The use of robotic bronchoscopy with EBUS and pulsed electric field ablation for metastatic melanoma in a lung nodule

Abstract

Malignant melanoma is one of the lethal forms of cancer, with approximately 8,290 deaths
expected in 2024.1 Information available on melanomas of unknown primary origin remains
limited. A review by Song theorized that the most likely hypothesis of its etiology is immune
mediated regression of the primary after metastasis has occurred.3 Our case represents a patient
with metastatic melanoma found in both pancreatic and lung tissues. The pancreatic biopsy
results were consistent with malignant melanoma. Pancreatic melanoma is more commonly
a site of metastasis than a primary tumor, and in this case, the presentation was nonspecific.
Regardless, malignant melanoma is treated by immunomodulator therapy involving PD1
inhibitors alone or in combination with ipilimumab. That being said, the patient was considered
for a biopsy of the lung nodule with Pulsed Electric Field ablation as a concomitant treatment
approach by the oncology team.
After undergoing the biopsy but before starting treatment, the Pulse Electrical Field was used
for its properties of targeting the tumor site with its abscopal effect, leading to a process called
pyroptosis. Pyroptosis leads to inflammatory vesicles filled with damage-associated molecular
patterns (DAMPs), which are later released from the cell via gadermin D, GSDMD pores to elicit
an immune response.8 Treatment was successful at 8-month follow-up CT scan, which showed
no recurrence of the lesions. In summary, PEF leads to tumor shrinkage both within the targeted
treatment area and at distant sites outside the treatment field. This case is the first to use pulse
electrical field ablation as an adjunct to immunotherapy for malignant lesions.

Keywords: Endobronchial, melanoma, Pulse electrical field ablation, lung nodule, abscopal