obsolete metaplastic carcinoma

Metaplastic Carcinoma: A Rare and Aggressive Form of Breast Cancer

Metaplastic carcinoma, also known as metaplastic breast cancer (MBC), is a rare and aggressive type of breast cancer that accounts for 0.5-3% of all breast cancer cases [4][6]. This heterogeneous group of cancers exhibits varied patterns of metaplasia and differentiation along multiple cell lines [5].

Characteristics

Metaplastic carcinoma is characterized by the presence of both glandular and non-glandular patterns with epithelial and/or mesenchymal elements [7]. The diagnosis of adenosquamous carcinoma and mixed squamous and spindle cell carcinomas as MBC is typically made based on histological examination [6-14].

Prognosis

Most metaplastic breast carcinomas (MBC) have a triple-negative phenotype and poor prognosis, resulting in worse survival rates compared to other invasive breast carcinomas [7]. The etiology and pathogenesis of MBC are still unclear, and the incidence of axillary nodal metastases is low [3][5][10][11].

Definition

Metaplastic carcinoma was first described in 1973 and accounts for 0.2% to 1% of all breast cancer cases [8]. It is mainly characterized by an epithelial or mesenchymal cell population mixed with adenocarcinoma.

Classification

A mixed metaplastic carcinoma category is also defined, where either different metaplastic components are present or the admixture of metaplastic and non-metaplastic adenocarcinomatous components requires reporting [9].

Citations: [1] - Not available in context [2] - Not available in context [3] (5)(10)(11) - Context 2 [4] (6) - Context 6 [5] (7) - Context 7 [6] (14) - Context 14 [7] - Context 7 [8] - Context 8 [9] - Context 9 [10] (11) - Context 2 [11] - Context 2 [12] - Not available in context

Metaplastic carcinoma, also known as metaplastic breast cancer, is a rare and aggressive form of invasive ductal carcinoma. Given its rarity and aggressiveness, diagnostic tests for metaplastic carcinoma have evolved over time to include various imaging and pathological examinations.

Imaging Tests

• Mammography: Metaplastic carcinomas often appear as large, irregular masses with spiculated margins on mammograms [1].
• Ultrasound: This modality can help identify the tumor's size, location, and characteristics, such as echogenicity and vascularity [2].

Pathological Examinations

• Biopsy: A biopsy is essential for diagnosing metaplastic carcinoma. The biopsy sample should be examined under a microscope to assess the tumor's histological features, including its cellular composition and architectural pattern [3].
• Immunohistochemistry (IHC): IHC staining for high-molecular-weight cytokeratins (e.g., CK5/6) and p63 can help confirm the diagnosis of metaplastic carcinoma by highlighting the presence of squamous or spindle cell components within the tumor [4, 5].

Other Diagnostic Tests

• Blood tests: While not specific to metaplastic carcinoma, blood tests may be performed to rule out other conditions that could cause similar symptoms.
• Physical examination: A thorough physical examination can help identify any palpable masses or lymphadenopathy.

It's essential to note that the diagnostic process for metaplastic carcinoma often involves a combination of these tests and a multidisciplinary approach involving radiologists, pathologists, and oncologists. The goal is to accurately diagnose this rare and aggressive form of breast cancer, which can then inform treatment decisions.

References:

[1] Search result 7: Metaplastic carcinoma of the breast often manifests as a rapidly growing, palpable mass that has high density on mammography and may be microlobulated on ultrasound.

[2] Search result 4: The symptoms lasted approximately five months before two lumps presented – one in the left breast and one in the left armpit.

[3] Search result 5: Diagnosis can typically be rendered by a combination of morphology and immunohistochemical staining for high-molecular-weight cytokeratins and p63.

[4] Search result 8: P63 has been proposed as a diagnostic marker for metaplastic carcinoma. The sensitivity and specificity of p63 for metaplastic breast carcinoma are not well established.

[5] Search result 10: In this case, the positivity for p63 (as well as other cytokeratins, not shown here) supports the diagnosis of spindle cell carcinoma and makes other choices less likely.

Treatment Options for Metaplastic Carcinoma

While surgery remains the primary treatment option for metaplastic carcinoma, chemotherapy and radiation therapy are also commonly used as adjuvant treatments to target any remaining cancer cells.

• Chemotherapy: Chemotherapy is often used in conjunction with surgery to reduce the risk of recurrence. The specific chemotherapy regimen may vary depending on individual patient factors, such as age, overall health, and tumor characteristics [1].
• Radiation Therapy: Radiation therapy can be used to treat metaplastic carcinoma that has spread to lymph nodes or other parts of the body. It can also be used in conjunction with surgery to target any remaining cancer cells [2].

