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 Table of Contents  
Year : 2016  |  Volume : 6  |  Issue : 1  |  Page : 47-50

Adenocarcinoma arising in a chronic fistula-in-ano and presenting as a gluteal mass

1 Department of Surgery, Federal Medical Centre, Nguru, Yobe State, Nigeria
2 Department of Pathology, University of Maiduguri Teaching Hospital, Maiduguri, Nigeria

Date of Web Publication28-Jul-2016

Correspondence Address:
Dr. Ibrahim E Suleiman
Department of Surgery, Federal Medical Centre, Nguru, Yobe State
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2278-9596.187197

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The occurrence of adenocarcinoma within a fistula-in-ano is a rare phenomenon, more so when it arises within the fistula. A 54-year-old man presented with a slow-growing, painless, left gluteal mass of 5 years' duration. There was history suggestive of chronic fistula-in-ano, for which he never had orthodox treatment. On examination, he looked well-preserved. The left gluteal mass measured about 20 × 18 × 10 cm with multiple sinuses discharging mucus and pus. There were tracts connecting the mass with sinuses in the anus. The gluteal mass was excised; histology revealed well-differentiated adenocarcinoma, probably from the rectum. He had abdominoperineal excision of the rectum 3 months later, and a fasciocutaneous flap was raised from the right thigh to cover the gluteal defect. Histological examination did not reveal any malignant lesion in the excised rectum. Malignant transformation does occur within a chronic fistula-in-ano. A high index of suspicion is essential to diagnose such cases; histological examination is therefore, very essential for all tissues resected at surgery for fistula-in-ano. Prompt and adequate treatment will save the patient from a protracted and debilitating course of the disease.

Keywords: Adenocarcinoma, chronic fistula-in-ano, gluteal mass, multiple perineal sinues

How to cite this article:
Suleiman IE, Pindiga UH, Waziri AM, Abubakar BM. Adenocarcinoma arising in a chronic fistula-in-ano and presenting as a gluteal mass. Arch Int Surg 2016;6:47-50

How to cite this URL:
Suleiman IE, Pindiga UH, Waziri AM, Abubakar BM. Adenocarcinoma arising in a chronic fistula-in-ano and presenting as a gluteal mass. Arch Int Surg [serial online] 2016 [cited 2021 Oct 17];6:47-50. Available from:

  Introduction Top

The occurrence of adenocarcinoma within a fistula-in-ano is a rare phenomenon. When it does occur, it is most often due to seeding of tumor cells from a carcinoma in the rectum or a low rectal or anal cancer presenting as an anal fistula but adenocarcinoma arising within a chronic fistula-in-ano is indeed very rare with less than 150 cases of mucinous adenocarcinoma (the most common histological subtype) reported in the literature.[1] A 54-year-old man presented to hospital for the first time with a left gluteal mass with multiple discharging sinuses. This was histologically diagnosed as adenocarcinoma arising from a chronic fistula-in-ano. We present the management of his case and a review of the literature.

  Case Report Top

A 54-year-old man presented with a slow-growing, left gluteal mass of 5 years' duration. The mass discharged mucoid material and pus from multiple openings and it was painless. He had a 45-year history of recurrent multiple discharging sinuses around his anus, suggestive of chronic fistula-in-ano for which he never had orthodox treatment. There was no history of chronic diarrhoea, chronic cough, or weight loss. He was not known to have diabetes mellitus or retroviral disease. On examination, he looked fairly preserved. The left gluteal mass was overlying the ischial tuberosity and measured about 20 × 18 × 10 cm with multiple sinuses discharging mucus and pus while the surrounding skin was hyperpigmented and indurated [Figure 1].
Figure 1: Multiple sinuses discharging mucus and pus; the surrounding skin is hyperpigmented and indurated

