ 2.8 Oval Indistinct Infiltrative Complex Cystic necrosis03 30 UC 2.9 Oval Indistinct Infiltrative Complex Cystic necrosis04 60 UOQ 2.4 Irregular Indistinct Infiltrative Complex Cystic necrosis05 > 70 UOQ 6.8 Oval Partially Pushing, Cystic necrosis

circumscribed Partially infiltrative Complex Hemorrhage06 > 70 UOQ 3.9 Round Partially Cystic necrosis,

circumscribed Pushing Complex Hemorrhage07 50 UOQ 2.2 Round Indistinct Infiltrative Hypoechoic Macro necrosis08 70 OC 5.6 Oval Microlobulated Pushing Hypoechoic Microcystic necrosis

Hemorrhage09 70 LIQ 1.7 Oval Circumscribed Pushing Hypoechoic Micro necrosis10 70 UOQ 3.7 Oval Partially Pushing, Inhomogeneous Micro necrosis

circumscribed Partally infiltrative hypoechoic

Abbreviations : Pt, patient; S-M, squamous metaplasia; UC, upper center; UOQ, upper outer quadrant; LIQ, lower inner quadrant; OC,outer center; LOQ, lower outer quadrant.*, Primary SCC

One patient had pain at the palpable mass on physicalexamination, and five tumors were found in eachbreast, respectively. The tumors were located in the up-per outer quadrant in six cases, and in the upper center,outer center, lower inner quadrant and lower outerquadrant in one case each.

Ultrasonographic Findings

The US findings about the shape, margin and echopattern of the tumors are summarized in Table 1. OnUS, the range of the longest diameter of the masses wasfrom 1.7 cm to 6.8 cm, (the mean diameter was 3.7 cm).The shape of the tumor was oval in seven cases, roundin two cases and irregular in one case. The orientation ofthe mass was parallel in eight cases and nonparallel intwo cases. The tumor margins were circumscribed inone case, partially circumscribed in three cases and notcircumscribed in six cases. The non-circumscribed mar-gins were subclassifed as indistinct margins in 5 cases,and microlobulated in 1 case. The lesion boundaries in-

cluded six cases with echogenic halos and four caseswith abrupt interfaces. Six cases showed complex echo-genecity with solid and cystic components (Fig. 1), threecases showed homogeneous hypoechogenicity, and theremaining one case showed inhomogeneous hypoe-chogenicity. The primary squamous cell carcinoma par-ticularly showed as a cavitary mass due to extensive cys-tic or necrotic change (Fig. 2). Posterior enhancementwas present for seven cases and this was absent forthree cases. Calcifications within the masses were seenin two cases, and these findings corresponded to mam-mographic calcifications. In one case, the US appear-ance of enlarged axillary lymph nodes showed as un-even cortical thickenings and the compression of thenodal hilums, which was considered as metastasis.

Histologic Correlation

The US-pathologic correlation is also included in Table1. On pathologic examination, the proportion of themetaplastic squamous components of breast carcino-


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A B

Fig. 1. Patient 5. A 62-year-old woman with metaplastic squa-mous breast carcinoma. A. Craniocaudal mammograms show a partially circumscribedoval mass in the outer portion of the right breast (arrows).B. Sonogram shows a complex echoic mass with posterior en-hancement. Note the presence of small intratumoral cystic areas(arrows).C. Photomicrograph shows the tumor consisted of cystic areas(arrow), necrosis, and hemorrhage (arrowheads) (Hematoxylin-eosin stain; original magnification ×40).

C

mas, including primary squamous cell carcinoma, wasmore than 70% in six cases, and this proportion was be-tween 30% and 60% in the four other cases. One casewith a circumscribed margin on US revealed a micro-scopically pushing margin. Of the three cases with par-tially circumscribed margins on US, one case showed amicroscopically pushing margin and two showed push-ing margins with an infiltrative portion. Among the sixcases with non-circumscribed margins on US, five caseswith the indistinct types showed infiltrative marginsand one case with the microlobulated type showedpushing margins on microscopic examination. All sixcases having complex echogenicity with solid and cysticcomponents on US contained macroscopic cystic ornecrotic portions on the pathologic specimens (Figs. 1and 2), and three of these six cases were combined withhemorrhage (Fig. 1). Among the remaining four cases,three showed macro or micro necrosis, and one showedmicrocystic necrosis with hemorrhage on the pathologicspecimens. In only one case, the positive axillary nodes

seen on US were pathologically proven to be metastasis.

