Gallbladder Melanoma Presenting with Acute RUQ Pain

We present a case of a 37 year old male with multiple co-morbidities including hemophilia A, HIV, and chronic hepatitis C who presented with progressively worsening right upper quadrant pain and intermittent nausea. Ultrasound demonstrated polypoid echogenic lesions along the gallbladder wall with flow on power Doppler. CT scan of the abdomen was subsequently performed and demonstrated enhancement of the gallbladder lesions. An MRI of the abdomen was also obtained and showed a dominant T1 hyper intense enhancing mass involving the gallbladder lumen, multiple enlarged lymph nodes and enhancing hepatic lesions promoting peripheral capsular retraction. The patient subsequently underwent diagnostic cholecystectomy and liver biopsy. Surgical pathology of the gallbladder was diagnostic for malignant melanoma, with liver biopsies also diagnostic for metastatic malignant melanoma. Frederico F*, Weatherly B, Weiss E, Carroll B and Earl T Department of Radiology, The University of Mississippi Medical Center, USA Frederico F, et al. Clinics in Oncology Radiological Techniques and Scans Remedy Publications LLC., | http://clinicsinoncology.com/ 2016 | Volume 1 | Article 1039 2 Discussion Melanoma of the GI tract is relatively uncommon; antemortem diagnosis is made in only 1.5–4.4% of all patients with melanoma, however melanoma represents about one third of all metastatic disease of the GI tract and is found in 58% of postmortem specimens from patients with melanoma [3]. While melanoma has a clinical course that can involve diffuse metastases to many sites, [1,4] both primary and metastatic melanoma to the gallbladder are extremely rare, with only 20 cases of primary melanoma and 60 cases of metastatic melanoma to the gallbladder reported as of 2008. However, melanoma is the most common tumor to metastasize to the gallbladder, accounting for 30-60% of gallbladder metastases [1]. There have been several case reports of primary melanoma in the gallbladder [5-8] as well as metastatic melanoma in the gallbladder [1,2,9]. Gallbladder melanoma is most often found in patients with disseminated disease. It has been reported that 15% of patients who died of malignant melanoma had gallbladder metastasis at autopsy [1,2]. Clinically, however, gallbladder involvement by melanoma has been relatively occult, with symptoms seldom presenting [1], making our case of a patient who presented with symptoms suggestive of cholecystitis rare. Two case reports in the surgical and pathology literature have described gallbladder melanoma presenting with cholecystitis-like symptoms [5,8,9]. Our isolated presentation of gallbladder melanoma is, therefore, seldom seen among cases of this rare entity. During our patient’s diagnostic course, imaging of this rare case of gallbladder melanoma was obtained utilizing ultrasound, CT, and MRI. In particular, following concern raised for a neoplastic etiology due to the polypoid gallbladder lesions demonstrating both internal vascularity on US and enhancement on CT, the presence of T1 hyperintensity in both the gallbladder and metastatic liver lesions on MRI raised concern for melanoma as the likely etiology. This paramagnetic characteristic of melanin has been thought to be due to the presence of free radicals known to occur in melanin [10,11]. Others have theorized, however, that scavenging of paramagnetic metals by melanin accounts for their short T1 times [12]. The pathologic distinction between primary and secondary melanoma of the gallbladder is challenging. The primary site of disease may be elusive, as cutaneous melanomas may be small and regress over time, and thus may be difficult to detect. Due to the migration of melaninproducing cells from the neural crest to endodermal derivatives during embryogenesis, there are some melanocytes in gallbladder mucosa, making development of primary gallbladder melanoma a possibility [1]. In addition to a solitary nature, pathologic characteristics considered requisite to make a diagnosis of primary gallbladder melanoma include a papillary or polypoid configuration arising from Figure 1A: Ultrasound B mode in the right upper quadrant demonstrates a echogenic mass in the body and fundus of the gallbladder. Figure 1B: Power Doppler demonstrating flow/vascularity in the central portion of the mass. Figure 2A: CT scan of the abdomen obtained before the administration of IV contrast demonstrates a hiperdense area in the fundus of the gallbladder. Figure 2B: Axial CT scan of the abdomen after administration of intravenous contrast demonstrates that the mass has avid enhancement. Figure 3: Axial and coronal T1 Fat Sat pre contrast imaging of the upper abdomen demonstrates multiple hyperintense T1 lesions in the liver, hyperintense T1 adenopathy in the porta-caval region and hyperintese gallbladder mass (better seen on the coronal plane). Frederico F, et al. Clinics in Oncology Radiological Techniques and Scans Remedy Publications LLC., | http://clinicsinoncology.com/ 2016 | Volume 1 | Article 1039 3 the gallbladder mucosa and the presence of junctional activity [5]. The true existence of primary gallbladder melanoma, however, has been questioned [6]. A final consideration in our presented case is the development of melanoma in an HIV patient. A study in Lancet in 2007 demonstrated a similarincidence of melanoma in patients with HIV and in immunosupreessed transplant recipients [13], suggesting that immunosuppression, rather than HIV infection itself ,is associated with incidence of melanoma.