Cancers metastatic to the breast

Case report: Metastatic ovarian mucinous carcinoma to the breast: diagnostic challenges and pitfalls

Metastases to the breast from extramammary sources are extremely rare, with the ovary, primarily high-grade serous carcinoma, being the most common origin. We report a case of breast metastases from advanced stage ovarian mucinous carcinoma in a 48-year-old female- a case hitherto unreported in the literature. The case is noteworthy for its atypical presentation marked by an areolar rash, clinically suggestive of Paget disease of the nipple. This unique clinical scenario, coupled with histopathological examination revealing in-situ-like carcinoma component, posed a diagnostic challenge in discerning the tumour origin. We emphasize the need for heightened awareness among pathologists to avoid misdiagnosing metastatic carcinomas as primary breast tumours, a potential pitfall with significant clinical implications.

Unusual Metastasis of Gastric Signet Ring Cell Carcinoma to the Breast: A Case Report of a Young Moroccan Patient

Although gastric cancer is known to be an aggressive tumor that can spread throughout the body, breast metastases are uncommon. This entity is rarely reported in the literature, with an estimated incidence of 0.5 to 1.3%. We report a case of a rare association between a gastric subtype of signet ring cell carcinoma and metastasis to the breast. This uncommon situation is only documented through case reports. Most breast metastases have been detected after diagnosis of primary gastric cancer, during the first year. Several risk factors have been suggested to explain the aggressive behavior of these tumors, which correlates with very poor prognosis and short survival. We report the case of a 22-year-old female patient presenting with widespread metastatic gastric signet ring cell carcinoma with an unusual secondary site in the breast. The diagnosis was confirmed by immunohistochemistry (IHC) and radiology, and the patient was treated with palliative chemotherapy in accordance with the decision of the multidisciplinary tumor board.

Breast mass - An uncommon clinical manifestation of ovarian carcinoma: A case report and brief literature review

Metastasis from non-mammary malignant neoplasms to the breast is rare and represents 0.2%-1.3% of all breast malignancies. Fine needle aspiration cytology (FNAC) is the first line of investigation for any breast lump and cyto-morphological appearance of primary breast malignancies is well documented. Occasionally metastasis to the breast may be the initial presentation and can masquerade clinically as primary breast malignancy. The present case describes the clinical and cytological challenges in an unusual case of ovarian carcinoma with initial presentation as breast mass, mimicking as inflammatory carcinoma. In cytology the breast lesion was initially misdiagnosed as primary breast carcinoma and subsequently diagnosed as metastatic ovarian carcinoma based on core needle biopsy findings, aberrant immuno-profile and clinical findings; thus making the complex case worthy of discussion.

Case Report of Renal Cell Carcinoma Metastasis to the Breast

Metastases from other primary malignancies to the breast are extremely rare, with an incidence of up to 2%. Renal cell carcinoma (RCC) is known to form micrometastases in unusual organs. This report describes a case of a RCC metastasis to the breast that was identified 20 years after nephrectomy. The patient, a 68-year-old female, presented after a new abnormality was found on a screening mammogram. The biopsy, which was reviewed by several pathologists, revealed a renal cell carcinoma metastasis. Imaging confirmed no other metastases, and she was treated with a partial mastectomy. This case highlights how RCC metastases can be found many years after a nephrectomy, and staining for RCC should be considered in patients with this history and a newly identified breast mass.

Metastatic non-Hematopoietic Neoplasms to the Breast: A Study of 238 Cases

AIMS

The aim of this study was to review the clinicopathologic characteristics of metastatic non-hematopoietic malignancies to the breast, in order to identify salient features for practicing pathologist that are useful in distinguishing metastatic lesions from primary breast neoplasms.

METHODS AND RESULTS

A total of 238 cases were identified during the period from January 2005 to January 2015. Clinicopathologic features of these cases were retrospectively reviewed. Primary tumors included melanoma (99, 42%), serous carcinoma (35, 15%), neuroendocrine neoplasm (32, 13%), sarcoma (23, 10%), and adenocarcinoma from various organs (47, 20%), among others. Most metastases were unilateral (223, 94%) and unifocal (206, 87%), and were detected radiographically (167, 70%). Concurrent ipsilateral axillary metastasis occurred in 33 (14%) patients. Among 238 cases, 41 had metastatic disease to the breast concurrently or preceding the primary cancer diagnosis. Notable, in 39 (16%) cases, breast metastasis was the first clinical presentation of disease, and 16 (41%) of these cases were initially misdiagnosed as breast primaries. In contrast, with known history of non-mammary primary tumors, only 4 of 197 (2%) cases were misdiagnosed (p<0.0001).

CONCLUSIONS

Metastatic tumors share many overlapping features with breast primary carcinomas. However, cases with a well-circumscribed tumor, lack of in situ component, ER/PR negativity, and unusual morphologic features should raise the consideration of metastatic disease. While clinical history is paramount for correct diagnosis, metastasis to the breast as the first clinical presentation is not uncommon.

Unusual presentation of a small cell lung cancer with bilateral breast metastases: Case report and a brief review of the literature

Small cell lung cancer (SCLC) is a smoker's disease and occurs almost exclusively in smokers. SCLC is a high-grade neuroendocrine tumor and commonly presents as a central tumor with bulky mediastinal adenopathy. It is notorious for causing widespread disease and paraneoplastic syndromes. The usual sites of metastasis include the liver, brain, bone, and adrenals. SCLC presenting with breast metastasis is unusual; however, there are reports of unilateral and bilateral breast metastases. SCLC with bilateral breast metastases is extremely rare, with only five previously reported cases available in the literature. We are taking this opportunity to report and add to the growing literature on the unusual presentation of a small cell lung cancer with bilateral breast metastases.

Osteosarcoma of the Right Lower Femur With Breast and Axillary Lymph Node Metastasis: A Rare Case Presentation

Osteosarcoma is the most common skeletal malignancy and commonly metastasis to lung and bone. Here we report a case of osteosarcoma of the right knee with metastasis to the lower and inner quadrant of the breast along with axillary, mediastinal, retroperitoneal and inguinal lymphadenopathy with lung and liver metastasis. The diagnosis of breast metastasis was confirmed by ultrasonography-guided biopsy and immunohistochemistry (IHC). So this report highlights the rarest metastasis to breast and axillary lymph node from an osteosarcoma of the right knee primary.

