Primary Clear Cell Adenocarcinoma of the Colon: A Case Report and Review
Camille Thelin, MS, MD; Caroline R. Alquist, MD, PhD; Lee S. Engel, MD, PhD; Tracy Dewenter, MD
A case of primary clear cell adenocarcinoma of the colon, a rare oncologic variant, was diagnosed in a 25-year- oldman who presented with partial bowel obstruction. To understand better the pathology of this neoplasm, a retrospective review of Entrez PubMed entries describing primary clear cell adenocarcinoma of the colon and/or rectum was performed. Only 13 previous cases of primary clear cell adenocarcinoma of the colon and/or rectum have been reported, with an average presentation age of 57 years and generally afflicting the descending colon of men. Herein we present a case occurring in the distal ascending colon of the youngest patient in the literature to date. Our patient’s diagnosis is rare in occurrence, location, and age of onset.
INTRODUCTION Primary clear cell adenocarcinoma of the colon is an uncommon oncologic diagnosis. A reviewof Entrez PubMed publications revealed 13 previously reported cases. 1-13 Herein, we describe the 14th and youngest patient with this diagnosis reported in the literature to date: a 25-year-old man with stage IV primary clear cell adenocarcinoma of the distal ascending colon. CASE REPORT A 25-year-old man presented to the emergency depart- ment with abdominal discomfort and distention, nausea, and several episodes of bilious vomiting for two weeks. Bilious emesis and abdominal pain was not associated with any specific foods, medicines, or positions. His last bowel movement had occurredmore than one week prior andwas described as “foamy,” but flatus had continued. The review of systems was negative for diarrhea, melena, hematochezia, hematemesis, or history of hemorrhoids. He also denied any fevers, chills, prior hospitalizations, sick contacts, or recent travel history. Prior to coming to our institution, he had visited two different emergency rooms with the same complaints and was discharged fromeachwith a diagnosis of gastroenteritis. A computed tomography (CT) scan of the abdomen and pelvis was performed during one of these visits. The scan was unavailable to our institution; however, he reported be- ing told that there was nonspecific thickening of the bowel wall for which he should schedule a follow-up appointment with a general surgeon. His past medical history was significant only for child- hood asthma. He had no past surgical history or allergies.
He reported only occasional, but not recent, non-steroidal, anti-inflammatory drug use for pain. He denied any tobacco or illicit drug use, but a social history review was positive for the occasional alcoholic beverage. His family historywas relevant for one grandfather with colon cancer of unknown type or age of onset. Physical exam revealed unremarkable vital signs, aside from a slight tachycardia and the appearance of mild dis- comfort. Abdominal distention and decreased bowel sounds in all four abdominal quadrants, without tinkles or rushes, were noted. Mid-epigastric and right-upper quadrant (RUQ) tenderness to palpation, without guarding or rebound, also was noted. A complete blood count and comprehensive metabolic profile were normal except for mild hyponatremia (133 mEq/L). A carcinoembryonic antigen (CEA) level was el- evated (12.3 ng/mL). A CT scan of the abdomen and pelvis found a mass-like thickening at the hepatic flexure, as well as dilated small bowel (>4 cm) and large bowel proximal to the mass (Figure 1A). Scattered lymph nodes were seen throughout the abdomen, but weremost prominent adjacent to the area of thickening (Figure 1B). No other evidence of malignancy was evident on the CT scan. He underwent an exploratory laparotomy with right hemicolectomy and was found to have a partial large bowel obstruction secondary to a stenotic tumor mass at the distal ascending colon/hepatic flexure. An ileocolonic anastamosis was performed at this time. Surgical pathology evaluation of the right hemicolecto- my specimen revealed a circumferential mass (3 cm) within the distal ascending colon which involved the full thickness of the colonic wall. The tumor extended into the pericolonic fat to abut the serosa. Dilation of the colon proximal to the mass was noted, with flattening of the mucosal folds. Histo-
J La State Med Soc VOL 166 July/August 2014 143
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