Conclusions This is the first reported case of TLS in a patient with cholangiocarcinoma. TLS in patients with solid malignancies may be more common than expected. Acknowledgements Disclosure: The authors declare no conflict of interest.
A 41-year-old Caucasian female with a history of rectal pain and hemorrhoids was referred to our hospital by her primary care physician for further evaluation.

She first developed Inhibitors,research,lifescience,medical anal discomfort in 2011. She reported some discharge and weeping from the anorectal region. This was initially attributed to hemorrhoids. Her primary care physician noted a longstanding history of prolapsing internal and external hemorrhoids which were very symptomatic. She was seen by the colorectal surgeon at our hospital where an excisional hemorrhoidectomy was scheduled. In the operating room, an anorectal exam was performed under general anesthesia. Inspection of the anorectal region showed a large right anterior prolapsing Inhibitors,research,lifescience,medical hemorrhoid strangulated in appearance. This led to an internal component with an adjacent smaller internal and external hemorrhoid. The hemorrhoidectomy was then performed with sphincter muscle preservation. Pathologic examination revealed Inhibitors,research,lifescience,medical an aggregate of hemorrhoids along with a pedunculated acutely eroded malignant melanoma with foci of junctional component highly suggestive

of primary mucosal melanoma (Figure 1). The tumor measured 1.2 cm in thickness with an apparent 2 mm negative margin at the base. Figure 1 Surgical pathology from the initial hemorrhoidectomy revealed anal mucosal melanoma with melanoma pigment visible at (A) low power Inhibitors,research,lifescience,medical and (B) high power. Given this incidental diagnosis of mucosal melanoma a PET-CT of the whole body was performed as part of her metastatic workup. This showed a 1.4 cm × 1.3 cm enlarged right inguinal lymph node with increased FDG activity (SUV 4.0) which was highly suspicious for disease involvement. A core needle biopsy of this inguinal node done shortly thereafter confirmed

metastatic melanoma. The patient was then referred to medical oncology who recommended tumor Inhibitors,research,lifescience,medical cytogenetic analysis. A right superficial groin lymph node dissection was also recommended and performed revealing one out of seven dissected lymph nodes positive for metastatic melanoma. B-Raf genotype testing was found to be negative. The use of systemic therapy, such as immunotherapy, was discussed with the patient but she was hesitant to undergo this treatment considering some of the possible also side effects. The patient continued to undergo routine surveillance postoperatively. A physical exam and PET-CT was performed every few months. Approximately seven months after her superficial groin lymph node dissection a routine surveillance PET-CT demonstrated a prominent right groin lymph node measuring 4.2 cm × 3.1 cm significantly larger compared to previous examination and now highly Fasudil FDG-avid (SUV 19.5) (Figure 2). There was also a new soft tissue mass measuring 3.2 cm × 2.