P0211 - A Rare Presentation of Neuroendocrine Tumor in the Sigmoid Colon

Luis A. Gil, DO¹, Mihir Brahmbhatt, MD², Humberto J. Rios, MD³, Sarah Arvaneh, DO¹, Karthik Mohan, DO^4
1Larkin Community Hospital, Hialeah, FL; ²Larkin Community Hospital, Miami, FL; ³Larkin Community Hospital Palm Springs, Hialeah, FL; ⁴Larkin Community Hospital, South Miami, FL

Introduction: Neuroendocrine tumors (NET) of the colon are rare accounting for 0.6% of colorectal cancer, of which large cell NET are even fewer, comprising 0.2%. Large cell NET is known for its aggressive nature as metastatic disease is present at time of diagnosis.¹ To our knowledge, this would be the first reported case of asymptomatic large cell NET.

Case Description/Methods: An 86-year-old female with a past medical history of hypertension and hyperlipidemia was admitted to the hospital for a urinary tract infection. Laboratory studies were notable for hgb 11g/dL and found to be fecal occult blood positive. Patient on exam was noted to have a soft, non-distended, non-tender abdomen. CT abdomen and pelvis revealed bowel wall thickening of rectosigmoid colon with prominent subcentimeter superior rectal lymph nodes. Sigmoidoscopy revealed a 5 cm sigmoid mass from which biopsy was obtained. Biopsy indicated large cell NET with Ki-67 highly positive. Surgical team performed a rectosigmoid colectomy. Furthermore, 17 lymph nodes excised showed no sign of metastatic carcinoma. Hematology Oncology recommended oral chemotherapy; however, ultimately conservative management was chosen due to her age and comorbidities.

Discussion: While large cell NET is an extremely rare cause of colon cancer, it is aggressive with overall median survival 10.5 months and one year survival of 10%.¹,² In addition, highly positive Ki-67 ( >10%) is associated with extensive angioinvasion and metastatic disease potential.³ This case is unique due to an asymptomatic patient incidentally found to have a large cell NET, with no signs of metastases after biopsy despite Ki-67 highly positive. This case report shows an early presentation of an aggressive and rare colon malignancy that has otherwise not been documented.



References:



1. Bernick PE, Klimstra DS, Shia J, et al. Neuroendocrine Carcinomas of the Colon and Rectum. Dis Colon Rectum. 2004;47(2):163-169. doi:10.1007/s10350-003-0038-1

2. Gravante G, Markiewicz D, Madeddu F, Giordano P. CONTINUING MEDICAL EDUCATION FORMATION MÉDICALE CONTINUE Colonic Large-Cell Neuroendocrine Tumours. Vol 52.; 2009.



3. Minocha V, Shuja S, Ali R, Eid E. Large Cell Neuroendocrine Carcinoma of the Rectum Presenting with Extensive Metastatic Disease. Case Rep Oncol Med. 2014;2014:1-5. doi:10.1155/2014/386379


Figure: Imaging and pathology results. a: CT abdomen and pelvis with asterisk indicating bowel wall thickening; b: Sigmoid mass biopsy pathology slide showing large atypical cells with prominent nucleoli and abundant mitoses (40x); c: CT abdomen and pelvis indicating bowel wall thickening; d: Sigmoid mass biopsy pathology showing the tumor cells diffusely positive for INSM1 (marker of neuroendocrine differentiation).


Disclosures:
Luis Gil indicated no relevant financial relationships.
Mihir Brahmbhatt indicated no relevant financial relationships.
Humberto Rios indicated no relevant financial relationships.
Sarah Arvaneh indicated no relevant financial relationships.
Karthik Mohan indicated no relevant financial relationships.


Luis A. Gil, DO¹, Mihir Brahmbhatt, MD², Humberto J. Rios, MD³, Sarah Arvaneh, DO¹, Karthik Mohan, DO⁴. P0211 - A Rare Presentation of Neuroendocrine Tumor in the Sigmoid Colon, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.