Discussion

Metaplastic breast carcinomas have many differenthistologic entities, and these include spindle cell carci-noma, carcinoma with osseous metaplasia, carcinomawith pseudosarcomatous metaplasia, squamous cell car-cinoma with pseudosarcomatous stroma, fibrosarcoma-like squamous cell carcinoma and carcinosarcoma (4).Metaplastic carcinomas can generally be regarded asductal carcinomas that have undergone metaplasia intoa nonglandular growth pattern. The extent of metaplasiacan vary from a few microscopic foci to the complete re-placement of glandular growth (1). Squamous metapla-sia can arise in various benign and malignant condi-tions, and most commonly it arises from ductal carcino-ma (6). In most metaplastic carcinomas, the foci of tran-sition between invasive ductal carcinoma and the meta-plastic element were sometimes detected only after ex-


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A

BFig. 2. Patient 1. A 51-year-old woman with primary squamouscell carcinoma.A. Craniocaudal mammograms show an oval mass having a par-tially circumscribed margin in outer portion of left breast.B. Sonogram shows a complex echogenic mass having an indis-tinct margin with posterior enhancement. C. Photomicrograph shows large areas of intratumoral cystlined with squamous cell carcinoma that contains necrotic de-bris (arrow) (Hematoxylin-eosin stain; original magnification ×40).

C

tensive sampling. The mean age of our patients was 47 years, and this

was similar to the mean age of the patients in Park’s re-port (9), but this is more than 10 years younger than themean age in other previous reports (4, 9). This was simi-lar to the peak age of breast carcinoma in Korea, whichhas been noted to occur most frequently in the fifth andsixth decades of life, and this was about 10 yearsyounger than in the western countries (10).

Clinically, the first symptom of metaplastic squamousbreast carcinoma is a rapidly growing, palpable tumor;the mean and median sizes (3-4 cm) tend to be greaterthan those of ordinary breast carcinomas. In our study,all ten patients presented with a palpable breast massand the range of the longest diameter of the masses wasfrom 1.7 cm to 6.8 cm (the mean diameter was 3.7 cm).There was no predilection found for the left or rightbreast in the previous reports (9-12), and our findingswere consistent with these generalizations.

Cystic areas may occur in metaplastic breast carcino-ma as a result of necrosis and hemorrhage, and thesecystic areas are commonly associated with squamouscomponents (1, 13, 14). According to Park et al., 6 meta-plastic carcinomas (55%) showed complex echogenicitywith solid and cystic components on US, and 4 of these6 lesions also had hemorrhagic or cystic necrosis on thepathologic examination (9). Three cases of the fourmetaplastic carcinomas in Park’s report were squamoustypes. Samuels et al. have reported that the predomi-nantly squamous cell carcinomas and pure squamouscell carcinomas appeared as cystic masses on US, andcystic and necrotic areas that were evident on the grossand histologic examination were characteristic of squa-mous cell carcinoma (11). Dash et al. have reported thaton magnetic resonance imaging, primary squamous cellcarcinoma was of low intensity on T1WI and of high in-tensity on T2WI; the latter, however, was not sufficient-ly intense to represent a simple cyst, and this led to a di-agnosis of necrotic tumor (7). In our study, six of ten cas-es (60%) showed masses containing both anechoic andechogenic components on US, and in particular, the pri-mary squamous cell carcinoma appeared as a cavitarymass due to the extensive cystic or necrotic changes. Allof these six cases showed macroscopic cystic or necroticportions on the pathologic specimens, and three of thesesix cases were combined with hemorrhage. Althoughthe pathologic descriptions of the remaining four casesdid mention areas of cystic or necrotic change, these fea-tures could not be found on the US finding. This dis-

crepancy of the US and pathologic findings may havebeen due to the masses containing very small sized cystsor impacted necrotic debris. In addition, hemorrhagewithin the lumen may have simulated a solid mass onUS. The intratumoral cystic or necrotic portions causedthe posterior enhancement behind the mass that wasnoted on US.

Metaplastic carcinoma and primary squamous cellcarcinoma have been related with a low rate of axillarynodal metastasis in relation to the tumor size (11). Onlyone patient in this study had positive nodes; this patienthad a 3.7 cm palpable primary tumor with 70% squa-mous metaplastic components.

In the previous reports, malignant microcalcificationswere not a typical feature of metaplastic carcinoma andprimary squamous cell carcinoma (2, 6, 11). In ourstudy, 20% of the patients showed calcifications withintheir masses on US.

Some reports have revealed that the prognosis ofmetaplastic carcinoma and primary squamous cell carci-noma was worse than that of adenocarcinoma (3, 15).However, most authors believe that the prognosis wasessentially the same as that of ductal carcinoma (16, 17).Several prognostic factors associated with a poorer out-come for metaplastic carcinoma and primary squamouscell carcinoma include a large tumor size, the presenceof infiltrating margins, and the predominance of sarco-matous over the epithelial elements (3, 6, 12). The over-all 5-year survival rate for metaplastic carcinoma andprimary squamous cell carcinoma is approximately 40%and 64%, respectively (4, 6).

In conclusion, the metaplastic squamous breast carci-noma manifested at the time of presentation as a rapidlygrowing, relatively large mass. On US, there was com-plex echogenicity with solid and cystic components, in-distinct margins and posterior enhancement, and thiswas pathologically related to the presence of cysticnecrosis or hemorrhage. Malignant calcifications did notseem to be a usual finding. The axillary lymph nodeswere not frequently involved. Although these findingsare frequently seen for the other breast malignancies,metaplastic squamous breast carcinoma should be in-cluded in the differential diagnosis for breast masseswith a cystic component that is observed on US.

