Squamous carcinoma of the breast

Breast Implants and the Risk of Squamous Cell Carcinoma of the Breast: A Systematic Literature Review and Epidemiologic Study

Squamous cell carcinoma may arise primarily from the breast parenchyma (PSCCB) or from the periprosthetic capsule in patients with breast implants (breast implant-associated squamous cell carcinoma [BIA-SCC]). A systematic literature review was performed to identify all PSCCB and BIA-SCC cases, and to estimate prevalence, incidence rate (IR), and risk. Studies up to November 2023 were searched on PubMed, Web of Science, Google Scholar, and Cochrane Library for predefined keywords. The numerator for PSCCB and BIA-SCC was the number of cases obtained from the literature; the denominator for PSCCB was the female population aged from 18 to 99, and the denominator for BIA-SCC was the population with breast implants. Overall, 219 papers were included, featuring 2250 PSCCB and 30 BIA-SCC cases. PSCCB prevalence was 2.0 per 100,000 (95% CI, 0.2:100,000 to 7.2:100,000) individuals, with a lifetime risk of 1:49,509 (95% CI, 0.2:10,000 to 5.6:10,000); and BIA-SCC prevalence was 0.61 per 100,000 (95% CI, 0.2:100,000 to 1.3:100,000), with a lifetime risk of 1:164,884 (95% CI, 0.2:100,000 to 5.6:100,000). The prevalence of BIA-SCC is 3.33 times lower than that of PSCCB, while the prevalence of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is 3.84 times higher than that of primary breast ALCL. When comparing the BIA-SCC prevalence of 1:164,910 individuals with breast implants regardless of texture to the BIA-ALCL prevalence of 1:914 patients with textured implants, the BIA-SCC risk is 180 times lower than the BIA-ALCL risk. BIA-SCC occurs less frequently than PSCCB and considerably less than BIA-ALCL. The association between textured implants and BIA-SCC cases is relevant for patient education regarding uncommon and rare risks associated with breast implants, and ongoing vigilance, research, and strengthened reporting systems remain imperative.

Primary squamous cell carcinoma of the breast: report of two cases with HER2 overexpression

OBJECTIVE

To investigate the clinicopathologic features and immunophenotype of primary squamous cell carcinoma of the breast (PSCCB) with HER2 overexpression. Methods Two cases of PSCCB with HER2 overexpression were retrospectively reviewed, and the pathological features, immunophenotype and prognosis were discussed. Results The tumor showed malignant squamous cells arranged in sheets, groups and nests, forming keratin-pearl and intercellular bridges. Immunohistochemical (IHC) analysis showed that the tumor cells were positive for 34βE12, p63, CK5/6, E-cadherin and P120, while negative for ER and PR. Furthermore, HER2 overexpression showed strong continuous expression in cell membrane with a score of 3+ by IHC, or amplification by FISH. Conclusions PSCCB is a rare tumor in breast cancer and HER2 overexpression is rather unusual in PSCCB. The diagnosis mainly depends on the clinicopathologic features together with the immunophenotype. HER2 positive indicates poor prognosis. However, targeted therapy for HER2 may be a new hope for patients.

Breast Metaplastic Squamous Cell Carcinoma Diagnosed with Fine Needle and Core Biopsy: A Case Study

BACKGROUND Breast metaplastic squamous cell carcinoma (SCC) is a rare primary breast carcinoma, and overexpression of HER2 in this carcinoma is extremely uncommon. CASE REPORT We presented a case of a 48-year-old Asian female with breast metaplastic SCC. Fine needle aspiration biopsy (FNAB) and core needle biopsy (CNB) of the lesion were taken prior to surgical resection. FNAB smears demonstrated highly atypical squamous cells and a diagnosis positive for malignancy was rendered. CNB and a surgical resection specimen revealed invasive squamous carcinoma with keratin pearl formation and intercellular bridges. Further study demonstrated this was an unusual metaplastic SCC case with basal-HER2 (+) phenotype. HER2 has been linked to poor prognosis and response to therapy. CONCLUSIONS The pathological diagnosis of the breast metaplastic SCC was made initially by FNAB and CNB. Identification of basal-HER2 (+) phenotype was critical for selection of hormonal therapies and chemotherapy.

