One extremely uncommon morphologic kind of female invasive breast cancer is apocrine carcinoma. The range of its incidence is 0.5 to four percent. The use of FNAC as the principal screening method for breast lumps has grown in popularity because of its high level of sensitivity and specificity. However, unusual apocrine cells might be challenging to diagnose. Breast tumors ranging from tiny cysts to malignant carcinomas can exhibit apocrine alterations. Apocrine carcinoma must be differentiated from benign apocrine lesions and granular cell tumors before surgery. Atypical apocrine adenosis, apocrine adenoma, granular apocrine metaplasia, and degenerative cysts are benign apocrine lesions showing low cellularity in FNAC smears. These lesions are made up of cells arranged in flat, regular sheets.
What Is Apocrine Carcinoma?
Breast-invasive apocrine carcinomas are uncommon. The high sensitivity and specificity of Fine Needle Aspiration Cytology (FNAC) have made it a popular primary screening method for breast masses. Apocrine carcinoma must be identified preoperatively from other eosinophilic and granular cell cancers, as well as benign apocrine lesions. Apocrine morphology can be found in various breast carcinomas, including ductal, lobular, mucinous, tubular, and medullary. The term "apocrine carcinoma" refers to breast carcinomas in which the majority of tumor cells have an apocrine morphology, which includes copious packed eosinophilic cytoplasm with granularity or vacuoles, enlarged nuclei, and conspicuous nucleoli. They make up approximately one percent of all breast carcinomas. The clinical characteristics, mammographic appearance, and prognosis of apocrine and non-apocrine ductal carcinomas are virtually identical.
What Are the Signs of Apocrine Carcinoma?
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Apocrine cancer often manifests as a solitary, painless lump that gradually enlarges and can have a range of colors.
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Sweat gland carcinoma is a type of cancer. Apocrine carcinomas can occur on the scalp or other regions of the body. However, they typically appear under the arm (axilla).
What Are the Clinical Features of Apocrine Carcinoma?
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Patients with apocrine cancer can range in age from 19 to 92 years old, with a reported mean age of 53 to 62.
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Strict morphologic criteria reveal that apocrine carcinoma is uncommon, accounting for less than one percent of all cases of breast cancer.
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On the other hand, up to 60 percent of invasive ductal carcinoma NOS have been observed to have focal apocrine differentiation, which is a pretty typical occurrence.
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Apocrine carcinoma shares similarities with invasive ductal carcinoma NOS in terms of both clinical presentation and radiographic features.
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It is an uncommon breast cancer that mostly affects elderly adults.
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It might have an alternative steroid metabolism route.
What Are the Pathological Features?
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Aspirate cells.
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Pleomorphic cell populations with a profusion of granular cytoplasm.
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Big nuclei and noticeable nucleoli in a marked anisonucleosis.
Apocrine differentiation of ductal cells is a characteristic of apocrine carcinomas. Within the mammary gland, typical apocrine cells come in two varieties. Apocrine cells of type B have a large amount of foamy cytoplasm filled with tiny vacuoles, whereas cells of type A have eosinophilic granular cytoplasm. These apocrine cells can multiply into malignant or atypical lesions. In situ disease, invasive ductal carcinoma, and invasive lobular carcinomas can all exhibit apocrine characteristics. Just one percent to two percent of breast cancers are pure apocrine carcinomas, which are extremely uncommon. Their development patterns and clinical characteristics are comparable to invasive ductal carcinoma.
Apocrine carcinoma differs from other types of cancer in that its cells feature finely empty vacuoles in the cytoplasm or an abundance of granular eosinophilia. It resembles other invasive breast carcinomas. Neoplastic cells appear microscopically as sheets, cords, and, in certain cases, tubules. The key characteristics are substantial volumes of eosinophilic, granular cytoplasm, tumor cells with well-defined borders, and big vesicular nuclei. The nucleus-to-cytoplasm ratio is approximately 1:2. They commonly display snouts and accumulations of produced granules in the apical cytoplasm that are easily visible when stained with dyes.
What Is the Cytomorphology of Apocrine Carcinoma?
Apocrine carcinoma's cytomorphology:
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In general, specimens with hypercellularity.
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Solitary cells are arranged in sheets and clusters.
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A lot of granular cytoplasm with hazy cell boundaries.
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A larger, unevenly shaped nucleus.
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A noticeable, sizable nucleolus.
What Are the Differential Diagnosis of Apocrine Carcinoma?
Distinctive Diagnosis:
- Apocrine Cells That Are Hyperplastic or Metaplastic: They have proliferating epithelial cells around them; hyperchromasia and anisonucleosis are not present in large amounts.
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Secretory Carcinoma: Signet-ring development, cytoplasmic vacuoles, and neoplastic cells with noticeable intracellular gaps.
Lipid-rich cancer is characterized by abundant multi-vacuolated cells, a more homogeneous nuclear appearance, and the absence of numerous nucleoli. It is important to differentiate between abnormal changes observed in proliferative and metaplastic apocrine cells and apocrine carcinomas. The accompanying polymorphous cell population, frequently observed in proliferative breast disease, provides information. Atypical apocrine lesions also exhibit substantial hyperchromasia and the absence of anisonucleosis. Lipid-rich and secretory carcinomas are two additional lesions in the differential diagnosis.
What Is the Diagnosis of Apocrine Carcinoma?
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Apocrine carcinomas are still often diagnosed based on their morphologic characteristics in light of the latest guidelines for the WHO Classification of Breast Tumors.
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Practicing pathologists implement a new diagnostic method integrating the distinctive apocrine morphology with a steroid receptor profile. This strategy will lead to a more accurate diagnosis, more consistent reporting of apocrine carcinomas, and, ultimately, a more thorough clinical description of this unusual breast cancer.
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As apocrine carcinoma shares some appearance with other, much rarer neoplasms, such as oncocytic carcinomas, diagnosing it can occasionally be difficult. However, combining morphology and particular immunohistochemistry biomarkers (for example, mitochondrial stains) can be useful in such challenging circumstances.
What Is the Treatment?
Treatment-wise, apocrine carcinoma patients have been shown in some trials to respond poorly to chemotherapy, while HER2-enriched breast carcinomas often have the highest rate of complete response to neoadjuvant chemotherapy.
Conclusion:
Apocrine carcinoma of the breast is an uncommon kind of invasive cancer for which there is currently no specific treatment. Immunohistochemical data can be used to determine the appropriate course of treatment. Patient data indicates that neoadjuvant targeted therapy is appropriate and can produce desirable outcomes for HER2-positive locally advanced apocrine carcinomas of the breast. It is unknown how predictive AR expression is and how effective anti-AR medication is in treating breast cancer. Additional clinical data is required.
Triple-negative apocrine carcinoma is a very rare tumor that should be evaluated in the differential diagnosis of breast lesions based on comprehensive clinical, histological, and immunohistochemical correlations.