Ovarian Cancer With Breast Metastasis and Two Pathogenic Variants of BRCA1 Gene

Ovarian cancer is the second most common gynecologic cancer after uterine cancer in the United States. Ovarian cancer ranks sixth in cancer deaths among women, accounting for more deaths than other female reproductive system cancers. Breast metastasis in ovarian cancer is a rare presentation and predicts a poor prognosis and challenging management. Our case is a 42-year-old Chinese woman with high-grade serous ovarian carcinoma that presents with metastasis to the breast during the course of her illness. Genetic evaluation of the ovarian tumor showed two BRCA1 pathogenic variants. Germline pathogenic variant of c.2110_2111DelAA and a somatic variant of c.4071_4096+14del40. Our patient was offered different treatment regimens but showed progression of her disease. The low survival rate and high recurrence rate in ovarian cancer show that we still need to investigate our current approved treatments. Our report aims to shed light on the genetic evaluation of ovarian tumors and treatment options available in refractory cases of progressive ovarian cancer. Furthermore, we explain our investigational therapy regimen and the reasoning behind it.

Breast metastasis from medullary thyroid carcinoma: a report of a case

Background

Metastasis to the breast is rare. We herein report a patient with metastatic medullary thyroid carcinoma to the breast for whom measuring the calcitonin level was an important clue to the correct diagnosis.

Case presentation

A 54-year-old woman visited our hospital for the treatment of recurrent metastatic medullary thyroid carcinoma due to multiple endocrine neoplasia 2A and breast cancer. Positron emission tomography performed before the operation for metastatic medullary thyroid carcinoma recurrence in the neck showed the accumulation of ¹⁸F-fluorodeoxyglucose in the bilateral breast at sites other than the disease in the neck. Ultrasonography revealed multiple tumors in both breasts. A core needle biopsy of three breast tumors was performed. Microscopically, the tumor cells showed solid growth and did not show a tubular structure. She was diagnosed with triple-negative invasive ductal carcinoma. Post-operative positron emission tomography was performed as the serum calcitonin level increased after the operation. The accumulation of ¹⁸F-fluorodeoxyglucose in the bilateral breast tumors and lymph nodes in the neck was noted. The possibility of the breast tumors being metastasis of metastatic medullary thyroid carcinoma was considered. Needle aspiration was performed for three breast tumors. The calcitonin level of the washout fluid was measured and found to be ≥ 17,500 pg/mL. Immunohistochemistry showed that the tumor cells were calcitonin-positive and gross cystic disease fluid protein-15-negative. Vandetanib was started as recurrent metastatic medullary thyroid carcinoma with breast metastasis was finally diagnosed. The serum calcitonin level decreased after 1 month.

Conclusion

Although breast metastasis of medullary thyroid carcinoma is rare, a correct diagnosis is indispensable for appropriate treatment. When a breast tumor shows atypical morphological features for breast cancer according to the histopathology in a patient with a history of cancer, metastasis to the breast should be considered. Calcitonin measurement of the needle washout fluid was useful for confirming metastatic medullary thyroid carcinoma.

Micropapillary Bladder Cancer Metastatic to the Breast: A Case Report and Brief Literature Review

BACKGROUND

Bladder cancer (BC) usually metastasizes to the lymph nodes, bone, lung, liver and peritoneum, but rarely in the breast.

CASE REPORT

We present a case of a 66-year-old female diagnosed with a massive bladder tumor, who presented a right mammary nodule after neo-adjuvant chemotherapy. A biopsy of the nodule did not permit a definite diagnosis of metastatic spread, which was confirmed by excision of the nodule. In the literature, we found only 7 other similar cases of BC metastasis to the breast. Currently, a non-invasive method for differentiating a breast metastasis from primary cancer is lacking, although there are some clinical and radiological aspects that may help the diagnosis. Histological examination provides diagnostic certainty.

CONCLUSION

Breast metastases from BC are unusual and consequently difficult to identify without non-invasive tools. Clinical history and histological study play a pivotal role in determining the correct diagnosis.

PET/CT Variants and Pitfalls in Breast Cancers

There are a number of normal variants and pitfalls which are important to consider when evaluating F-18 Fluorodeoxyglucose (FDG) with Positron Emission Tomography (PET) in breast cancer patients. Although FDG-PET is not indicated for the initial diagnosis of breast cancer, focally increased glucose metabolism within breast tissue represents a high likelihood for a neoplastic process and requires further evaluation. Focally increased glucose metabolism is not unique to breast cancer. Other malignancies such as lymphoma, metastases from solid tumors as well as inflammatory changes also may demonstrate increased glucose metabolism either within the breast or at other sites throughout the body. Importantly, benign breast disease may also exhibit increased glucose metabolism, limiting the specificity of FDG-PET. Breast cancer has a wide range of metabolic activity attributed to tumor heterogeneity and breast cancer subtype. Intracellular signaling pathways regulating tumor glucose utilization contribute to these pitfalls of PET/CT in breast cancer. The evaluation of axillary lymph nodes by FDG-PET is less accurate than sentinel lymph node procedure, however is very accurate in identifying level II and III axillary lymph node metastases or retropectoral metastases. It is important to note that non-malignant inflammation in lymph nodes are often detected by modern PET/CT technology. Therefore, particular consideration should be given to recent vaccinations, particularly to COVID-19, which can commonly result in increased metabolic activity of axillary nodes. Whole body FDG-PET for staging of breast cancer requires specific attention to physiologic variants of FDG distribution and a careful comparison with co-registered anatomical imaging. The most important pitfalls are related to inflammatory changes including sarcoidosis, sarcoid like reactions, and other granulomatous diseases as well as secondary neoplastic processes.

Renal Cell Carcinoma Metastasis to the Breast: A Rare Presentation

Worldwide breast malignancy is the most common cancer in women; however, metastases to the breast from extramammary malignancies are very rare and only a few sporadic cases are reported in the international literature. In this article, the authors report a case of a 73-year-old woman, who underwent nephrectomy for clear cell renal cell carcinoma and 3 years later presented with a breast metastasis from renal cell carcinoma (clear cell type).