Roles of BCCIP deficiency in mammary tumorigenesis

Background

Dysregulated DNA repair and cell proliferation controls are essential driving forces in mammary tumorigenesis. BCCIP was originally identified as a BRCA2 and CDKN1A interacting protein that has been implicated in maintenance of genomic stability, cell cycle regulation, and microtubule dynamics. The aims of this study were to determine whether BCCIP deficiency contributes to mammary tumorigenesis, especially for a subset of breast cancers with 53BP1 abnormality, and to reveal the mechanistic implications of BCCIP in breast cancer interventions.

Methods

We analyzed the BCCIP protein level in 470 cases of human breast cancer to determine the associations between BCCIP and 53BP1, p53, and subtypes of breast cancer. We further constructed a unique BCCIP knockdown mouse model to determine whether a partial BCCIP deficiency leads to spontaneous breast cancer formation.

Results

We found that the BCCIP protein level is downregulated in 49% of triple-negative breast cancer and 25% of nontriple-negative breast cancer. The downregulation of BCCIP is mutually exclusive with p53 mutations but concurrent with 53BP1 loss in triple-negative breast cancer. In a K14-Cre-mediated conditional BCCIP knockdown mouse model, we found that BCCIP downregulation causes a formation of benign modules in the mammary glands, resembling the epidermal inclusion cyst of the breast. However, the majority of these benign lesions remain indolent, and only ~ 10% of them evolve into malignant tumors after a long latency. This tumor progression is associated with a loss of 53BP1 and p16 expression. BCCIP knockdown did not alter the latency of mammary tumor formation induced by conditional Trp53 deletion.

Conclusions

Our data suggest a confounding role of BCCIP deficiency in modulating breast cancer development by enhancing tumor initiation but hindering progression. Furthermore, secondary genetic alternations may overcome the progression suppression imposed by BCCIP deficiency through a synthetic viability mechanism.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-017-0907-5) contains supplementary material, which is available to authorized users.

Epidermal inclusion cyst in breast: Is it so rare?

Background:

Epidermal inclusion cyst in the breast (EICB) is very rare. It presents as breast lump mainly in peri-areolar region and needs to be differentiated from other breast lesions with predominance of squamous cells.

Aim:

To analyze the role of fine needle aspiration cytology (FNAC) in patients presenting with breast lump.

Materials and Methods:

The present study is a retrospective study over the period of past 2 years, where the patients presented with firm breast lumps. Six of these cases were diagnosed as EICB on FNAC. Smears from these cases were reviewed for cytomorphological findings and correlated with clinico-radiological details.

Results:

Patients ranged in age from 25 to 60 years, and female to male sex ratio was 2:1 (female 4, male 2). Mammography was done in women (4), which showed solid, well-defined mass lesions in peri-areolar region and were suggestive of benign breast lesions (3) and infective lesion (1). FNA was performed; Giemsa-stained smears showed predominantly mature benign squamous cell and anucleated squames in all cases, thus one of the cytological diagnoses was EICB. Five of these cases had histological confirmation.

Conclusion:

EIC of breast is not that rare lesion as considered. The patients may not seek medical attention because of small painless swelling; unless the lump increases in size or becomes painful. FNAC is confirmatory in the presence of a typical pultaceous aspirate and cytomorphological features of EIC. Thus, FNAC plays a crucial role in its diagnosis and management. Symptomatic cases should be readily excised and need histological correlation to rule out any potential complications that can arise in these cysts.

[Primary squamous cell carcinoma of the breast: clinical study and review of the literature]

From the analysis of our series and a review of the literature, we have done a summary of the clinicopathologic patterns and treatment of squamous cell carcinoma of the breast. It usually presents as a large palpable mass in a woman over 50 years old. There are no specific iconographic features, but a relative frequency of presentation as abscess or cyst. The overall and disease-free survivals are worse than other histological types of breast cancer. These neoplasms have a basal-like and triple negative profile and they respond poorly to standard treatment of breast carcinomas. They are usually treated by radical surgery. Optimal chemotherapy regimens is not yet determined and platin based chemotherapy could offer an effective alternative as the developpement of specific targeted therapies (anti Her1) could do.