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Two external fistulae openings were seen at the perianal region; one located at the 5 o'clock position, 3 cm from the anal verge and the other at the 7 o'clock position, 4 cm from the anal verge. An internal opening was felt at the 3 o'clock position, 2 cm into the anus. The inguinal lymph nodes were not palpably enlarged. There was no palpable mass on digital examination of the rectum. An assessment of an inflammatory mass resulting from a chronic fistula-in-ano was made. He was negative on retroviral screening, random blood sugar done was 5 mmol/L, and x-ray of the chest and abdominal/pelvic ultrasound scan were normal. Excision of the mass was done and a tract was traced from the mass into the internal opening in the rectum and a connecting tract to the external opening at the 3 o'clock position. The tracts were laid open (fistulotomy) and a sigmoid end colostomy was done to divert faeces from the wound. Histological report of the excised gluteal mass revealed a well-differentiated adenocarcinoma probably from the rectum [Figure 2] and [Figure 3].
Figure 2: Residual ulcer 3 months after excision of the left gluteal mass

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Figure 3: Abdominoperineal resection of the rectum; wide local excision of the left gluteal wound done and fasciocutaneous flap raised from the right thigh to cover the defect

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The resulting wound granulated well on dressing [Figure 4]. The barium enema did not show any mass in the rectum. He subsequently had abdominoperineal resection (APR) of the rectum and wide local excision of the residual gluteal ulcer 3 months later. A fasciocutaneous flap was raised from the right thigh to cover the gluteal defect [Figure 5]. Histological examination did not reveal any malignant lesion in the excised rectum. He had several courses of 5-fluorouracil; he could not afford other chemotherapeutic drugs due to poor finances. Local tumor recurrence was noticed after 22 months of follow-up [Figure 6].
Figure 4: Adenocarcinoma lining part of the fistulous tract

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Figure 5: Adenocarcinoma lining and invading fistulous tract wall

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Figure 6: Local tumor recurrence 22 months after definitive surgery

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  Discussion Top

A rectal or anal carcinoma may present as a fistula-in-ano; carcinoma in a fistula-in-ano may also be due to seedling from a tumor elsewhere in the colon. It is difficult therefore, to determine that a carcinoma has arisen from a longstanding fistula-in-ano. Rossner [2],[3] stated three essential criteria to establish that a malignant transformation has occurred within a fistula: first, the fistula must have been present for 10 years to exclude the possibility of the malignancy having predated the fistula; second that there should not be any tumor within the mucosa of the rectum or anal canal unless there is a definite evidence that this is metastatic tumor; and third that the opening of the fistula within the anal canal or rectum should not contain malignant tissue. In this patient, the duration of the fistula was about 45 years, the barium enema done did not show any mass in the rectum, and the APR specimen (which included the internal opening of the fistula) was histologically free of tumor; therefore, all of Rossner's criteria were present in our patient.

Squamous carcinoma may develop due to chronic irritation/inflammation in a fistula-in-ano.[2],[4],[5] The origin of adenocarcinoma in an anorectal fistula is controversial. Jones and Morson [6],[7] in their study suggested that the fistulous tracts are congenital duplications of the lower end of the hindgut lined by rectal mucosa that is prone to malignant change to adenocarcinoma. Other origins can be chronic colitis and Crohn's disease with high inflammatory activity.[7],[8] Use of immunosuppressants and biological agents, e.g., infliximab and adalimumab in Crohn's disease may play an initiating or exacerbating role.[8]

Magnetic resonance imaging (MRI) is the imaging modality of choice in tumor arising within a fistula-in-ano. It may pick a mass and delineate the tracts between it and the anus. It may also prove the absence of a mass within the bowel lumen and pick regional lymph node enlargement.

Carcinoembryonic antigen (CEA) is a useful tumor marker in monitoring tumor recurrence and occurrence of metastases. Both MRI and CEA were neither readily available to nor affordable for our patient.

