The Importance of Near Follow-Up in Perianal Fistula

Anal canal mucinous adenocarcinoma constitutes 2-3% of anal canal tumors. It is very rare to see perianal fistula and anal canal mucinous adenocarcinoma (MA) together. The underlying pathophysiology leading to malignant transformation is still not clear. For MA to develop, the perianal fistula must be at least 10 years old, and this is one of the diagnostic criteria.¹,² However, Michihiro Koizumi et al. They revealed the existence of a perianal fistula-related MA with a 3-year follow-up.³

A sixty-three-year-old male patient was admitted to our clinic with anal discharge and palpable hardness in the anal canal while using the toilet. Perianal fistulas had been present for 3 years. In proctological examination, a mass appearance was observed in the anal canal close to the anal verge and 3 external fistula orifices were observed in the perianal region (Fig. 1). In magnetic resonance imaging, the anal canal wall thickness was increased. In addition, the inner mouth of the intersphincteric fistula was intertwined with the MA. Colonoscopy revealed that the tumor surrounded the anal canal in a circular manner. Pathology was reported as MA. CEA: 2.51 ng/mL, CA19.9: 5.37 U/mL were within normal values. After chemotherapy and radiotherapy, the patient underwent abdominoperineal resection (miles) and fistulectomy (Figs. 2 and 3).

Fig. 1
Fistula and Anal canal tumor.

Fig. 2
Fİstula tract.

Fig. 3
Miles and fistulectomy.

It is thought that it takes at least 10 years for anal canal tumor to develop in perianal fistula patients.¹ This may delay the early diagnosis of MA. Therefore, we recommend close follow-up and treatment of perianal fistula patients.

References

• ¹
  Tahir M, Rahman J, Zubair T, Basit A. An Association of Mucinous Adenocarcinoma With Chronic Peri-Anal Fistula: A Brief Review of Pathophysiology of Rare Tumor. Cureus 2020;12(06):e8882. Doi: 10.7759/cureus.8882
  » https://doi.org/10.7759/cureus.8882
• ²
  Prasad SN, Razik A, Siddiqui F, Lal H. Mucinous adenocarcinoma arising from chronic perianal fistula mimicking horseshoe abscess. BMJ Case Rep 2018;2018:bcr2017223063. Doi: 10.1136/bcr-2017-223063
  » https://doi.org/10.1136/bcr-2017-223063
• ³
  Koizumi M, Matsuda A, Yamada T, et al. A case report of anal fistula-associated mucinous adenocarcinoma developing 3 years after treatment of perianal abscess. Surg Case Rep 2023;9(01):159 https://doi.org/10.1186/s40792-023-01743-3
  » https://doi.org/10.1186/s40792-023-01743-3

Publication Dates

• Publication in this collection
  05 July 2024
• Date of issue
  2024

History

• Received
  03 Nov 2023
• Accepted
  09 Apr 2024