Metastasis to breast from ovarian cancer and primary ovarian cancer concurrently diagnosis

Metastasis to breast from ovarian cancer is very rare, and it is very difficult to distinguish the primary breast cancer from the secondary one. In our case, a 61-year-old woman presented to the hospital with complaints of lower abdominal pain and distention. Abdominal-pelvic computed tomography (CT) imaging revealed a solid ovarian cystic tumor with numerable ascites in the abdominal cavity and disseminated peritoneal carcinomatosis. To confirm the presence of metastasis in other organs, a preoperative imaging studies including chest CT was performed. Chest CT imaging revealed an enlargement of both the axillary lymph nodes (r/o metastatic lymphadenopathy) and breast imaging studies (breast sonography and mammography) revealed masses penetrated the pectoralis major muscle in the left breast and metastatic lymphadenopathy in Lt axilla. The core needle biopsy result of breast lesion showed unknown origin carcinoma with micropapillary features and no psammoma bodies. So, we could not distinguish primary breast cancer and breast metastasis from ovarian cancer because breast metastasis from ovary could be contained psammoma bodies, generally. Although the possibility of primary breast cancer could not be ruled out absolutely, the neoadjuvant chemotherapy included Paclitaxel and Carboplatin is known to be effective for both breast and ovarian cancer. So after neoadjuvant chemotherapy, mastectomy concurrently with ovarian cancer surgery was performed. The histopathologic features of the ovaries and breast were similar and psammoma bodies also could be observed, which were not detected in previous core needle biopsied specimen. And lymph nodes from the breast and the ovaries also showed consistent findings. Combined with histopathologic report and medical records, the final diagnosis confirmed as a metastasis of ovarian cancer to breast. After surgery, the patient has continued with metastatic ovarian cancer specific treatment. Breast metastatic tumors must be distinguished from primary breast tumors to avoid any unnecessary surgery. It might be difficult to diagnosis precisely by using only core needle biopsy because of inadequate specimen volume. Although surgical resection may be effective for both diagnosis and palliative treatment, further studies focused on less invasive biopsy are needed for exact histopathological diagnosis.

A case report of multiple bilateral breast metastases after colorectal cancer

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CRC metastasizes commonly to the regional lymph nodes, liver, lung, and rarely to breast.

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The radiologic investigations can play a role in the differentiation between the diagnosis of primary breast cancer and metastases.

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Immunohistochemically, the majority of breast adenocarcinomas are: negative for CDX2 and CK20 and positive for CK7, while colorectal adenocarcinomas are: positive for CDX2 and CK20, and negative for ER, PR, HER2, and CK7.

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The management plan of CRC metastases to the breast is complex and requires a multidisciplinary team.

Introduction and importance

Although primary breast cancer is the most common tumor in women, breast metastases are rare findings. We report the first case in English literature with CRC metastases to the breast and adrenal gland concurrently.

Case presentation

A 42-year-old Caucasian female complained of abdominal pain over the last 3 days. Her history was remarkable for stage 2 colon cancer and she was free of disease for 2 years before the presentation, due to receiving Surgical-chemotherapy. The radiologic investigation showed a well-defined cystic mass in the left adrenal gland and left breast nodule. After adrenalectomy, the diagnosis of the mass was metastatic mucinous adenocarcinoma. During the surgical preparation, bilateral breast lumps were noticed. Histopathology of breast mass showed mucinous adenocarcinoma. Immunohistochemical staining revealed that the neoplastic gland was positive for CDX2, CK20, and P53 mutation and negative for CK7, PR, ER, and HER2. Overall, the diagnosis was metastatic colorectal adenocarcinoma to the breast.

Clinical discussion

Metastatic lesions in the adrenal gland tend to be bilateral with irregular shape. Breast metastases are singular unilateral lesions with predominance in the left breast. Biopsy and immunohistochemistry make the final diagnosis.

The management plan is complex and depends on many factors like the general condition of the patient and the presence of other metastases. However, breast metastases may be a clinical clue to disseminated disease.

Conclusion

Breast metastases should be in the differential diagnosis in patients with a history of colorectal adenocarcinoma, in order to provide the appropriate clinical care.

Breast Metastasis of Gastric Signet Ring Cell Carcinoma: A Case Report and Literature Review

Breast metastasis from gastric signet ring cell carcinoma is extremely rare in clinical practice. The estimated incidence is 0.5-1.3%. There are few cases reported in the literature (approx. less than 60) of breast metastasis from gastric signet ring cell carcinoma, and due to the rare association between gastric cancer and its extension to the breast, it is difficult to establish the diagnosis. Clinical history, histological findings, and immunohistochemical markers are helpful in distinguishing primary breast cancer from breast metastasis of gastric cancer. The treatment for breast metastasis from gastric carcinoma remains controversial. The prognosis of breast metastasis from gastric carcinoma is generally poor. We report a case of breast metastasis of gastric signet ring cell carcinoma in a 38-year-old woman. She started chemotherapy with ramucirumab, paclitaxel, and irinotecan. Three months later, a combined 2-[¹⁸F]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography showed a complete response. This is the first reported case of breast metastasis from gastric signet ring cell carcinoma with a complete response.

Metastatic ovarian cancer spreading into mammary ducts mimicking an in situ component of primary breast cancer: a case report

Background

Accurate diagnosis of metastatic tumors in the breast is crucial because the therapeutic approach is essentially different from primary tumors. A key morphological feature of metastatic tumors is their lack of an in situ carcinoma component. Here, we present a unique case of metastatic ovarian carcinoma spreading into mammary ducts and mimicked an in situ component of primary carcinoma. To our knowledge, this is the second case (and the first adult case) confirming the in situ-mimicking growth pattern of a metastatic tumor using immunohistochemistry.

Case presentation

A 69-year-old Japanese woman was found to have a breast mass with microcalcifications. She had a known history of ovarian mixed serous and endocervical-type mucinous (seromucinous) carcinoma. Needle biopsy specimen of the breast tumor revealed adenocarcinoma displaying an in situ-looking tubular architecture in addition to invasive micropapillary and papillary architectures with psammoma bodies. From these morphological features, metastatic serous carcinoma and invasive micropapillary carcinoma of breast origin were both suspected. In immunohistochemistry, the cancer cells were immunoreactive for WT1, PAX8, and CA125, and negative for GATA3, mammaglobin, and gross cystic disease fluid protein-15. Therefore, the breast tumor was diagnosed to be metastatic ovarian serous carcinoma. The in situ-looking architecture showed the same immunophenotype, but was surrounded by myoepithelium confirmed by immunohistochemistry (e.g. p63, cytokeratin 14, CD10). Thus, the histogenesis of the in situ-like tubular foci was could be explained by the spread of metastatic ovarian cancer cells into existing mammary ducts.

Conclusion

Metastatic tumors may spread into mammary duct units and mimic an in situ carcinoma component of primary breast cancer. This in situ-mimicking growth pattern can be a potential pitfall in establishing a correct diagnosis of metastasis to the breast. A panel of breast-related and extramammary organ/tumor-specific immunohistochemical markers may be helpful in distinguishing metastatic tumors from primary tumors.

