Case presentation
Patient presentation
A 70-year-old female with a prior history of benign hyperplastic polyps four years earlier presented for elective follow-up outpatient colonoscopy. The patient’s past medical history included type II diabetes mellitus, hyperlipidemia, coronary artery disease, hypertension, and congestive heart failure with pulmonary hypertension. Family history was positive for lung carcinoma in her mother. The patient’s laboratory blood work taken from around the time of the colonoscopy had shown normal fat values [cholesterol 178 mg/dl: (normal, 100-200 mg/dl), triglycerides 149 mg/dl; (normal, 25-150 mg/dl), HDL 33 mg/dl; (normal, 40-59 mg/dl), LDL 115 mg/dl; (normal 0-129 mg/dl)], a slight anemia demonstrated by a mildly lowered Hb/Hct and normal WBC with normal differential and normal platelet count, normal TSH, and normal liver enzymes. On the present elective follow-up colonoscopy, mild diverticulosis, internal and external haemorrhoids and multiple polyps were found. Colonic polyps were removed and revealed a tubular adenoma within the ascending colon and the hepatic flexure, and hyperplastic polyps within the transverse colon, sigmoid colon and rectum. A second distinct rectosigmoid polyp measuring 0.6 cm showed changes of polypoid xanthoma.
Histology
Histopathologic examination of hematoxylin-eosin stained sections from the rectosigmoid polyp revealed colonic mucosal biopsy fragments showing an intact superficial colonic mucosa with mild hyperplastic change and a lamina propria entirely replaced by compactly arranged large, round to oval foamy cells with distinct cell membranes (Fig. 1 A-C). Nuclei of these cells were small, bland and centrally located with cytoplasm that contained multiple small vacuoles (Fig. 2). Colonic crypts showed mild crypt displacement by the expanding aggregate of foamy cells. Immunohistochemical stain was positive for CD68, negative for CAM 5.2 and special stain for mucicarmine was negative (Fig 3 A-C). Special stains for acid fast bacilli and fungal organisms were negative. Lastly, a Gram stain and PAS and PAS-D were negative, excluding presence of possible Whipple’s disease or other bacterial organisms.
Discussion
Xanthomas present as small polypoid changes in the mucosa with presence of lipid-laden macrophages in the lamina propria. The large number of lipid-laden cells results in the grossly yellowish (xanthomatous) appearance of the lesion. Xanthomas are found in the body and fundus of the stomach in the vast majority of cases [1]. In the stomach, these lesions are commonly associated with chronic gastritis [2], are documented to occur status post gastrectomy [3] and are assumed to arise as a reaction to tissue damage [4]. Rare cases of xanthomas in the small intestine have been described. One reported case of xanthomatosis of the small bowel was associated with chronic intestinal ischemia. Another report from the small bowel entailed a case of a 9-year-old patient with history of chemotherapy for Burkitt’s lymphoma one month prior to a partial small bowel resection for intestinal obstruction; in the absence of neoplasia, the xanthomatous changes were etiologically felt to represent observed obstruction [5]. The etiology of colonic type xanthomas remains unknown. Similar to gastric xanthomas, mucosal damage and chronic injury are presumed to have a role in the pathogenesis of this entity [6]. As a response to mucosal damage, lipids derived from cell membranes may be captured by the interstitial histiocytes [4]. Our patient did not demonstrate any regenerative changes in the mucosa overlying the rectosigmoid xanthoma. Yet, the patient did have a history of diverticulosis as well as multiple polyps, including hyperplastic polyps, which have been considered to be an exaggerated regenerative response to mucosal damage. Associated hyperplastic changes within the rectum and a history of hemorrhoids may be linked to the possibility of prolapse; however, rectal prolapse is usually not associated with a xanthomatous reaction. There is no documented relationship between the degree of hyperlipidemia and the development of xanthomas in the GI tract [7]. Isomoto et al. reported no relationship between gastric xanthomas and diabetes mellitus, hypercholesterolemia or skin xanthomas [8]. Nakasano et al. found diabetes mellitus, constipation and hyperlipidemia in 2, 1 and 7 patients of a total of 25 patients with colorectal xanthomas [9]. In 4 cases of rectosigmoid (colonic) xanthomas from Miliauskas, no association with cutaneous xanthomas or increased lipid levels were noted and only 1 patient had diabetes mellitus [10]. In our patient, there was a history of type II diabetes mellitus and hyperlipidemia which was controlled by medications as demonstrated by a normal laboratory lipid profile. Our case adds to the literature of this uncommonly described benign entity in the lower gastrointestinal tract. Uniquely, in this patient, the rectosigmoid (colonic) xanthoma presented with concurrent multiple benign polyps.
Acknowledgements
There exist no conflicts of interest, either personal or financial, which the authors need to disclose. No affiliations (e.g. employment, stock ownership, consultations, honoraria, expert testimony) exist with any organizations or entities having a direct personal or financial interest in the subject matter or materials discussed in this article.
References
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Address for correspondence
Anna M. Moran MD
Assistant Professor
Department of Pathology and Laboratory Medicine
University of Pennsylvania Health System
Penn Presbyterian Medical Center
51 North 39th Street
Suite W-542
Philadelphia, PA 19104
phone: 0-01-215-662-8548
fax: 0-01-215-662-1694
e-mail: anna.moran@uphs.upenn.edu
