|Ahead of print publication
Primary ectopic breast carcinoma arising in the inguinal region in a male patient
Vivek Y Bansal1, Varun V Bansal2, Shakuntala V Shah3, Akash R Bellige1
1 Department of Radiation Oncology, CBCC Apollo Hospital, Gandhinagar, Gujarat, India
2 Undergraduate Medical Student, Seth G.S. Medical College and KEM Hospital, Mumbai, Maharashtra, India
3 Department of Surgical Oncology, Apollo Hospital, Gandhinagar, Gujarat, India
|Date of Submission||13-Jun-2020|
|Date of Decision||13-Aug-2020|
|Date of Acceptance||24-Nov-2020|
|Date of Web Publication||15-Jun-2022|
Vivek Y Bansal,
1st Floor, Department of Radiation Oncology, CBCC Apollo Hospital, Gandhinagar - 382 428, Gujarat
Source of Support: None, Conflict of Interest: None
Carcinoma arising in ectopic breast tissue is a rare entity, especially in males, in whom the diagnosis is often delayed due to a low index of suspicion. Conventional imaging techniques fail to characterize the tumor, adding further to the diagnostic dilemma. We report the first case in our knowledge of an extramammary primary breast carcinoma arising in the inguinal region in a male. Our patient, a 69-year-old male, presented with a swelling in the left inguinal region, which was excised and diagnosed as luminal A type invasive ductal carcinoma. He received adjuvant external beam radiotherapy (50 Gy administered in 25 fractions) and tamoxifen. A follow-up examination performed 6 months after the completion of the last dose of radiotherapy showed no residual disease. The modalities of treatment for such tumors have been discussed, with emphasis on surgery and radiotherapy, given the aggressive nature of the disease.
Keywords: Ectopic breast tissue, inguinal region, male breast cancer, mammary line, radiotherapy
| > Introduction|| |
Accessory mammary glands, also known as ectopic breast tissue, develop along the milk lines when primordial breast tissue located along these lines fail to degenerate. Although glandular diseases may occur in accessory mammary glands, malignant tumors rarely develop in them, especially in male patients. Therefore, there is a shortage of experience in the diagnosis and treatment of accessory breast malignancies in males. To our knowledge, this is the first case of primary breast carcinoma arising in the inguinal region in a male.
| > Case Report|| |
Our patient, a 69-year-old male, presented with a painless swelling of 10-month duration in the left inguinal region, which measured 3 cm × 4 cm and was hard on palpation. Ultrasonography (USG) revealed a well-defined anechoic lesion located within the skin and subcutaneous tissue with increased vascularity on color Doppler. The soft-tissue swelling was excised and sent for histopathological examination, which revealed a poorly differentiated carcinoma extending up to the surgical margins with the presence of lymphovascular emboli and perineural invasion [Figure 1] and [Figure 2]. Immunohistochemistry revealed cells expressing CK-7, GATA-3, synaptophysin, chromogranin A, ER (80%), and PR (80%), and was negative for HER 2/NEU and other markers. The MIB labeling index (Ki-67-specific monoclonal antibody) was approximately 10%. An interpretation of adnexal adenocarcinoma resembling a breast carcinoma was made considering the location of the swelling along the distal part of the milk line. A positron emission tomography–computed tomography (PET-CT) scan performed postoperatively was negative for hypermetabolic lesions in the operated bed as well as at other sites. There was no palpable lump in the chest region.
|Figure 1: A dermal infiltrate of tumor cells in small nests is seen at ×10 magnification (hematoxylin and eosin stain)|
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|Figure 2: Tumor cells in small nests with uniform round-oval nuclei, fine chromatin, and pale eosinophilic cytoplasm are seen at ×40 magnification (hematoxylin and eosin stain)|
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The patient was referred to an oncosurgeon, who performed a revision wide local excision along with dissection of three adjoining lymph nodes. Histopathological examination revealed a residual 5 mm focus of malignant epithelial cells. However, the deep resection margins were free. Lymphovascular and perineural invasions were absent. All three nodes were negative for metastases. Immunohistochemistry revealed a pattern of ER, PR, and HER-2/NEU expression similar to the previous test. A diagnosis of luminal A type invasive ductal carcinoma arising in ectopic breast tissue was made, following which adjuvant therapy with tamoxifen (20 mg/day) was started.