Population screening detected non-lymphomatous non-mammary metastases to the breast. A radiology multimodality pictorial essay

This pictorial essay is a presentation of imaging appearances of non-mammary cancer metastases to the breast detected in asymptomatic women attending BreastScreen Western Australia (BSWA) from 2005 to 2019. Haematological malignancies were excluded. Thirteen cases of histologically proven extramammary metastases to breast were identified from the BSWA data base. Five cases were ovarian cancer metastases, 3 melanoma metastases, 2 of adenocarcinoma metastases with foregut primary and one each of endometrial, renal and carcinoid metastases. Metastasis to breast commonly presented as circumscribed masses (N = 12) at mammography and as hypoechoic masses (N = 10) at ultrasound with a predilection to upper outer quadrant of breast. Metastases to breast from non-mammary primary while a rare occurrence in a breast screening program, may be the first clinical presentation of malignancy in asymptomatic women.

Breast Metastases: Updates on Epidemiology and Radiologic Findings

Purpose The aim of this study was to report the prevalence of secondary breast malignancies and analyze their radiological characteristics. Materials and methods We collected 42,505 pathological reports of mammary biopsies performed from January 2000 to January 2019 in our hospital database, from which we screened reports of secondary cancer of the breast. We collected and analyzed imaging data from computed tomography (CT), ultrasound (US), and mammography. Mammograms, CT scans, and US images were reviewed by two breast radiologists. Prevalence of secondary breast malignancy among suspicious breast masses and all breast malignancies were calculated. Results Out of 42,505 histopathology reports from mammary biopsies, we found 19,354 malignancies. We identified 33 cases of secondary breast cancers (0.08% of suspicious breast lesions, 0.17% of breast malignancies). Most common metastases were from lymphoma (23 cases, 0.05% of suspicious breast lesions, 0.12% of breast malignancies) and melanoma (six cases, 0.01% of suspicious breast lesions, 0.03% of breast malignancies). All secondary lesions were hypoechoic on US and showed high density on mammogram. On CT, 83% of the lesions appeared solid/dense, and 17% were mixed, alternating areas of iso/hyperdensity with areas of hypodensity. Conclusion Secondary breast cancer had a prevalence of 0.17% among all breast malignancies. No specific imaging features, characteristic of secondary breast cancer, were found.

Breast metastasis from pelvic high-grade serous adenocarcinoma: a report of two cases

BACKGROUND

Metastatic tumors to the breast reportedly account for 0.5% to 2.0% of all malignant breast diseases. Such metastatic tumors must be differentiated from primary breast cancer. Additionally, few reports have described metastases of gynecological cancers to the breast. We herein report two cases of metastasis of pelvic high-grade serous adenocarcinoma to the breast.

CASE PRESENTATION

The first patient was a 57-year-old woman with a transverse colon obstruction. Colostomy was performed, but the cause of the obstruction was unknown. We found scattered white nodules disseminated throughout the abdominal cavity and intestinal surface. Follow-up contrast-enhanced computed tomography (CT) showed an enhanced nodule outside the right mammary gland. Core needle biopsy (CNB) of the right breast mass was conducted, and immunohistochemical staining of the mass suggested a high-grade serous carcinoma of female genital tract origin. We diagnosed the patient's condition as breast and lymph node metastasis of a high-grade serous carcinoma of the female genital tract. After chemotherapy for stage IVB peritoneal cancer, tumor reduction surgery was performed. The second patient was a 71-year-old woman with a medical history of low anterior resection for rectal cancer at age 49, partial right thyroidectomy for follicular thyroid cancer at age 53, and left lower lung metastasis at age 57. Periodic follow-up CT showed peritoneal dissemination, cancerous peritonitis, and pericardial effusion, and the patient was considered to have a cancer of unknown primary origin. Contrast-enhanced CT showed an enhanced nodule in the left mammary gland with many enhanced nodules and peritoneal thickening in the abdominal cavity. CNB of the left breast mass was conducted, and immunohistochemical staining of the mass suggested a high-grade serous carcinoma of female genital tract origin. After chemotherapy for stage IVB peritoneal cancer, tumor reduction surgery was performed.

CONCLUSIONS

We experienced two rare cases of intramammary metastasis of high-grade serous carcinoma of female genital tract origin. CNB was useful for confirming the histological diagnosis of these cancers that had originated from other organs. A correct diagnosis of such breast tumors is important to ensure quick and appropriate treatment.

Extra-abdominal ovarian cancer presenting with breast metastases at diagnosis: Case report and literature review

OBJECTIVE

Malignant ovarian tumours are diagnosed at an advanced stage in the majority of cases. However, only a small percentage present as extra-abdominal, non-lymph-node solid metastases, as in the breast, and they are usually cases of relapse. The discovery of mono- or bilateral breast lesions with peritoneal carcinosis and/or abdomino-pelvic lesions can be cumbersome in the differential diagnosis of primary tumours. This article aims to summarize current evidence on the detection of breast metastases at diagnosis of ovarian cancer.

STUDY DESIGN

A systematic review of the literature in Scopus, PubMed/MEDLINE, ScienceDirect and the Cochrane Library, including case reports and case series, was undertaken. Data regarding study features; population characteristics; clinical, radiological and histological assessment of the disease; treatment and follow-up were collected. In addition, a case report of a patient managed at the authors' centre is provided.

RESULTS

According to the search strategy, 16 articles (18 patients) were included in this review. Serous ovarian, fallopian tube or primary peritoneal cancer was detected in 61% of cases, while another type or a non-specified type of epithelial ovarian cancer was detected in 27.7% of cases; there was one case with granulosa cell tumour of the ovary and one case with mucinous ovarian tumour of low malignant potential. Breast metastases were mainly monolateral (66.6%), with other extra-abdominal sites of disease in the majority of the cases. A minority of patients (16.6%) received treatment for primary breast cancer with a subsequent diagnosis of ovarian cancer. Concomitant breast and abdominal surgery can be an option. PAX8, WT1 and CA125 immunohistochemical staining can aid in differential diagnosis.

CONCLUSION

Breast metastases of malignant ovarian tumours must be promptly recognized to ensure proper treatment. Specific immunohistochemical analysis can be a decisive assessment in uncertain cases.