References

1. Rosen PP, Oberman HA. Invasive carcinoma. In: Atlas of tumorpathology: tumors of the mammary gland, 3rd series, fasc. 7.Washington, DC: Armed Forces Institute of Pathology, 1993;194-203


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2. Patterson SK, Tworek JA, Roubidoux MA, Helvie MA, ObermanHA. Metaplastic carcinoma of the breast: mammographic appear-ance with pathologic correlation. AJR Am J Roentgenol 1997;169:709-712

3. Oberman HA. Metaplastic carcinoma of the breast. A clinico-pathologic study of 29 patients. Am J Surg Pathol 1987;11:918-929

4. Wargotz ES, Norris HJ. Metaplastic carcinomas of the breast. IV.Squamous cell carcinoma of ductal origin. Cancer 1990;65:272-276

5. Fisher ER, Palekar AS, Gregorio RM, Paulson JD. Mucoepidermoidand squamous cell carcinomas of breast with reference to squa-mous metaplasia and giant cell tumors. Am J Surg Pathol 1983;7:15-27

6. Tashjian J, Kuni CC, Bohn LE. Primary squamous cell carcinomaof the breast : mammographic findings. Can Assoc Radiol J 1989;40:228-229

7. Dash N, Sharma P, Lupetin AR, Schapiro RL, Contractor FM.Magnetic resonance imaging appearance of primary squamous cellcarcinoma of the breast. J Comput Assist Tomogr 1987;11:359-363.

8. American College of Radiology. Breast imaging reporting and datasystem. 4th ed. Reston, Va: American College of Radiology, 2003

9. Park JM, Han BK, Moon WK, Choe YH, Ahn SH, Gong G.

Metaplastic carcinoma of the breast: mammographic and sono-graphic findings. J Clin Ultrasound 2000;28:179-186

10. Ministry of Health and Welfare in Korea. National cancer registryreport (1993.1.1-1993.12.31).1995.3

11. Samuels TH, Miller NA, Manchul LA, DeFreitas G, Panzarella T.Squamous cell carcinoma of the breast. Can Assoc Radiol J 1996;47:177-182

12. Brenner RJ, Turner RR, Schiller V, Arndt RD, Giuliano A.Metaplastic carcinoma of the breast: report of three cases. Cancer1998;82:1082-1087

13. Leiman G. Squamous carcinoma of the breast: diagnosis by aspira-tion cytology. Acta Cytol 1982;26:201-209

14. Tavassoli FA. Classification of metaplastic carcinomas of thebreast. Pathol Annu 1992;27:89-119

15. Toikkanen S. Primary squamous cell carcinoma of the breast.Cancer 1981;48:1629-1631

16. Eggers JW, Chesney TM. Sqamous cell carcinoma of the breast: aclinicopathologic analysis of eight cases and review of the litera-ture. Hum Pathol 1984;15:526-531

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대한영상의학회지 2004;51:669-674

상피 화생성 유방암의 초음파 소견 : 병리 소견과의 비교

1이화여자대학교 의과대학 이대목동병원 방사선과2이화여자대학교 의과대학 이대목동병원 병리과

신정희·황아실이·최혜영·성순희2·김유경·이선화

목적: 상피 화생성 유방암의 초음파 소견을 알아 보고 병리적 소견과 비교하고자 하였다.

대상과 방법: 8년간 10명의 상피 화생성 유방암을 가진 환자의 초음파 소견을 Breast Imaging and Reporting Data

System (BI-RADS) - US lexicon 에 근거하여 후향적으로 분석하였다. 이들 10명의 환자들은9명의 30% 이상

의 상피 화생을 가진 화생성 유방암과 1명의 원발성 상피세포암으로 구성되었다. 초음파 소견과 병리적 소견을 비

교하였다.

결과: 초음파상에서 종괴의 대부분은 타원형(70%), 불분명한 경계(50%). 평행한 방향(80%), 에코성의 달무리

(60%), 고형과 낭성 성분을 가진 복합성 에코(60%), 그리고 후방 증가 음영(70%)을 보였다. 석회화(20%)와 전

이성 액와 림프절(10%)의 소견은 드물었다. 병리적 소견에서 종괴의 반은 침윤성의 미세현미경적 경계를 보였다.

초음파상에서 복합성 에코를 보인 6예는 병리적으로 낭성과 괴사 부분과 연관되어 있었고 그 중 3예는 출혈을 포

함했다.

결론: 초음파상 상피 화생성 유방암은 병리적으로 고형과 낭성 부분과 연관된 복합성 에코, 불분명한 경계, 후방 음

영증가를 주로 나타냈다.

ultrasonographic findings of metaplastic squamous breast

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