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Journal of Clinical Oncology, Vol 25, No 25 (September 1), 2007: pp. 4012-4014 © 2007 American Society of Clinical Oncology. DOI: 10.1200/JCO.2007.12.4214
Retrorectal Cystic Hamartoma As Benign Cause of CA 19-9 ElevationDepartment of Medical Oncology, Fundación Hospital Alcorcón, Alcorcón, Spain
Human Genetics Group, Spanish National Cancer Research Centre, Madrid, Spain
Department of Pathology, Fundación Hospital Alcorcón, Alcorcón, Spain
Comparative Pathology Unit, Spanish National Cancer Research Centre, Madrid, Spain
Department of Radiodiagnostics, Fundación Hospital Alcorcón, Alcorcón, Spain
Department of Surgery, Fundación Hospital Alcorcón, Alcorcón, Spain A 38-year-old woman, who was a member of a family with hereditary nonpolyposis colorectal cancer (HNPCC) syndrome, first submitted for genetic counseling in November 2005. Mismatch repair–gene analysis showed a GT deletion at codon 1717_1718 in exon 15 of MLH1. Medical surveillance was recommended and screening for colonic and extracolonic malignancies was performed. Screening included transvaginal ultrasound, urine cytology, upper endoscopy, colonoscopy, computed tomography scan, and laboratory studies with CBC, chemistry, and serum tumor markers (CA 125, CA 15-3, CA 19-9, carcinoembryonic antigen, alpha-fetoprotein, human gonadotropin). Colonoscopy showed compression of the posterior rectum without mucosa changes. CA 19-9 was 61 U/mL (normal value, 0 to 40 U/mL) confirmed in two consecutive determinations. Computed tomography scans before and after contrast injection demonstrated a well-circumscribed cystic mass of 10 x 7.5 x 8.5 cm lying in the retro- and laterorectal space with enhancing regular wall and septa. On the liver, multiple cystic lesions were also described. Magnetic resonance imaging confirmed these findings (Fig 1; yellow arrows). All other examinations were into normal parameters. A radiological guided fine needle aspiration was performed obtaining only necrotic tissue. Finally the patient underwent a complete simple excision of the mass through a sacral approach. The pathological examination revealed a 5-cm multicystic lesion with discontinuous bundles of smooth muscle fibers and stratified squamous, transitional, and ciliated columnar epithelium considered as a retrorectal cystic hamartoma (Fig 2A and 2B). Cytoplasmatic staining for CA 19-9 was observed in mucinous secretory epithelium, especially in goblet cells (Fig 3A and 3B; blue arrows). The microsatellite instability analysis, using the BAT 26 marker, was negative.
After surgery a positron emission tomography scan was performed showing no pathological intakes. Ca 19-9 decreased into normal range 1 month after resection. HNPCC, also referred to as the Lynch syndrome, is the most common form of hereditary colon cancer.1 It exhibits an autosomal dominant inheritance pattern, and affected individuals carry an 80% lifetime risk of colorectal cancer. Type I HNPCC is defined by the occurrence of only colorectal cancer, while families with type II HNPCC, Turcot syndrome and Muir-Torre syndrome also display extracolonic tumors (uterus, stomach, ovary, renal, pelvis and urinary tract, biliary tract, small intestine, brain, and skin).2,3 HNPCC tumors present DNA microsatellite instability due to dysfunction of mismatch-repair genes. More than 90% of HNPCC cases are accounted for by germline mutations in hMSH2 or hMLH1 genes.4 Retrorectal cystic hamartomas, also known as tailguts cysts, are rare congenital lesions thought to arise from the remnants of the embryonic postnatal gut.5 They predominantly occur as retrorectal multicystic masses in middle-aged women. Nearly one half of patients remain asymptomatic at the time of diagnosis. Histologically, these kind of cysts can contain a variety of epithelia, that include stratified squamous, transitional, or ciliated columnar, and cuboidal mucus secreting.6 Seventeen cases of malignancy arising from this kind of hamartoma have been reported. Complete excision is the treatment of choice even in benign lesions. In our patient, affected with a hereditary cancer syndrome, the presence of a pelvic mass and a rising CA 19-9 was initially judged as probably malignant. Pathological studies rejected this suspicion, showing the mucinous epithelium of the hamartoma as the cause of the tumor marker elevation. In addition, no genetic instability was found, so a relation with the HNPCC and MLH1 mutation seems unlikely. Retrorectal hamartomas are infrequent lesions that not only can elevate tumor markers but also can be mistaken for ovarian7 or rectal tumors.8 It is important to keep this possibility in mind before assuming the findings as malignant, especially in patients with hereditary syndromes who can suffer from increased anxiety. Despite being benign lesions, retrorectal cystic hamartomas should be routinely resected in order to confirm diagnosis and avoid malignant transformation or local complications. AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST The author(s) indicated no potential conflicts of interest.
REFERENCES 1. Jo W-S, Chung DC: Genetics of hereditary colorectal cancer. Semin Oncol 32:11-23, 2005[Medline] 2. Watson P, Lynch HT: The tumor spectrum in HNPCC. Anticancer Res 14:1635-1639, 1994[Medline] 3. Hamilton SR, Liu B, Parsons RE, et al: The molecular basis of Turcot's syndrome. N Engl J Med 332:839-847, 1995 4. Lynch HT, de la Chapelle A: Genetic susceptibility to non-polyposis colorectal cancer. J Med Genet 36:801-818, 1999 5. Killingsworth C, Gadacz TR: Tailgut cyst (retrorectal cystic hamartoma): Report of a case and review of the literature. Am Surg 71:666-673, 2005[Medline] 6. Hjermstad BM, Helwig EB: Tailgut cysts: Report of 53 cases. Am J Clin Pathol 89:139-147, 1988[Medline] 7. Tampi C, Lotwala V, Lakdawala M, et al: Retrorectal cyst hamartoma (tailgut cyst) with malignant transformation. Gynecol Oncol 105:266-268, 2007[CrossRef][Medline] 8. Graadt van Roggen JF, Welvaart K, de Roos A, et al: Adenocarcinoma arising within a tailgut cyst: Clinicopathological description and follow up of an unusual case. J Clin Pathol 52:310-312, 1999[Abstract]
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Copyright © 2007 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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