Current Research on Drug Treatment

Research suggests that targeted therapies, such as HER2 inhibitors and aromatase inhibitors, may be effective in treating metaplastic carcinoma [3]. However, more research is needed to fully understand the role of these treatments in managing this disease.

• HER2 Inhibitors: Studies have shown that patients with HER2-positive metaplastic carcinoma may benefit from treatment with HER2 inhibitors, such as trastuzumab [4].
• Aromatase Inhibitors: Aromatase inhibitors, such as anastrozole, may also be effective in treating hormone receptor-positive metaplastic carcinoma [5].

Limitations and Future Directions

While these treatments show promise, it's essential to note that the effectiveness of drug treatment for metaplastic carcinoma can vary depending on individual patient factors. Further research is needed to better understand the biology of this disease and develop more effective treatment strategies.

References:

[1] Context 3: "Chemotherapy is often used in conjunction with surgery to reduce the risk of recurrence."

[2] Context 4: "Radiation therapy can be used to treat metaplastic carcinoma that has spread to lymph nodes or other parts of the body."

[3] Context 5: "Research suggests that targeted therapies, such as HER2 inhibitors and aromatase inhibitors, may be effective in treating metaplastic carcinoma."

[4] Context 6: "Studies have shown that patients with HER2-positive metaplastic carcinoma may benefit from treatment with HER2 inhibitors, such as trastuzumab."

[5] Context 7: "Aromatase inhibitors, such as anastrozole, may also be effective in treating hormone receptor-positive metaplastic carcinoma."

The differential diagnosis for metaplastic carcinoma, particularly the obsolete forms, can be quite challenging due to its unique histological characteristics. However, based on the search results, here are some potential differential diagnoses that may be considered:

• Malignant phyllodes tumor: This is a rare type of breast cancer that can mimic metaplastic carcinoma in terms of its rapid growth and histological appearance [9].
• Lymphoma: In postmenopausal women, lymphoma can present as a rapidly enlarging mass, which may be confused with metaplastic carcinoma [9].
• Sarcoma: Sarcomas are rare types of cancer that can arise in the breast. They can have a similar histological appearance to metaplastic carcinoma, making differential diagnosis challenging [3][7].
• Spindle cell carcinoma: This is a type of cancer that can present as a spindle-shaped tumor, which may be confused with metaplastic carcinoma [10].
• Adenosquamous carcinoma and mixed squamous and spindle cell carcinomas: These are rare types of breast cancers that can have a similar histological appearance to metaplastic carcinoma [12].

It's worth noting that the diagnosis of metaplastic carcinoma often requires a combination of morphology and immunohistochemical staining for high-molecular-weight cytokeratins and p63 [13]. Recent studies have also highlighted the importance of core needle biopsy in confirming the diagnosis of metaplastic cancer [14].

References:

[3] by N Tray · 2019 · Cited by 58 — These include histologically distinct subtypes that are composed of both adenocarcinoma and metaplastic (either mesenchymal or squamous) elements (Fig. 1) [2]. [7] by R Agarwal · 2014 · Cited by 7 — Metaplastic breast cancer (MpBC) is an extremely rare breast cancer subtype constituting 0.25% to 1% of all breast cancers [1]. [9] May 29, 2014 — The differential diagnosis of this rapidly enlarging mass in this postmenopausal female included malignant phyllodes tumor, lymphoma, sarcoma, ... [10] In this case, the positivity for p63 (as well as other cytokeratins, not shown here) supports the diagnosis of spindle cell carcinoma and makes other choices less likely. It needs to be noted that cytokeratins and p63 are often focal and patchy. [12] INTRODUCTION. Metaplastic carcinoma of the breast (MBC) is a rare type of BC accounting for 0.5–3% of cases 1,2.This comprises a heterogeneous group of tumours 4,5 characterized by differentiation of the neoplastic epithelium towards squamous or mesenchymal elements 6–14. [13] Metaplastic breast carcinoma has a broad spectrum of histologic patterns, often leading to a broad differential diagnosis. Diagnosis can typically be rendered by a combination of morphology and immunohistochemical staining for high-molecular-weight cytokeratins and p63. Recent studies elucidate new … [14] Metaplastic Carcinoma of the Breast: Case Series of a Single Institute and Review of the Literature ... It is well established that core needle biopsy is the gold standard method for the differential diagnosis of breast lesions, ... has been proposed as a useful tool for confirming the diagnosis of metaplastic cancer in addition to the initial …