Abstract
BACKGROUND:
Late occurrence of solitary soft tissue upper extremity metastasis of breast cancer is very rare. We hereby present a case of metastasis to the biceps muscle of the ipsilateral arm, detected by a physiotherapist six years after mastectomy. The aim of this report is to highlight the rarity of this presentation, to emphasize the role of the physiotherapist as a member of the multidisciplinary treatment team and the possibility of curative treatment despite the poor prognosis.
CASE DESCRIPTION:
A 2 * 3 cm well-defined isolated metastasis of breast cancer was diagnosed in the left arm of a 31-year-old woman 6 years after successful treatment of her primary tumor. Tumor characteristics, diagnostic plan, and treatment options are discussed.
CONCLUSION:
Due to its scarcity, there is a lack of knowledge about the frequency, interval, characteristics, best diagnostic modality, adequate treatment, and prognosis of isolated breast cancer metastasis to the soft tissue, and these can be found out by proper reporting. As an important member of the multidisciplinary team in the care and treatment of breast cancer patients, physiotherapists should be aware of this type of rare presentation.
Introduction
The prevalence of skeletal muscle metastasis (SMM) from all cancer types is rare and it has been reported from 0.03–17.5% [1]. The most commonly reported primary site of malignancy metastasizing to the soft tissue is the lung, followed by the kidney and the colon [1, 2].
In vitro and in vivo evidence show different mech-anisms that explain scarcity of the soft tissue metastases, including production of a low molecular weight factor, anti-cancer factors, and natural agonists of adenosine receptors by muscles cells, which can selectively inhibit the proliferation of tumor cells [3].
Soft tissue metastasis of breast cancer whether to skeletal muscle or subcutaneous tissue, has been reported in some case series as well as in isolated case reports [1, 4]. The incidence of SMM originating from breast cancer was estimated from 3.3–11% in some case series [1, 2]. The most common sites of soft tissue metastasis of cancers include the abdominal wall, back, and thigh. Arm metastasis is very rare [2]. In our literature review, only eight cases of isolated arm metastasis from breast origin have been reported up to the present time [2, 5–9]. The rarity of these cases causes these asymptomatic metastatic patients to be missed by clinicians, especially after years of treating breast cancer.
On the other hand, in patients with breast cancer, a multidisciplinary approach ensures optimal care and enhances the safety and quality of life [10]. Physiotherapy can play a key role in the care of patients for mobility, symptoms control, and other problems; and it can support patients through all phases of treatment [10].
One of the common complications after breast surgery is lymphedema of the upper limb; the incidence is about 20% in breast cancer patients who underwent tumor resection and axillary lymph node dissection [11]. This complication may occur immediately or years after surgery and it causes limb and shoulder pain, and decrease the quality of life of patients due to decreased range of limb motion [11]. When this complication occurs, surgeons recommend patients to undergo a rehabilitation program such as physiotherapy.
We herein report an interesting case of a detected metastasis to the biceps muscle during the lymph therapy of a breast cancer patient by a physiotherapist, six years after mastectomy.
Case description
Previous history
A 25 year woman had been diagnosed with locally advanced left-sided breast cancer (T4N2M0) in August 2011 and had undergone a modified radical mastectomy after four cycles of neoadjuvant chemotherapy with doxorubicin and cyclophosphamide. The tumor had been down-staged from 10 cm to 3 cm and then resected via a mastectomy and axillary lymph node dissection. The histopathological examination had shown invasive ductal carcinoma with nuclear grade III, and nine involved lymph nodes out of thirteen dissected axillary nodes. Immunohistochemistry (IHC) and subsequent fluorescence in situ hybridization (FISH) evaluation had shown negative staining for estrogen receptor (ER), progesterone receptor (PR) and the human epidermal growth factor receptor 2 (HER2), Ki-67 was 5%. Her treatment had been completed by adjuvant sequential four cycles of docetaxel followed by external radiation therapy to the chest wall and regional lymph nodes.
Present complication
She had attended the breast clinic as a regular follow up for 6 years, and her last exam had been carried out in September 2017, including an extensive metastatic workup as a candidate for breast reconstruction scheduled for January 2018.
The patient was referred to the physiotherapy clinic for the treatment of lymphedema in December 2017 (six years after the initial diagnosis of the primary tumor). She had just begun a course of manual lymph therapy in order to improve her arm condition. During the lymph therapy a non-tender well-defined mass (2*3 cm) was detected in the medial aspect of the left arm for the first time by the physiotherapist (Fig. 1). The lymphotherapist interrupted the treatment and referred her to the breast surgery clinic. After a physical examination, the surgeon requested a magnetic resonance imaging (MRI).
Location of the left arm metastasis before (left) and after excision (right).
The MRI delineated a well-defined mass in the soft tissue of the upper arm (Fig. 2). Core needle biopsy of the mass revealed a metastatic adenocarcinoma with breast origin. IHC assay confirmed discordance in ER and PR between the primary breast cancer and soft tissue metastasis, as it rarely happens in metastatic lesions, demonstrating positive staining for ER and PR. The HER2 status (negative) and low Ki67 (8–10%) were the same as the primary tumor.
