eP365 - Pruritic Pustular Rash as a Unique Paraneoplastic Feature of Rectal Cancer – a Case Report

Purpose/Background: Paraneoplastic syndromes are a subset of intricate clinical manifestations of occult malignancy causing an altered immune system. These symptoms do not stem directly from tumor invasion or metastasis but typically arise due to malignancy producing various hormones, peptides, cytokines, or lipids. The most affected organs are the skin, brain, spinal cord, and hematological systems. Paraneoplastic Syndromes can be the first sign of malignancy and occur in up to 8% of cancer patients. Neurological manifestations in the form of neuropathies are the most common presentation. It was first suggested by Hebra in 1868 that skin pigmentation could indicate the presence of visceral cancer. We present a case of pruritic pustular rash on hands, which was the initial presenting symptom of rectal cancer.Methods/Interventions: A 51-year-old female with no significant past medical history or surgical history was diagnosed with rectal cancer. Her family history was important for polyps in her father and colon cancer in her paternal aunt at 60 years of age. Screening Colonoscopy at 50 showed a benign hyperplastic polyp in the descending colon. Subsequently, she developed a pruritic pustular rash on her hands with minimal improvement after one year of treatment. She experienced deep perineal excoriation and was seen in the office. She had a flexible sigmoidoscopy which was significant for mucosal lesions in the rectum concerning cancer. Completion colonoscopy showed a 1-1.5 cm discoid lesion in the rectum, about 10-15 cm from the anal verge. Biopsy was significant for well-differentiated adenocarcinoma. Computed tomography of the chest, abdomen, and pelvis was consistent with mesenteric haziness concerning mesenteric adenitis. Magnetic Resonance Imaging of the pelvis showed a left mid-rectal mass compatible with T2 rectal cancer and small peri-rectal lymph nodes. The patient was discussed in a multi-disciplinary tumor board and recommended to have surgery followed by adjuvant chemotherapy + chemoradiation.Results/Outcomes: She underwent Laparoscopic low anterior resection with diverting loop ileostomy. Pathology was consistent with well-differentiated, low-grade invasive adenocarcinoma invading the submucosa (T1), 2/13 peri-colonic positive lymph nodes (N1), and negative margins. Genetic testing for MLH1, MSH2, MSH6, EPCAM, PMS2 and MYH was negative. She received 8 cycles of FOLFOX therapy with radiation and Capecitabine. Her ileostomy was reversed within 6 months of the index procedure. She experienced instant resolution of her rash following the index procedure. Surveillance colonoscopies have shown patent coloanal anastomosis with no concerning features.Conclusion/

Discussion: Paraneoplastic syndrome is a diagnosis of exclusion. It can be the first sign of malignancy and occurs in up to 8% of cancer patients. A comprehensive and thorough workup is indispensable to eliminate other potential sources of symptoms. If standard treatments fail to alleviate the symptoms, occult malignancy should be considered as a potential underlying cause.