Ovarian Cancer Metastasis to the Breast: A Case Report and Review of the Literature

Although ovarian cancer often presents as a widespread disease, metastases to the breast and/or axillary lymph nodes are a very rare event, accounting for only 0.03-0.6% of all breast cancers. Its early recognition and accurate distinction from primary breast cancer are of crucial importance to choose an adequate systemic therapy over unnecessary surgeries. We presented the case of a 53-year-old woman who was diagnosed with breast metastases 2 years after the diagnosis of advanced primary serous ovarian cancer. The patient underwent primary cytoreductive surgery and platinum-based chemotherapy in combination with bevacizumab, followed by bevacizumab maintenance for 18 months. After 2 years of negative follow-ups, the disease unexpectedly spread to the left breast and axillary lymph nodes. No axillary lymph node dissection or breast surgery was performed. The patient received axillary radiotherapy and multiple chemotherapy lines: gemcitabine/cisplatin, liposomal doxorubicin, topotecan, olaparib/cediranib, paclitaxel, and cisplatin. Unfortunately, none of these treatments improved her prognosis and she died 3 years after the disease recurrence. Ovarian cancer metastasis to the breast reveals a disseminated disease with a poor prognosis. Currently, no valid treatment options are available as the disease shows multidrug chemoresistance. In the era of precision medicine, the characterization of genetic and molecular markers may play a role in offering new promising targeted therapies.

Breast and Axillary Lymph Node Metastasis from Ovarian Cancer: A Case Report

BACKGROUND Breast metastasis (BM) is extremely rare. Ovarian cancer accounts for approximately 0.03% to 0.6% of all BMs. BM diagnosis is challenging and the prognosis very poor. The treatment is multidisciplinary and strictly related to multiple clinical and biological factors. CASE REPORT A 70-year-old non-smoking Caucasian woman was hospitalized for a 4-month history of abdominal pain, anorexia, and weight loss of 10 kg. During the clinical examination, we found multiple axillary lymph nodes and a painless tumor lesion in the superior internal quadrant of the right breast. Whole body CT-scan and ¹⁸F-fluorodeoxyglucose PET scan documented a right ovarian tumor associated with multiple metastases, a hypermetabolic lesion of the right breast, and multiple axillary lymphadenopathies that were confirmed by breast ultrasonography. The percutaneous biopsy of both the right axillary lymph node and breast tumor showed a metastasis from a high-grade serous papillary ovarian adenocarcinoma. Considering the tumor aggressiveness and the lack of BRCA1 and BRCA2 mutations, we started systemic chemotherapy with a 3-week carboplatin/paclitaxel regimen combined with bevacizumab, which quickly improved the patient's symptoms and induced a biological tumor response. CONCLUSIONS This case reports a synchronous breast metastasis from an ovarian cancer and highlights this uncommon entity, which is very difficult to diagnose and treat. A differential diagnosis from a primary breast cancer should be considered as the treatment and prognosis of these 2 tumors are different.

Breast Metastasis From a Non-small Cell Lung Cancer: A Case Report

Although primary breast cancer (BC) is the most frequent cancer in the world, their mammary metastases are rare. In this paper, we report the case of a 51-year-old male patient diagnosed with a mammary lump and an intracranial hypertension syndrome. Mammography showed the presence of an irregular opacity without microcalcifications. After a cytological and immunohistochemical examination, the breast biopsy showed an adenocarcinoma of pulmonary origin. Computed tomography (CT) scans of the cerebrum, cervicothoracic spine, and abdomen showed a right apical pulmonary tumor associated with Barety's lymphadenopathy, as well as the presence of a mass in the right breast and secondary brain lesions. The patient received total brain irradiation which resulted in a marked clinical improvement. Afterward, he was treated with six cycles of palliative chemotherapy based on carboplatin area under the curve (AUC) 6 and paclitaxel, 175 mg/m² every 21 days, with a good response. After two months, the patient presented with a progression and he was treated with second-line chemotherapy. However, after three chemotherapy courses, the disease rapidly progressed and the patient was altered which required his admission to the palliative care department. The patient died 40 days later. This case shows the poor prognostic survival outcomes in this population of patients.

High-Grade Endometrioid Carcinoma of the Endometrium With a GATA-3-Positive/PAX8-Negative Immunophenotype Metastatic to the Breast: A Potential Diagnostic Pitfall

This report describes clinicopathologic findings from the case of a patient with a breast mass that was ultimately diagnosed as a metastatic high-grade endometrioid carcinoma of endometrial origin. The breast lesion as well as the solid areas of the endometrial lesion displayed a similar immunoprofile: GATA3-positive; synaptophysin positive; negative for mammaglobin, gross cystic disease fluid protein-15, chromogranin, estrogen receptor, progesterone receptor, and HER2/neu; and intact expression of the DNA mismatch repair proteins MLH1, MSH2, MSH6, and PMS2. The breast lesion was negative for PAX-8, whereas the solid areas of the endometrial lesion showed focal weak positivity. A review of the literature on GATA-3 expression in endometrial carcinomas found a reported frequency of expression that ranged from 0% to 13% of cases, typically in a patchy, focal, and generally restricted pattern. However, GATA-3 may be diffusely expressed in high-grade endometrial carcinomas. Since the potential for PAX-8 expression to be lost in high-grade endometrioid carcinomas is well known, a GATA-3-positive/PAX8-negative immunoprofile may be encountered in high-grade endometrioid carcinomas of the endometrium, and this composite immunoprofile is a potential diagnostic pitfall when such a lesion is being evaluated in a breast metastasis.

Aggregation-Induced Emission Photosensitizers: From Molecular Design to Photodynamic Therapy

Photodynamic therapy (PDT) has emerged as a promising noninvasive treatment option for cancers and other diseases. The key factor that determines the effectiveness of PDT is the photosensitizers (PSs). Upon light irradiation, the PSs would be activated, produce reactive oxygen species (ROS), and induce cell death. One of the challenges is that traditional PSs adopt a large flat disc-like structure, which tend to interact with the adjacent molecules through strong π-π stacking that reduces their ROS generation ability. Aggregation-induced emission (AIE) molecules with a twisted configuration to suppress strong intermolecular interactions represent a new class of PSs for image-guided PDT. In this Miniperspective, we summarize the recent progress on the design rationale of AIE-PSs and the strategies to achieve desirable theranostic applications in cancers. Subsequently, approaches of combining AIE-PS with other imaging and treatment modalities, challenges, and future directions are addressed.

Ovarian cancer metastasis to the breast 18 years after the initial diagnosis: A case report

RATIONALE

Ovarian cancer often metastasizes, but it is unusual to transfer to the breast as an isolated mass. In particular, it is rare for patients to have breast metastases after 18 years of diagnosis of ovarian cancer. Therefore, accurate identification of ovarian cancer mammary gland metastasis can contribute to the treatment of the disease.