Primary intracystic squamous cell carcinoma of the breast: A case report and review of the literature

Primary intracystic squamous cell carcinoma (SCC) of the breast is an extremely rare entity and has a low incidence in comparison with other breast cancers. We report a rare case of primary intracystic SCC in a 45-year-old woman who presented with a cystic lump in the right breast. Cytological smears of the fluid aspirated from the breast tumor revealed malignant squamous cells dispersed in single and occasional groups along with numerous cyst macrophages, suggesting cystic SCC. Histological study of the mastectomy specimen confirmed the diagnosis of primary intracystic SCC. Although the presence of abundant foamy macrophages in the background of fine needle aspiration cytology smears of the breast suggest benign breast lesion, when associated with malignant squamous cells, these suggest cystic primary SCC or metastatic SCC. The primary SCC should not be confused with metaplastic change in other breast carcinomas.

Ruptured epidermal inclusion cysts in the subareolar area: sonographic findings in two cases

Epidermal inclusion cyst of the breast is an uncommon benign lesion and it is usually located in the skin layer. We report here on two cases of ruptured epidermal inclusion cysts in the subareolar area, which is a very unusual location for these cysts and these lesions can be mistaken for breast malignancies.

Squamous cell carcinoma of the breast in the form of an intracystic tumor

Squamous cell carcinoma of the breast is thought to arise through metaplasia of ductal carcinoma cells. We report a case of pure squamous cell carcinoma of the breast with features of intracystic tumor, which was considered to have arisen from metaplastic squamous epithelial cells lining the cyst wall. A 71-year-old woman presented at our hospital with a 40 x 30-mm mass in the lower outer quadrant of the right breast. Mammography revealed a round, high-density mass, which had a mostly regular but partially irregular margin. Ultrasonography demonstrated a solid tumor with an irregular shape protruding into a cystic space, suspicious of intracystic carcinoma. Aspiration cytology confirmed squamous cell carcinoma. A modified radical mastectomy was performed. Histopathologically, the intracystic tumor was a pure squamous cell carcinoma. The epithelial cells lining the inner cyst wall showed mostly squamous metaplasia, and there was continuity between these cells and the squamous cell carcinoma. 13 months later, the patient is free of disease with no adjuvant therapy.

Pure primary squamous cell carcinoma of the breast: A rare presentation and clinicopathologic comparison with usual ductal carcinoma of the breast

Pure and primary squamous cell carcinomas of the breast are exceedingly uncommon lesions. To the best of our knowledge, based up on review of the literature, only four studies of patients with these tumors, which presented clinically as breast abscess, have been reported previously. We present a woman who sought medical attention for breast pain and was initially diagnosed with a breast abscess. When she did not respond to antibiotic therapy, an incision as well as drainage was performed. Histologic examination of the material revealed a pure squamous cell carcinoma. An extensive work up ruled out other primary sites. She was treated with mastectomy and radiation therapy and has seen disease-free 3 years postdiagnosis. We also review the literature for presenting features, value of imaging studies, role of cytology in diagnosis, and therapy of such tumors in comparison to the usual ductal carcinomas of the breast.

Epidermal cyst of the breast mimicking malignancy: clinical, radiological, and histological correlation

BACKGROUND

Epidermal cyst of the breast is a rare benign intramammary lesion; however, a common finding in other parts of the body and most often located in the scalp, back, and neck. Only a few cases of epidermal cysts of the breast have been reported in literature.

CASE REPORT

The patient presented with a small movable left breast lump. Mammography and ultrasonography did not show features of a benign lesion. Ultrasound-guided core biopsy was undertaken. Histology showed an epidermal cyst. The patient returned with an inflammation at the puncture site and a small abscess seen on ultrasound. The abscess was removed surgically.

CONCLUSION

Mammographic and sonographic features of an epidermal cyst may mimick a malignant lesion. Biopsy can result in complications, such as inflammation. In addition, an association between epidermal cyst and squamous carcinoma has been reported. Therefore, it is recommended that these lesions are resected.

