Surgical Management of Breast Cancer Developing Along the Pathway of a Ventriculoperitoneal Shunt: A Case Report.

BACKGROUND Ventriculoperitoneal shunts are commonly used in neurosurgery for the treatment of hydrocephalus. This case report details an unusual instance where breast cancer developed along the pathway of an existing ventriculoperitoneal shunt. CASE REPORT An 86-year-old woman, who previously underwent ventriculoperitoneal shunt placement for normal-pressure hydrocephalus, visited our hospital upon detecting a mass in her left breast. The physical examination discovered an irregular mass located at the 9 o'clock position of the left breast. Subsequent breast ultrasonography identified a 36 mm mass with indistinct borders, rough margins, and signs of skin infiltration. Invasive ductal carcinoma of a triple-negative subtype was diagnosed through a core-needle biopsy. Contrast-enhanced computed tomography indicated the ventriculoperitoneal shunt's pathway, running from the left ventricle, passing through the center of the breast mass, and leading into the abdominal cavity. Fears of shunt occlusion and potential infection due to the untreated breast cancer prompted surgical intervention after consultation with the neurosurgeon. The surgery involved rerouting the ventriculoperitoneal shunt from the left thoracoabdomen to the right, performing a left mastectomy, and removing the fistula in the abdominal wall to minimize the risk of cancer recurrence along the shunt pathway. Postoperative histopathological examination confirmed the initial diagnosis of invasive ductal carcinoma of a triple-negative subtype, with no malignancy detected in the removed abdominal wall fistula. CONCLUSIONS Taking into account prior cases of cancer metastasizing distantly due to ventriculoperitoneal shunts, our case emphasizes the necessity to consider additional preventative measures against cancer seeding. This approach is particularly significant when treating breast cancer that arises along the pathway of a ventriculoperitoneal shunt, apart from performing conventional breast cancer surgery.