Published: 2019-10-24

Mucinous adenocarcinoma within an anal fistula in a patient with Crohn’s disease

María Riaza Montes, Unai De Andrés Olabarria, Izaskun Badiola Bergara, Vicente Portugal Porras, Francisco Javier Ibáñez Aguirre


Anal mucinous adenocarcinoma is a rare entity, representing approximately 5-11% of all anal cancers. Sometimes it is associated with chronic inflammation of long-standing anal fistula as it may occur in patients with Crohn's disease. In this case, cancer usually goes unnoticed owing to the inflammatory disease; therefore, a degree of uncertainty surrounds initially the diagnosis. We report a case of a 62-year-old man with A2 L3 B3p Crohn’s disease who also presents a perianal mucinous pseudocyst that is removed. Histological examination reveals a mucinous pseudocyst. At the two-year follow-up, we observe the recurrence of the cyst within an anal fistula. Scheduled non-oncologic surgery is performed with resection of the cyst and tutoring of the fistula with seton. Histological examination reveals mucinous adenocarcinoma. With no evidence of metastasis in the extension study, the patient is subjected to radical surgery with abdominoperineal resection. After 3 years and 11 months, a follow-up is carried out and there is no evidence of recurrence or distant metastasis. Mucinous adenocarcinoma within an anal fistula is a challenge in its diagnosis and its treatment due to the anecdotal nature of the cases. Given the high local risk of recurrence, radical surgery is recommended, occasionally associating neoadjuvant chemoradiotherapy if the neoplasm is locally advanced.



Mucinous adenocarcinoma, Crohn disease, Anal fistula, Neoadjuvant therapy

Full Text:



Scharl M, Frei P, Frei SM, Biedermann L, Weber A, Rogler G. Epithelial-to- mesenchymal transition in a fistula-associated anal adenocarcinoma in a patient with long-standing Crohn’s disease. Eur J Gastroenterol Hepatol. 2014;26(1):114–8.

Chrysikos D, Mariolis-Sapsakos T, Triantafyllou T, Karampelias V, Mitrousias A, Theodoropoulos G. Laparoscopic abdominoperineal resection for the treatment of a mucinous adenocarcinoma associated with an anal fistula. J Surg Case Reports. 2018;3:36.

Alvarez-Laso CJ, Moral S, Rodríguez D, Carrocera A, Azcano E, Cabrera A, et al. Mucinous adenocarcinoma on perianal fistula. A rising entity? Clin Transl Oncol. 2018;20(5):666–9.

Santos MD, Nogueira C, Lopes C. Mucinous adenocarcinoma arising in chronic perianal fistula: good results with neoadjuvant chemoradiotherapy followed by surgery. Case Rep Surg. 2014;2014:386150.

Purkayastha A, Sharma N, Dutta V, Bisht N, Pandya T. Mucinous adenocarcinoma of perianal region: an uncommon disease treated with neo- adjuvant chemo-radiation. Transl Gastroenterol Hepatol. 2016;1:52.

Borpujari PJ, Bhargava S. Unusual presentation of mucinous adenocarcinoma in a post fistulectomy case. Med J Armed Forces India. 2015;71(Suppl 1):S111-3.