The patient was then referred to our hospital where a multidisciplinary team evaluated the case. Considering the aggressive nature of the disease, as suggested by a thorough review of the existing literature, adjuvant external beam radiotherapy was recommended. Three-dimensional conformal radiation treatment was carried out, during which a dose of 50 Gy was administered in 25 fractions over 5 weeks. The patient tolerated the treatment well with minimal pigmentation over the irradiated area and no edema over the left inferior extremity.
A follow-up PET-CT examination after 6 months revealed no residual disease locally and did not reveal any new lesions at other sites in the body.
| > Discussion|| |
Ectopic breast cancer is a rare entity with an incidence of <1%, occurring predominantly in females. The low index of suspicion in males often leads to a delay in diagnosis and recognition at advanced stages with poor prognosis. A case of ectopic breast carcinoma in the inguinal region of a female patient has been reported by Loh et al., but such a case has not been reported yet in a male.
The exact etiology of the development of malignancy in such ectopic mammary glands is not known. However, genetic and environmental risk factors for breast cancer in the orthotopic mammary gland may play a role in the pathogenesis. The axilla is the most common site of occurrence of ectopic breast cancer in both males and females. Other locations that have been reported commonly in the past include the abdominal wall and the vulva. Invasive ductal carcinoma is the most common histological subtype of ectopic breast cancer, and the cells commonly express tissue markers associated with orthotopic breast cancer.
A palpable lump with or without tenderness and skin changes such as erythema and ulceration are the common presenting symptoms of ectopic breast cancer., The imaging modalities such as USG, CT, and magnetic resonance imaging do not have a role in confirming the diagnosis of ectopic breast cancer but may help in deciding the further line of management by assessing the involvement of adjacent structures and lymph nodes. A PET-CT scan can locate the primary tumor, distant metastases, and any residual disease after treatment. A definitive diagnosis can only be made after histopathological examination with immunohistochemical testing for breast-derived markers.
There are no standardized protocols for the management of ectopic breast cancer considering the rarity of the disease. The treatment is similar to that of conventional breast cancer, with surgical excision being the mainstay of treatment which can be supported by adjuvant radiotherapy, hormonal therapy, and/or chemotherapy. The complications that follow axillary lymph node dissection for breast carcinoma such as lymphedema and restriction of limb movement were not relevant in our case. Furthermore, sentinel node biopsy was not applicable as the sensitivity of dye pickup in the inguinal region is poor. Minimal seroma collection was the only complication that occurred after inguinal node dissection which resolved by itself.
We avoided chemotherapy considering the geriatric age of our patient and revision surgery showing negative margins on histopathology. We started our patient on tablet tamoxifen given the hormone receptor-positive status and its preference over aromatase inhibitors in males.
Ectopic breast cancer is an aggressive disease, with greater nodal positivity as compared to conventional breast cancer at an equivalent stage and a tendency to recur after excision alone. It also has a propensity to metastasize to bones and the brain.,, Considering these factors, adjuvant radiotherapy is recommended to reduce the risk of recurrence. In our case, we decided to irradiate the tumor bed postoperatively for the same reason.
| > Conclusion|| |
Although rare, accessory breast carcinoma should be considered as a possible diagnosis for an inguinal mass arising in males. Considering the paucity of cases and the absence of clear guidelines, the management of these cases poses a therapeutic challenge. Surgical excision with lymph node dissection followed by adjuvant radiotherapy and tamoxifen (with or without chemotherapy) may be considered for the treatment of accessory breast carcinomas as they seem to be aggressive biologically.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]