Primary Pure Squamous Cell Carcinoma of the Breast

Primary squamous cell carcinoma (SCC) of the breast is an extremely rare tumor. It is diagnosed when the malignant cells are entirely of squamous type, the tumor is independent from overlying skin, and other primary SCC sites are excluded. This report presents clinical, radiologic, and histologic correlative findings of a patient diagnosed with pure SCC of the breast. Literature review suggests that primary SCC tumors of the breast are large, often cystic lesions, with a low rate of nodal involvement, no expression of estrogen and progesterone receptors, and resistance to the chemotherapy regimens commonly used in breast cancer.

Primary squamous cell carcinoma (SqCC) of the breast

Primary squamous cell carcinoma (SqCC) of the breast is a rare tumor that presents a unique biologic behavior. Thus, it challenges the justification for routine axillary dissection and adjuvant therapy. A MEDLINE search of all reported cases of primary SqCC of the breast was performed. Data on lymph node status, estrogen receptor (ER) and progesterone receptor (PR) status, and surgical and adjuvant treatment modalities were collected. We add three cases from our own experience. SqCC has several unique biologic characteristics; it is associated with a lower rate of lymph node metastasis at presentation (22% vs. 40-60% for infiltrating ductal carcinoma [IDC]) and a significant rate of distant metastasis without lymph node involvement. ER and PR receptor levels are usually very low. Because lymph node involvement plays a lesser prognostic and therapeutic role in this disease, we propose a more selective approach (i.e., sentinel node biopsy). The issue of adjuvant treatment remains unresolved, owing to lack of data. Surgical and medical treatment of SqCC of the breast should be tailored to fit its distinct biologic characteristics. The 5-fluorouracil-doxorubicin-cisplatin combination may be warranted in lieu of the combinations used for IDC.

Squamous cell carcinoma of the breast: clinico-pathologic implications and outcome

AIMS

Pure squamous cell carcinoma (SCC) of the breast is a rare tumour and little is known about long-term outcome. We report our experience of a consecutive series of patients.

METHODS

All patients with SCC treated at our institution between 1970 and 2001 were included. The pathological features, outcome and prognosis were studied.

RESULTS

Eleven patients were identified. The median age was 55 (38-90) years and median follow-up was 62 (3-332) months. Four tumours were T1, three were T2 and three were T3 (one tumour size was unknown). There were seven poorly differentiated and three moderately differentiated SCC. Tumour grade could not be assessed in one patient. Primary treatment was mastectomy in six patients, wide local excision in four patients and radiotherapy in one patient. There was lymph node (LN) involvement in two patients. Oestrogen receptor status was assessed in seven patients and only one tumour was positive. Adjuvant chemotherapy was given to three patients and five patients received adjuvant radiotherapy. Two patients developed local recurrence at 5 and 12 months and three patients developed distant metastasis at 2, 36 and 306 months. Three patients were treated with chemotherapy at recurrence. Three patients have died of the disease, two are alive with disease and six remain well. The 2- and 5-year overall survival was 80% (SE=13%) and 67% (SE=16%) respectively. Large tumour size and positive LN status were prognostic indicators of poor outcome.

CONCLUSION

SCC of the breast adopts an aggressive course with outcome comparable to poorly differentiated breast adenocarcinoma.

A case of primary squamous cell carcinoma of the breast with rapid progression

Primary squamous cell carcinoma of the breast is a rare disease for which no definite treatment or prognosis has been established. This report describes our experience with one case of primary squamous cell carcinoma of the breast that ended in death after rapid progression. The patient was a 58 year old woman who visited our hospital complaining of a growing tumor and pain in the right breast. Ultrasonographically the tumor consisted of solid tumor and a large cyst. Squamous cell carcinoma was diagnosed by fine-needle aspiration cytology. Neoadjuvant CEF was given, but the tumor continued to grow, so CEF was discontinued after one course and modified radical mastectomy was performed subsequently. There was no evidence of metastasis to lymph nodes. About 5 months post operatively CT of the head and chest X-ray demonstrated metastatic lesions in the brain and lungs. Resection of the cerebral tumor was performed. About 1 month after the operation, however, a new metastatic brain tumor was found and the patient later died.