The acceptable treatment of malignancy originating from a fistula-in-ano is APR of the rectum with wide local excision of the perineal lesions.[1],[2],[7],[9],[10] This rather radical surgery advocated by all the authors is aimed at locoregional control of the disease as the course remains for a long period at the local and regional levels, with persistent perianal sepsis and risk of intestinal obstruction.

The role of additional chemotherapy/radiotherapy has been debated. While there is evidence that chemoradiotherapy improves survival, some authors prefer not to add chemoradiotherapy arguing that the prognosis is good after surgery alone if treated early, and that follow-up is sufficient.

Others advocate neoadjuvant chemo- and radiotherapy, noting that this increases the median survival for up to 3 years.[6],[7] Our patient had 5-fluorouracil as a sole chemotherapeutic agent as he could not afford other drugs; he did not have radiotherapy. Local tumor recurrence was noticed after 22 months of follow-up [Figure 6] during his last clinic visit but he had not shown any evidence of distant metastases and had a Karnofsky performance score of 80%. Lymph node metastases is mostly to the superficial inguinal or to the retrorectal lymph nodes; our patient does not have any palpably enlarged inguinal lymph node. Adenocarcinomas associated with fistula-in-ano are usually of the mucinous (colloid) histological type. Our patient had a well-differentiated histological grade, which has a good prognosis but also poor sensitivity to chemotherapy or radiotherapy. Prognosis depends on the size of the tumor, presence of metastases, and the histological grade. Prognosis is poor if the tumor is greater than 5 cm and it is good in well-differentiated tumors because they exhibit late metastases.

  Conclusion Top

Fistula-in-ano is not a completely innocuous disease and patients should be counseled to seek prompt and adequate treatment. Multiple biopsies of fistulous tracts should be taken during surgery and sent for histological examination. Malignancy associated with fistula-in-ano is best treated by APR of the rectum with wide local excision of the perianal lesions, with or without chemoradiotherapy; this leads to cure or long-time recession from the disease.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Itah R, Werbin N, Skornick Y, Greenberg R. Anal mucinous adenocarcinoma arising in long standing fistula-in-ano. Harefuah 2008;147:117-9, 183.  Back to cited text no. 1
Welch GH, Finlay IG. Neoplastic transformation in longstanding fistula-in-ano. Postgrad Med J 1987;63:503-4.  Back to cited text no. 2
Rossner C. Relation of fistula-in-ano to cancer of the anal canal. Trans Am Proc Soc 1934;65-70.  Back to cited text no. 3
Lynch J, Gross P. A case of carcinoma of the rectum associated with fistulae in ANO. Am J Cancer 1933;18:39-41.  Back to cited text no. 4
Kyzer S, Bayer I, Turani H, Chaimoff C. Verrucous squamous carcinoma as a complication of recurrent multiple perianal fistulae. Colo-proctology 1985;7:104-6.  Back to cited text no. 5
Jones EA, Morson BC. Mucinous adenocarcinoma in anorectal fistulae. Histopathology 1984;8:279-92.  Back to cited text no. 6
Venclauskas L, Saladzinskas Z, Tamelis A, Pranys D, Pavalkis D. Mucinous adenocarcinoma arising in an anorectal fistula. Medicina (Kaunas) 2009;45:286-90.  Back to cited text no. 7
Freeman HJ, Perry T, Webber DL, Chang SD, Loh MY. Mucinous carcinoma in Crohn's disease originating in a fistulous tract. World J Gastrointest Oncol 2010;2:307-10.  Back to cited text no. 8
Ong J, Jit-Fong L, Ming-Hian K, Boon-Swee O, Kok-Sun H, Eu KW. Perianal mucinous adenocarcinoma arising from chronic anorectal fistulae: A review from a single institution. Tech Coloproctol 2007;11:34-8.  Back to cited text no. 9
Schaffzin DM, Stahl TJ, Smith LE. Perianal mucinous adenocarcinoma: Unusual case presentations and review of the literature. Am Surg 2003;69:166-9.  Back to cited text no. 10


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]

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