Category: Monday Poster Session

P928 - Primary Advanced Gallbladder Malignant Melanoma Successfully Eradicated With Immunotherapy and BRAF Inhibitors

Monday, Oct 16
10:30 AM – 4:00 PM

Award: 2017 Presidential Poster Award

Category: Biliary/Pancreas       Sub-Category: Clinical Vignettes/Case Reports

Seifeldin Hakim, MD1, Molly Orosey, DO, MS2, Mitual Amin, MD1, Mitchell S. Cappell, MD, PhD, FACG1
1Oakland University William Beaumont School of Medicine, Royal Oak, MI; 2Beaumont Health, Royal Oak, MI
A 58-year-old male with past medical history significant for H. pylori positive gastric ulcer presented with pre-syncope. Physical examination revealed a vitally stable patient, with no jaundice or RUQ tenderness. CT pulmonary embolism protocol showed incidental biliary dilation and gallstones. Right upper quadrant US showed cholelithiasis and dilated CBD of 10 mm. Laboratory analysis revealed WBC=4.9bil/L, Hgb =13.5gm/dl, platelets=150k, ALP=322U/L, AST=178U/L, ALT=243U/L, TB=3.7U/L with direct portion=2.5U/L. ERCP was unsuccessful due to failure to canulate CBD. Laparoscopic cholecystectomy and open laparotomy were unsuccessful due to difficult resection. During laparotomy, firm fixed mass was found in gallbladder infundibulum and some fixed lymph nodes in the portal triad and hepatoduodenal ligament. Incisional biopsy with removal of stones and cholecystostomy were performed. MRCP showed intraluminal gallbladder heterogenous mass measuring 6 cm and multiple enlarged lymph nodes compressing the CBD. Microscopic pathology was consistent with malignant melanoma (image 1). Immunohistochemical stains were positive for S100, HMB-45 and SOX-10 (Image 2). CT chest, abdomen and pelvis, brain MRI and PET scan did not show evidence of other site involvement or metastasis. Ophthalmological examination was normal with no evidence of ocular melanoma. Dermatological evaluation was normal and random biopsies of skin nevi were negative for malignancy. He received nivolumab infusion then he was switched to debrafenib and trametinib. Most recent PET scan, body CT and MRCP showed good response to immunotherapy with no evidence of metastasis or active disease at 14 months follow-up visit. Later on, he underwent successful cholecystectomy, central hepatectomy, and portal lymphadenectomy. Microscopic pathology showed no evidence of melanoma and failure to stain with S-100 or SOX-10 in the entire resected specimen (image 3). The patient is stable at 8 weeks post-operative follow-up visit with no evidence of melanoma recurrence.

Primary gall bladder melanoma is a very rare type of melanoma. Some authors doubt its existence and believe it is secondary to occult primary melanoma elsewhere. Gall bladder is a relatively common site for melanoma metastasis. Treatment of melanoma is usually surgical. We believe this is the first case of advanced primary melanoma of the gallbladder, which was successfully treated and eradicated by immunotherapy and BRAF inhibitors.

Supported by Industry Grant: No

Gallbladder biopsy showing multiple nucleated cells with thickening of the mucosa and submucosa.
Microscopic pathology shows positive staining with immunohistochemistry S100 and SOX-10 stain. (Before treatment)
Left inset shows that the gallbladder wall is replaced completely with fibrous tissue with no evidence of cells or tumor. Right inset show failure to stain with immunohistochemistry S100 completely. (After treatment)

Citation: . PRIMARY ADVANCED GALLBLADDER MALIGNANT MELANOMA SUCCESSFULLY ERADICATED WITH IMMUNOTHERAPY AND BRAF INHIBITORS. Program No. P928. World Congress of Gastroenterology at ACG2017 Meeting Abstracts. Orlando, FL: American College of Gastroenterology.

Seifeldin Hakim

Oakland University William Beaumont School of Medicine
Royal Oak, Michigan