PATIENT CONCERNS

This case report shows that an 82-year-old woman was diagnosed with breast metastases from ovarian cancer diagnosed 18 years ago. The patient underwent total uterine attachment, omentum, pelvic lymphadenectomy, pelvic floor tumor reduction, and chemotherapy 18 years ago.

DIAGNOSIS

The pathological examination revealed metastatic adenocarcinoma. Immunohistochemical (IHC) staining results were negative for estrogen receptor (ER), progesterone receptor (PR), human epidermal receptor-2 (Her-2), and thyroid transcription factor-1 (TTF-1); and positive for cytokeratin (CK) 5/6, CK7, and CA125.

INTERVENTIONS

The patient underwent breast-conserving surgery and sentinel lymph node biopsy because of breast mass in November, 2018.

OUTCOMES

Currently, she has been followed for more than 1 month without any signs of recurrence.

LESSONS

Breast metastatic tumors should be distinguished from primary breast tumors to avoid any unnecessary surgery. The correct diagnosis is very important: surgical treatment of patients with secondary breast cancer may be diagnostic and palliative.

Alveolar soft part sarcoma metastatic to the breast: a case report

Background

Alveolar soft part sarcoma (ASPS) is an extremely rare neoplasm that tends to occur in the lower limbs of children and adolescents. Metastatic breast tumors constitute 0.5–2.0% of all malignant mammary neoplasms, and cases of ASPS with mammary metastases are very rare.

Case presentation

Three years ago, an 11-year-old girl presented to the hospital with pain in the right jaw after becoming aware of a mass in the right cheek. After detailed examination, the patient was diagnosed with ASPS with the primary tumor in the right cheek and multiple lung metastases, and chemotherapeutic treatment was initiated. One year later, accumulation of fluorodeoxyglucose (FDG) was observed in the right front of the skull (standardized uptake value (SUV)-max 2.8) and left breast (SUV-max 2.4) using FDG-positron emission tomography (PET) / computed tomography (CT). Ultrasonography revealed the mammary tumor as a hypoechoic, internally heterogeneous mass measuring 22.4 × 16.2 × 21.1 mm with a rich blood supply. Using pathological findings of core-needle biopsy, we diagnosed it as ASPS. Based on the above information, we made a diagnosis of ASPS with left mammary and cranial metastases. Due to chemoresistance, surgical excision was selected as the mode of treatment; resection of the metastatic cranial bone was performed first, and partial mastectomy of the left breast was performed in two stages. Postoperative conditions were good, and we are currently performing regular follow-ups (visual palpation every 3 months and semi-annual mammary gland ultrasonography).

Conclusions

We have reported an extremely rare case of ASPS with mammary metastasis with some reference-based discussion. In our case, disease control was obtained by a combination of drug therapy and surgical treatment.

Metastatic cervical adenocarcinoma to the breast: A case report and literature review

Breast metastases from gynecologic cancers are rare. Cervical cancer most commonly metastasizes to the lung, liver or bone. When cervical cancer metastasizes to the breast, the presentation is usually a solitary breast mass; rarely, however, breast metastases can mimic inflammatory breast cancer. We present a case of metastatic cervical adenocarcinoma presenting clinically as inflammatory breast cancer and review the relevant literature.

Breast metastasis two years after pelvic surgery and adjuvant chemotherapy for serous ovarian cancer

Ovarian cancer is considered the leading cause of death among gynecologic neoplasias. Breast metastases from primary ovarian cancer have been reported in only 0.03-0.6% of all breast cancers. A 38-year-old female, multipara, affected by advanced ovarian cancer and undergone a total abdominal hysterectomy with bilateral salpingo-oophorectomy, omentectomy, and pelvic peritonectomy two years earlier, was discovered to have a breast metastasis. She underwent a quadrantectomy (QSI) with an open biopsy of nodularity attached to the pectoral muscle fascia: on definitive histological characterization the breast lesions showed a high-grade invasive carcinoma, with papillary serum differentiation, and the immunohistochemistry study of breast lesion showed positivity for cytokeratin 7 and an extensive positivity for Wilm's tumor (WT)-1 and paired box 8 (PAX8). These aspects are indicative of mammary metastasis from carcinoma of ovarian origin. Despite their rarity, metastases to breast from ovarian cancer should be considered possible because their recognition and differentiation compared to primary tumors are crucial for prognosis. Future clinical studies on MOCB should be performed to discover new specific markers for a more accurate histopathological diagnosis and to establish the real need of surgical treatment.

Hyperprogression in Pediatric Melanoma Metastatic to the Breast Treated with a Checkpoint Inhibitor

Metastatic melanomas in the pediatric population are rare, but they have been appearing more frequently. Unfortunately, little is known about the differences in the biology and therapeutic implications of pediatric metastatic melanomas when compared to those found in adults. Herein, we have presented the case of a 13-year-old girl with a stage IIID malignant melanoma arising from a congenital nevus. This patient underwent surgical management, and she received adjuvant interferon therapy; however, this treatment was incomplete due to a grade 3 transaminase elevation and the early recurrence of the disease. An isolated metastasis to the breast was documented, and a mastectomy was performed. Soon afterward, low-volume lung metastases developed, and she was treated with nivolumab. After two treatment cycles, the disease continued to develop in a hyperprogressive manner. Advances in the characterization and understanding of pediatric melanomas are needed, as well as experience in the management of new therapies in these cases, which would help clarify the extent to which we can extrapolate the data obtained from the adult population. Therapeutic interventions in melanoma cases are evolving rapidly, and the role of metastasectomies in the era of immunotherapy and BRAF and MEK-targeted therapies is largely unknown. Moreover, the identification of risk factors for the development of hyperprogression and its underlying mechanisms are also warranted.