Magnetic resonance imaging (MRI) showing well-defined mass.
Positron emission tomography/computed tomography (PET/CT) with 18F-Fluorodeoxyglucose was carried in order to check for any other metastasis. It confirmed a solitary three centimeters nodule with a high FDG uptake (SUVmax ≥18) in the upper part of the left arm. No other positive or suspicious lesion was found throughout the scan.
The treatment plan was discussed in a multidisciplinary breast tumor board, including specialists in surgical, medial and radiation oncology, radiology, physiotherapy, and nuclear medicine. Local surgical treatment of the metastatic lesion followed by systemic therapy was selected as the best treatment option. Local excision of the mass in December 2017 confirmed an intermediate grade, ER positive, PR positive, and HER2 negative invasive ductal carcinoma of the breast. Systemic therapy was then instituted, including six courses of cyclophosphamide and docetaxel; tamoxifen was subsequently prescribed.
Patient status
The patient did well with no further metastasis of the cancer after more than two years of the last surgery. She has attended again for lymphedema management. She is doing well and in the final examination in March 2020, our patient had not any evidence of recurrent breast cancer or metastasis to other organs. She does not plan any more for breast reconstruction.
Discussion
Herein, we report a rare case of soft tissue metastasis to the arm following breast cancer; detected during physiotherapy for lymphedema 5 years after treatment. To the best of our knowledge, with the present reported case, only nine cases of arm metastasis originating from breast cancer have been reported globally (Table 1). However, it should be noted that in some case reports of soft tissue metastasis, the exact location of the metastasis or the primary site of the tumor has not been reported. Due to incomplete reports of some case series, the number of metastases of breast cancer to the arm may be higher. Table 1 shows the time interval between breast cancer diagnosis for the first time and appearance of arm metastases in the reported cases. In three case reports, a long time interval (25, 15, and 6 years) has been reported [8, 9]. Since, muscle metastasis often remains asymptomatic and has no physical signs; it could easily be missed, especially after many years from the cancer treatment. Awareness of this occurrence is extremely important for all disciplines that contribute in cancer care.
Case series and case report of breast cancer metastatic to soft tissue of arm
NA: Not applicable. *Total number is soft tissue metastasis reported with different origin. **Total number is muscle metastasis from breast cancer.
In the present case, arm metastasis was dicovered by the physiotherapist during lymph therapy. As a part of treatment in cancer patients, physiotherapy has an important role in postoperative physical rehabilitation, preventing and treating complications such as lymphedema [12]. Several studies reported physiotherapist contribution in cancer care with present physiotherapy modalities applied for lymphedema therapy [13]. In the present case report, we want to emphasize the role of the physiotherapists during care of patients with a previous history of cancer. We believe that sharing knowledge and education about the rare metastases would assist the physiotherapists in becoming more alert about the suspicious lesions, and report them to other members of the cancer treatment team.
Another point about the presentation of this report is that the related published case reports and case series implied a poor prognosis, and a limited perspective for treatment outcomes in patients with soft tissue metastasis. Therefore, the management of patients should be individualized depending on the site and behavior of the primary tumor.
Although arm metastasis in our patient was detected by MRI and it was confirmed by PET/CT scan, our review of the literature showed that PET/CT has a higher sensitivity than MRI for detecting unsuspected skeletal muscle metastases, and should be considered as a sensitive tool for this purpose. Because of limited specificity of imaging with MRI, it may not be able to differentiate between tumors and non-tumor lesions [14].
The prognosis and appropriate treatment of skeletal muscle metastasis are uncertain, however, surgical wide excision has been recommended especially for painful isolated masses [7]. Regarding the positive hormone receptors and negative HER2 status of the lesion and the long interval between primary tumor treatment and occurrence of isolated metastasis in the present case, wide local excision was done before systemic therapy and now she is taking tamoxifen.
In conclusion, solitary soft tissue metastases to the upper extremity from primary breast cancer, specifically after more than 5 years of curative treatment, are very rare. The small size of these lesions and the lack of specific clinical symptoms cause them to be undiagnosed for a prolonged period, as they are mostly detected incidentally [1]. PET/CT and MRI are preferable modalities for detection of soft tissue metastasis. Core needle biopsy is necessary to confirm the diagnosis and the site of origin. Systemic therapy subsequent to local surgery is an acceptable treatment with a good prognosis. It seems that physiotherapists, as an important member of the multidisciplinary team in the care and treatment of breast cancer patients, should be aware of this rare type of metastasis in soft tissues. Based on our knowledge, no article has reported a case of metastasis in cancer patients detected by a physiotherapist and the majority of literature addressed the role of the physiotherapist in palliative cares [11–13]. This case report for the first time has shown another important role of physiotherapists in cancerous patients.
Conflict of interest
The authors have none to declare.
Ethical consideration
The patient signed a written inform consent.