Solitary pancreatic metastasis from breast cancer: case report and review of literature

ABSTRACT CONTEXT: Pancreatic metastases from primary malignant tumors at other sites are rare, constituting about 2% of the neoplasms that affect the pancreas. Pancreatic metastasis from breast cancer is extremely rare and difficult to diagnose, because its clinical and radiological presentation is similar to that of a primary pancreatic tumor. CASE REPORT: A 64-year-old female developed a lesion in the pancreatic tail 24 months after neoadjuvant therapy, surgery and adjuvant radiation therapy for right-side breast cancer (ductal carcinoma). She underwent distal pancreatectomy with splenectomy and left adrenalectomy, and presented an uneventful outcome. The immunohistochemical analysis on the surgical specimen suggested that the lesion originated from the breast. CONCLUSION: In cases of pancreatic lesions detected in patients with a previous history of breast neoplasm, the possibility of pancreatic metastasis should be carefully considered.


INTRODUCTION
Pancreatic metastases from primary malignant tumors at other sites are rare, constituting about 2% of the neoplasms that affect the pancreas. 1 In most cases, the involvement occurs through hematological and lymphatic dissemination, as in cases of kidney and lung carcinomas.
It can also occur through contiguous invasion of neighboring organs such as the liver, stomach and spleen. Pancreatic metastasis from breast cancer is extremely rare and difficult to diagnose, because its clinical and radiological presentation is similar to that of a primary pancreatic tumor. [2][3][4][5] The objective of the present study was to report on a case of pancreatic metastasis of breast cancer, along with the treatment that was proposed.

CASE REPORT
A 64-year-old female underwent neoadjuvant chemotherapy consisting of doxorubicin, cyclophosphamide and paclitaxel, with subsequent quadrantectomy and axillary lymph node dissection due to a right-side breast neoplasm. Histopathological examination revealed a ductal carcinoma classified as T2N2M0, consisting of a 4-cm tumor with spreading to six axillary lymph nodes but without distant spreading to bones, liver, brain or lungs). It was triple-negative, for estrogen, progesterone and human epidermal growth factor receptor 2 (HER2) receptors.
Radiation therapy was subsequently implemented. The patient was then followed up with serial investigations (mammogram, bone scintigraphy scan and computed tomography scans of the cranium, thorax and abdomen) for locoregional and distant relapses every six months.
Twenty-four months after receiving the diagnosis, she evolved with a complaint of left-flank pain, inappetence and loss of seven kilograms in four months. She presented dyspeptic symptoms characterized by early satiety and pain in the upper abdomen after feeding. On physical examination, the abdomen was painful to deep palpation. There was no evidence of relevant laboratory abnormalities.
Abdominal computed tomography demonstrated a hypervascularized solid lesion of 6.6 cm x 6.0 cm x 7.0 cm in the tail of the pancreas. It had an irregular outline and partially defined borders, pre- On the other hand, negativity for the MUC-5AC, CEA and CA-19.9 markers does not favor a pancreatobiliary origin and favors the breast as the primary site. A chemotherapy regimen consisting of paclitaxel was administered for 12 weeks following the patient's recovery from the operation, and currently she is being followed up with serial screenings for locoregional and distant spreading of disease every six months. As of 18 months after the diagnosis was made, there is no evidence of active disease.

DISCUSSION
Breast cancer causes metastases especially to bones, liver and lungs. Pancreatic involvement in solitary metastases from a primary breast neoplasm is rare, occurring in less than 3% of the cases. A review of the literature was conducted through an online search for the Medical Subject Headings (MeSH) terms "breast neoplasms", "pancreas" and "neoplasm metastasis" in MEDLINE (via PubMed) and LILACS (via BVS) ( Table 1). We included original studies that reported single cases or case series of this disease or correlated conditions. All the papers were checked according         The most accurate diagnostic method is pancreatic biopsy. Some studies have suggested that fine-needle biopsies guided by endoscopic ultrasound or percutaneously should be used. 3 The unavailability both of tests for this marker and of endoscopic ultrasound at our service precluded their use in the present case; however, this should not prevent the oncology and surgery teams from recommending operative treatment in cases without widespread disease.
The prognosis for patients with pancreatic metastatic disease is usually better than for patients with primary pancreatic tumors. 2 Masetti et al. analyzed the prognostic factors relating to metastatic tumors in the pancreas and found two and five-year survival rates of 57.1% and 34.3% in cases of pancreatic metastasis due to breast cancer, respectively. 28 Surgical resection in cases with disease limited to the pancreas is considered to be the main form of treatment, despite its morbidity. 3

CONCLUSION
Based on this study and the evidence available to date, it may be concluded that in cases of pancreatic lesions detected in patients with previous histories of breast neoplasms, the possibility of pancreatic metastasis should be carefully considered.
common than to the tail, and the most common histological type was lobular carcinoma; the predominant metastatic pattern was solitary. The average interval between the diagnoses of primary breast neoplasm and pancreatic metastasis was 43.3 months. 2 In our case, the patient presented metastasis to the region of the tail of the pancreas, with a histopathological diagnosis of ductal carcinoma, and the asymptomatic interval was 24 months.
The clinical signs of this condition are unspecific, with abdominal pain and obstructive jaundice as the main findings. 4 The absence