Gastric cancer with breast metastasis: Clinical features and prognostic factors

Metastatic spread of gastric carcinoma to the breast is rare. In previous decades, reports on this subject were minimal and primarily limited to case reports. At present, little is known on the clinicopathological features and prognosis of this condition, and breast metastasis remains a challenging clinical problem. A total of 54 cases of breast metastasis from gastric cancer were collected from databases between January 1960 and December 2016. The present study included 3 cases of gastric cancer with breast metastasis from Renji hospital and 51 additional cases from previous studies. The clinicopathological features of patients, including epidemiology, symptoms, macroscopic presentation, pathological diagnosis, imaging, treatment and overall survival time, were analyzed. The median survival time was 8.6 months. All but one of the patients were female, and the median age at diagnosis of breast metastasis was 43 years old (age range, 22–72 years). A majority of patients presented with Borrmann class III disease, signet ring cell carcinoma, T4 tumor types, lymph node involvement, initial stage IV gastric cancer, primary lesions in the gastric antrum, left breast metastasis and palpable breast nodules. The median interval between the primary gastric carcinoma diagnosis and presentation of breast metastasis was 1.25 months (range, 0–72 months). The expression of the estrogen receptor, progesterone receptor, human epidermal growth factor receptor-2 and gross cystic disease fluid protein-15 was negative in the patients with breast metastases. In univariate analysis, age, gastric tumor size, gastric lymph node involvement and breast metastasis histology were significantly associated with overall survival (OS) time (P=0.001, 0.039, 0.034 and <0.001, respectively). Therapeutically, gastric surgery and chemotherapy were not associated with OS (P=0.959 and 0.290, respectively). In further multivariate analysis, the time between occurrence (P=0.017), age (P=0.009), histology (P=0.045) and breast metastasis localization (P=0.043) were independent indicators of OS time. Although breast metastasis from gastric cancer is rare, physicians should be vigilant when patients with a history of gastric cancer present with newly developed mammary symptoms and signs.

Breast Metastasis from Gastric Signet Ring Cell Carcinoma, Mimicking Inflammatory Carcinoma. A Case Report

We report a case of breast metastasis of signet ring cell gastric cancer clinically presented as a primary inflammatory carcinoma. Metastases to the breast are uncommon; review of the literature demonstrated only 300 cases. The clinical and radiographic features of the metastatic lesion were unlike those reported in the literature. Although a primary signet ring cell breast carcinoma was described, the pathologic patterns of the breast lesion, here reported, lead us to conclude this was a metastasis and not another primary tumor.

Squamous Cell Carcinoma of the Breast Diagnosis by Vacuum-assisted Core Biopsy

Squamous cell breast carcinoma is a rare occurrence. Often the tumor is metastatic from an extramammary primary tumor. In order to determine the nature of the lesion, extensive sampling is necessary. We report a case of primary squamous cell carcinoma of the breast diagnosed by vacuum-assisted core biopsy.

Breast Metastases from Cutaneous Melanoma a Report of Three Cases

In this report we describe three female patients with breast metastases from cutaneous melanoma (CM) who were treated in Slovenia in the period from 1988 to 1991. We found that in 476 Slovenian patients with this disease diagnosed in the given period CM disseminated to the breast less frequently than in other series. In one pregnant and one perimenopausal patient breast involvement by CM was confirmed at the time of widespread dissemination of the disease. Treatment was not effective and the survival of these patients was four months and two weeks and six months, respectively. A slightly better outcome was observed in a normally menstruating patient referred from another country with an isolated solitary breast metastasis from CM. In this patient quadrantectomy seemed to have been sufficient to achieve a disease-free interval of more than eight months. Special attention should therefore be given to a small subset of patients with isolated solitary breast metastases from CM, since their prognosis may be less dismal than in patients with massively infiltrated breasts and disseminated disease.

[Imaging diagnostics of breast metastases from extramammary tumors]

Breast metastases of solid extramammary tumors are very rare in comparison to primary malignancies of the breast and account for only 0.33-6.3% of all malignant neoplasms of the breast. The most common primary tumors are malignant melanoma, distant sarcomas, lung cancer, ovarian cancer, renal cell cancer and thyroid cancer in decreasing order of frequency. This review article summarizes the clinical features and the different imaging findings of breast metastases from different extramammary solid tumors. Breast metastases are often incidental findings in computed tomography (CT) or positron emission tomography CT (PET-CT) imaging. Mammography shows two different imaging patterns, namely focal lesions and diffuse architectural distortion with skin thickening. Breast metastases presenting as focal masses usually occur as solitary and more rarely as multiple round lesions with a smooth edge boundary. Associated calcifications are rare findings. Diffuse architectural distortion with skin thickening is more common in breast metastases from most gastric tumors, ovarian cancer and rhabdomyosarcoma. Using ultrasound most lesions are hypoechoic, oval or round with smooth boundaries and posterior acoustic enhancement. The magnetic resonance imaging (MRI) criteria of breast metastases show an inconstant signal behavior that cannot be safely classified as benign or malignant. In summary, in patients with known malignancies the presence of breast metastases should be considered even with imposing clinically and radiologically benign findings.

Isolated metachronous breast metastasis from renal cell carcinoma: A report of two cases

Metastases to the breast are very uncommon as compared to primary tumours. Breast is an unusual site for metastasis from renal cell carcinoma. Only occasional cases are reported in the literature. These metastases must be clearly diagnosed as the treatment of primary breast cancer and metastases differs markedly. Treatment of isolated metastases from renal cell carcinoma is usually surgical resection. We report two cases of isolated metachronous metastases to breast from renal cell carcinoma.

Characteristics of breast metastases from non-breast solid tumors in 22 patients from a southern Chinese population

Breast metastases from solid non-breast tumor types are rare; however, they should be always considered in the differential diagnosis of a breast lesion owing to the associated poor patient prognosis and the requirement of different therapeutic strategies compared with those used to treat primary breast cancer. The aim of the current study was to summarize the characteristics of metastases to the breast in a southern Chinese population. The medical records and pathological sections of 22 patients with pathologically confirmed extra-mammary metastases to the breast that presented to Sun Yat-sen University Cancer Center between January 2000 and December 2015 were retrospectively reviewed. The median age of onset for breast metastasis was 43 years (range, 10-62 years) and 19 (86.4%) patients had a known history of a primary tumor. The mean interval from diagnosis of the primary tumor to breast metastasis was 16.5 months (range, 6-56 months). A unilateral (45.5% left, 36.4% right), upper outer quadrant (15/22, 68.2%) lesion of the breast was most frequently initially detected by self-checking (63.6%). The most common origin of the primary tumor was the lung (22.7%). Nasopharyngeal carcinoma accounted for a high proportion of the metastases (18.2%). The median duration of survival from the time of diagnosis of a breast metastasis was 14 months (range, 2-74 months). A total of 10 patients (45.5%) succumbed to the disease. The results also indicated that overall survival in patients that underwent surgery was improved compared with patients who did not undergo surgery. The results of the present study demonstrated that clinical history, imaging findings, pathology from the primary tumor and immunostaining were required in combination to establish an accurate diagnosis. Further investigation into the improvement of the prognosis of patients with metastases to the breast following surgery is required.