Acantholytic Variant of Squamous Cell Carcinoma of the Breast: A Case Report

Primary squamous cell carcinoma of the breast is a rare clinical entity. Two large review series found only five cases out of a total of 8351 breast malignancies. This case report presents a patient with metaplastic, pseudoangiosarcomatous carcinoma or acantholytic variant of a squamous cell carcinoma of the breast. This diagnosis was based on the histological finding of highly atypical, acantholytic squamous cells. Because the tumor stained positive for keratin and negative for factor VIII, the diagnosis of angiosarcoma was ruled out. Although only scattered case reports have been published on this histological variant, these tumors tend to follow an aggressive course.

Gestational squamous cell carcinoma of the breast: an unusual mammary tumor associated with aggressive clinical course

We report two cases of squamous carcinoma of the breast detected during the gestational period. One woman was post-partum and lactating; one was in the first trimester of pregnancy. The lesions were clinically palpable, multifocal, and measured more than 5 cm in their largest dimension; both had a cystic appearance. They were treated with radical mastectomy. One patient received pre-operatory chemotherapy. Histologically, the tumors were poorly differentiated squamous cell carcinomas. No areas of ordinary duct differentiation were seen. Lymph nodes contained metastatic squamous carcinoma in both cases. Tumor cells were negative for estrogen and progesterone receptors. Also, they expressed a high proliferative index and several markers of tumor progression, including cErb-B2, p53 protein, bcl-2, and epidermal growth factor receptor. One patient died of tumor 5 months following breast surgery and had extensive metastases proven at autopsy. The other patient had evidence of pulmonary metastases: following cisplatin therapy, she underwent clinical remission. This study shows that squamous carcinoma of the breast may occur in pregnant or lactating women: it appears clinically distinguishable from the non-gestational type that is usually associated with a better prognosis and occurs in peri- or postmenopausal women.

Squamous cell carcinoma of the breast: a clinical approach

BACKGROUND

Squamous cell carcinoma (SCC) of the breast is rare. It remains unclear whether a "pure" form of SCC exists or if all known cases actually represent an extreme form of squamous metaplasia within adenocarcinoma. Due to its rarity and controversy over its definition, there are no good data on appropriate management and prognosis.

METHODS

All cases of breast carcinoma indexed at our institution were reviewed to identify seven cases where squamous metaplasia was a significant component of the pathologic diagnosis. Slides and electron micrographs were reviewed by a single pathologist. Clinical information was obtained from medical records.

RESULTS

These cases support the concept of a disease continuum with varying degrees of squamous metaplasia. When tumors identified as "pure" SCC on light microscopy are subjected to ultrastructural analysis, either separate squamous and glandular cells are present or both histologic features are noted to coexist in the same cell.

CONCLUSIONS

Identification of "pure" cases of SCC appears clinically unimportant. All patients presented with advanced disease, thus necessitating aggressive management regardless of histology. Mastectomy was performed due to large tumor size and adjuvant chemotherapy given rather than hormones because of receptor negativity. The mixed histology should direct future drug choice. The role of radiation remains unclear.

Primary squamous cell carcinoma of the breast: sensitivity to cisplatinum-based chemotherapy

Primary squamous cell carcinoma (SCC) of the breast is a rare malignancy whose optimal treatment and prognosis are unknown. A patient with SCC whose tumor responded dramatically to chemotherapy as part of multimodal treatment is presented. A 61-year-old woman had a palpable 5.5-cm tender left breast mass with overlying skin edema and erythema and irregular margins by mammography. Fine needle aspiration revealed malignant squamous cells with keratinization; incisional biopsy confirmed SCC. Extensive evaluation for an extramammary primary site of disease was negative. Neoadjuvant cisplatinum and 5-fluorouracil (5-FU) led to tumor shrinkage and complete resolution of pain and erythema. Modified radical mastectomy with post-operative chest wall radiation were performed. Neither residual invasive carcinoma nor metastatic nodal disease was found, though intraductal carcinoma with marked squamous features was identified. The patient remains disease-free 2.5 years after diagnosis. Cisplatinum-based chemotherapy should be considered in the treatment regimen of this disease.

Primary squamous cell carcinoma of the breast

A patient with pure primary squamous cell carcinoma (SCC) of the breast is reported. The patient was a 72 year old female who presented with a 4 month history of an enlarging left breast mass. Surgery involved a radical mastectomy and this was followed by post-operative radiotherapy and chemotherapy. The patient died of extensive metastatic disease some four months after surgery. The various characteristics of SCC of the breast are briefly discussed. A sub-group of SCC of the breast is identified among reported cases in which the clinical course is characterised by a very rapid growth, extremely aggressive behaviour and early metastasis.

Metaplastic carcinomas of the breast. IV. Squamous cell carcinoma of ductal origin

The clinical and pathologic features of 22 examples of pure ductal squamous cell carcinoma (SqCC) of the breast are reported. All patients were women with a mean age of 53 years. Only two of the 19 women with axillary dissection had metastases, but one woman had a positive supraclavicular lymph node in the presence of negative axillary nodes. All metastases were squamous carcinoma. All patients were eligible for a minimum of 5 years' follow-up; the cumulative 5-year disease-specific survival rate was 63%. Eight women developed metastases and one also developed local recurrence, all within 2 years, and all eight died from tumor within 4 years of initial therapy (mean, 2 years). Prophylactic postoperative radiation therapy and radiation for lymph node metastases at initial surgery did not prolong survival as four of the five recipients died from tumor. Although there were no statistically significant gross or histologic differences between recurrent and nonrecurrent neoplasms, larger neoplasms tended to metastasize. Immunohistochemical study for S-100 protein identified an immunoreactive cell component in five of seven neoplasms tested. This and light microscopic findings suggest myoepithelial proliferation, differentiation, or origin.

Spindle cell carcinoma of the breast: case report and review

Spindle cell carcinoma is a distinct, but unusual, variant of squamous cell carcinoma. It is seen most frequently in the upper aerodigestive tract and esophagus. The natural history seems to be similar to that of the more typical squamous cell carcinoma. A case of spindle cell carcinoma arising from the ductal epithelium of the breast is reported. The light and electron microscopic histology is described. A review of the literature suggests that this rare neoplasm should be managed in a fashion similar to that for more common types of epithelial breast duct malignancies.

Pure squamous cell carcinoma of the breast

Pathological curiosities have always fascinated the surgical community, and management of breast cancer by the physician has, at times, revealed such rarities. A recent case of squamous cell carcinoma in a clear fluid breast cyst has prompted a review of our experience with this rare pathology, and allowed us to make the following statements: We propose that squamous cell carcinoma of the breast arises from ductal metaplasia. When the T.N.M. system is applied to the squamous cell lesion, the apparent poor prognosis that it is believed to carry may not be so apparent. If no other primaries are identified after extensive metastatic work-up, surgical therapy consisting of total mastectomy with complete axillary dissection, is very effective in local control of tumor progress. Nodal status will indicate the need for additional modalities of therapy.

Epidermal cyst of the breast

Two cases of epidermal cyst of the breast are presented. Mammography and ultrasonography merely confirmed that the masses were solid. As is usual with these extremely rare lesions, the initial diagnoses (fibroadenoma and carcinoma) were incorrect.

Infarction and squamous metaplasia of intraductal papilloma: a benign breast lesion that may simulate carcinoma

Infarction of intraductal papillomas is uncommon. Six lesions of this type was referred to the authors as diagnostic problems, and two additional cases were found in a review of in-patient material. The patients' median age was 62 years (range, 30 to 81 years), and in each case the mass had been asymptomatic. Although the architectural pattern of the papillomas remained intact, ischemic necrosis rendered histologic evaluation difficult. Squamous metaplastic epithelium was present in three cases. Distortion of residual viable ductal epithelium by fibrosis at the periphery of the papillomas closely simulated invasive carcinoma. The appearance of the lesion on low-power magnification, the absence of malignancy elsewhere in the sample, and the absence of cytologic features of malignancy are useful criteria for distinguishing this lesion from carcinoma. None of these lesions recurred in the six patients for whom follow-up information was available (follow-up period, one to 20 years).