Isolated breast metastasis from gastric cancer in a male patient

A 72-year-old man underwent total gastrectomy for gastric cancer (por2, T3, N2, Stage IIIA). Eleven courses of postoperative chemotherapy with TS-1 (tegafur/gimeracil/oteracil) were administered. Five months after surgery, the serum carcinoembryonic antigen value was slightly elevated. However, computed tomography did not reveal any metastatic lesions in other organs. Two years after surgery, the patient felt a mass in the left mammary. A 2-cm tumor was palpable in the central portion of the breast. Ultrasonography revealed a hypoechoic tumor, which was Class 3 on aspiration biopsy cytological examination. No mass was detected on positron emission tomography-computed tomography. The mammary gland tumor increased in size to 3 cm, and a core needle biopsy procedure was performed. Histological examination findings revealed breast metastasis of gastric cancer. No other recurrence was found, and radical mastectomy was performed 2 years and 5 months after gastrectomy. Immunohistological analysis of the resected material confirmed breast metastasis of the gastric cancer. Two courses of TS-1 + cisplatin were administered, but this treatment was subsequently terminated because the patient experienced Grade 3 diarrhea and neutropenia. Three years and 1 month after the gastrectomy, the tumor recurred in the pelvic area. Chemotherapy and radiation therapy were performed, but the patient's overall condition became progressively worse, and he died 3 years and 9 months after gastrectomy.

Breast metastasis from squamous cell carcinoma of the oropharynx: a case report

Background

Breast metastases from extramammary tumors are extremely rare, the most common primary tumors being contralateral breast carcinoma, followed by lung, gynecological, gastrointestinal, melanoma, and hematological cancers. Only a few cases deriving from head and neck squamous cell carcinoma have been reported in the literature to date.

Case presentation

We report a case of a 47-year-old Caucasian woman who presented to our hospital with a solitary breast lesion in the right upper external quadrant associated with multiple bone and visceral metastases. Two years before, she had undergone radical resection of a squamous cell carcinoma of the oropharynx (stage pT2, pN1), which was followed by adjuvant radiotherapy. Breast ultrasound showed a hypoechogenic tumor lesion of 4 cm in the right upper external quadrant that was associated with multiple axillary and infra-/supraclavicular adenopathies. A positron emission tomographic scan documented multiple visceral and bone metastases with a single hypermetabolic lesion of the right breast. The results of histology and immunohistochemistry were consistent with a metastasis from a squamous cell carcinoma. The patient died of acute respiratory insufficiency 1 month after her breast metastasis diagnosis and before starting any systemic antitumoral treatment.

Conclusions

Although breast metastases are extremely rare, they should be considered in any patient with a history of cancer and confirmed by histology and immunohistochemistry because they are very difficult to distinguish from other primary breast tumors based only on clinical and radiological features. There are no standardized treatment guidelines for breast metastasis management. Surgery and radiotherapy can play a role in symptom palliation, but they do not have any relevant impact on survival, the prognosis being poor, with an estimated overall survival less than 1 year from diagnosis.

Metastatic non-small cell lung carcinoma a mimic of primary breast carcinoma-case series and literature review

Metastatic tumors to the breast are rare but constitute a major diagnostic dilemma. Of these, non-mammary carcinomatous metastases to the breast are particularly challenging and, without a clinical history, may be extremely difficult to distinguish from primary breast carcinoma (PBC). We specifically studied metastatic tumors of pulmonary origin, as the lung is one of the major primary sites for carcinomatous metastasis to breast. Sixteen metastatic lung tumors to the breast were identified in our archives between 1996 and 2017 including 12 non-small cell lung carcinomas (NSCLC), one large-cell neuroendocrine, one atypical carcinoid, and two small-cell carcinomas. Adenocarcinoma was the most frequent amongst the NSCLCs (11/14). We retrieved the clinical information of these cases and reviewed the pathological characteristics to provide practical tools for pathologists to aid in their identification. Even in the absence of a clinical history of lung cancer, metastatic pulmonary adenocarcinoma to the breast should be considered in at least one of the following scenarios: (1) single or multiple well-circumscribed lesions of the breast that lack an in situ component and that are accompanied by distant metastases but negative axillary lymph nodes, (2) breast tumors that are triple negative yet not high-grade, or (3) breast tumors presenting as stage 4 disease and/or having an unusually aggressive clinical course on standard breast therapy. Accurate and timely diagnosis of these tumors is mandatory because of treatment and prognostic implications.

Metastases of transverse colon cancer to bilateral ovaries (Krukenberg tumor) and the left breast: A case report

Breast cancer has the highest rate of incidence among all types of cancer in women. Only ~0.43% of breast malignancies occur as a result of metastatic lesions from extramammary tumors. The present study reports an extremely rare case of transverse colon cancer metastasizing to the bilateral ovaries and the left breast. The patient was a 47-year old female, who had a lump in the left breast without axillary lymphadenopathy. Specimens obtained by core needle biopsy were submitted for hematoxylin and eosin examination, and results revealed that the lump was a poorly differentiated adenocarcinoma. Since the patient had elevated levels of the carcinoembryonic antigen and a medical history of a Krukenberg tumor metastasized from colon cancer, immunohistochemical examinations were applied. Results identified that caudal-related homeobox protein 2 and cytokeratin 20 were positively stained, whilst cytokeratin 7 was negatively stained. Therefore, this patient was diagnosed as having colon cancer that had metastasized to the bilateral ovaries and the left breast. As the life expectancy of patients with cancer is increasing, types of metastases that used to be seen as rare are increasingly becoming more common. For clinicians, diagnosis should be cautious, and differential diagnosis should always be kept in mind.

Merkel cell carcinoma, melanoma, metastatic mimics of breast cancer

Merkel cell carcinoma and melanoma can each occur primarily in breast skin, or metastasize to the breast. The breast is a rare site of metastasis of essentially any and every type of tumor, including carcinomas, sarcomas, and hematolymphoid neoplasms, and 10-30% of breast metastases may represent the initial presentation of disease. Although metastases generally recapitulate histologic features of the primary tumor, they are diagnostically challenging given their rarity and morphologic overlap with breast carcinoma, including special types of breast cancer. Histologic clues may include lack of carcinoma in situ, lack of central elastosis, pattern of infiltration around normal breast structures, yet none of these are specific. Careful correlation with clinical history and judicious use of immunostain panels is essential in approaching these cases.