Squamous cell carcinoma of the breast: a clinicopathologic analysis of eight cases and review of the literature

Malignant neoplasms of the female breast composed of squamous cells are rare and constitute a particularly poorly understood facet of breast disease. Two pure squamous cell carcinomas ( SCCs ) of the breast and six tumors that displayed various combinations of malignant squamous elements and ductal breast adenocarcinoma were identified. Electron microscopy confirmed the diagnosis of SCC in two cases by the demonstration of regularly spaced desmosomes, tonofilament bundles, and keratohyaline granules. A review of the literature indicated that breast cancers with components of SCC are histologically variable. Approximately 30 cases of pure SCC and 80 cases of mixed adenocarcinoma and SCC (adeno-SCC) have been reported. Some of these squamous epithelium-containing tumors have displayed areas of cyst formation, spindle cell metaplasia, and pseudosarcomatous desmoplastic response, or origins in preexisting breast lesions, such as cystosarcoma phyllodes or dermoid cysts. Although this variability indicates a heterogeneous group of neoplasms, the overall prognosis for carcinomas of the breast with malignant squamous elements appears to be quite similar to that for ordinary breast adenocarcinomas of similar size and stage.

Carcinoma of the breast with pseudosarcomatous metaplasia

Twenty-six cases of breast carcinoma demonstrating pseudosarcomatous metaplasia are described, and their clinical and pathologic aspects are correlated. The metaplastic elements include mature and immature bone, cartilage, myxoid stroma, loose fibromyxoid and dense spindle-cell stroma, and anaplastic stroma with giant cell features. Light and electron microscopic examination demonstrated an orderly sequence of transformation and dedifferentiation of epithelial cells to become undifferentiated mesenchymal cells. These tumors are more aggressive than purely epithelial carcinomas. The overall survival rate was 44%. Five-year survival figures for TNM Stages I, II, and III lesions were 56%, 26%, and 18%, respectively. The incidence of lymph node metastasis was 25% despite the large size of many of these tumors. Systemic metastases replicated the range of metaplastic elements seen in the primary site. Patients with tumors composed predominantly of pseudosarcomatous elements had worse prognoses than those with predominantly epithelial components (28% versus 62%, 5-year survival).

Spindle cell carcinoma of the breast: four cases and review of the literature

The clinical and morphologic features of four cases of spindle cell carcinoma of the breast are presented, and the comparable features of 35 previously reported cases are reviewed. All tumors contained histologically malignant squamous carcinoma that tended to blend with a spindle cell "pseudosarcomatous" stroma. Patients with this rare tumor tend to present at the same age as patients with other histologic types of breast carcinoma, but the spindle cell tumors are somewhat larger. Although the number of reported patients is too small to serve as a basis for firm conclusions, the prognosis appears similar to that for patients with conventional infiltrating duct carcinoma of the breast.

Primary squamous cell carcinoma of the breast

Upon reexamination of about 4000 breast cancer biopsies, three pure primary squamous cell carcinomas (SCC) were found. The light and electron microscopic findings of these three cases are described. The carcinomas seemed to originate from the glandular tissue of the breast and followed an extremely aggressive clinical course. SCC must be regarded as a separate entity distinct from adenocarcinoma of the breast with squamous cell metaplasia.

Spindle cell carcinoma of the breast. A clinocopathologic and ultrastructural study

The clinical and pathologic features in six cases of spindle cell carcinoma of the breast were reviewed. Histologically this tumor is characterized by sheets of spindle cells often containing squamous epithelial islands and numerous cystic spaces lined by epidermoid carcinoma or benign appearing squamous epithelium. Areas of transition from the squamous epithelium or epidermoid carcinoma to malignant spindle cells were seen in all cases. Features of squamous epithelial differentiation were found in the spindle areas of the one tumor examined by electron microscopy. The prognosis in this neoplasm is similar to that in the more common breast carcinomas. Spindle cell carcinoma therefore should be distinguished from fibrosarcoma, stromal sarcoma, and carcinosarcoma. Moreover, it should be separated from the broader category of "metaplastic carcinoma," since this term includes a heterogeneous group of tumors of uncertain histogenesis and prognosis.