Endoanal Ultrasonography of Mucinous Adenocarcinoma Arising from Chronic Fistula-in-ano: Three Case Reports

Abstract

Abstract:Mucinous adenocarcinoma arising in chronic fistula-in-ano is rare, and diagnosing it at an early stage is difficult. The role of endoanal ultrasonography in diagnosing the condition has not been discussed in the study. Herein, we report three cases of mucinous adenocarcinoma arising from anal fistulas in which endosonography played an important role in diagnosing malignant change. Three male patients with a 5-to 20-year history of anal fistula were referred to our hospital due to perianal induration, progressive anal pain, or mucopurulent secretion. In all three patients, endosonography revealed a multiloculated complex echoic mass with isoechoic solid components communicating with a trans-sphincteric fistula and sonographyguided biopsy under anesthesia revealed mucinous adenocarcinoma. All patients underwent abdominoperineal resection with lymph node dissection. One patient with a local recurrence died 3 years after surgery and two have remained disease-free for >6 years. These observations suggest that endosonography may be a reliable technique for the diagnosis of mucinous adenocarcinoma arising from chronic fistula-in-ano. Sonography-guided biopsy is useful for the definitive diagnosis of malignancy. Therefore, periodic endosonography assessment should be recommended for patients with persistent anal fistula, especially those with progressive clinical symptoms. Once malignancy is suspected, aggressive sonography-guided biopsy under anesthesia should be performed, which may enable an early diagnosis, curative treatment, and favorable long-term results.

An Association of Mucinous Adenocarcinoma With Chronic Peri-Anal Fistula: A Brief Review of Pathophysiology of Rare Tumor

“…The study summed up three criteria needed for the diagnosis of MA: (1) the presence of fistula ought to usually precede that of carcinoma by 10 years, (2) any tumorous association of the rectum or anal canal should only be a secondary extension of the primary mass involving the fistula, and (3) internal opening of the fistula within the rectum or anal canal should not be included, as shown in Figure 4 Toyonaga et al showed the significance of EAUS of MA arising from chronic peri-anal fistula. The study demonstrated a typical pathology of MA with multiloculated complex echoic mass along isoechoic solid components communicating with a trans-sphincteric fistula, as shown by a sonography-guided biopsy under anesthesia [23]. Another study was conducted by Papaconstantinou et al which reported the root of the MA within a chronic peri-anal fistula in Crohn's disease.…”

“…The biologic importance of MC of the colon and rectum continued to be contentious [30,31]. Overall, the prognosis of the patients diagnosed with colorectal MC is worse [23].…”

“…In this manner, regular evaluation with EAUS ought to be suggested for patients with long-standing peri-anal fistula, particularly those with dynamic clinical manifestations. Once the malignancy is suspected, vigorous sonography-guided biopsy under anesthesia should be carried out, which may empower the early findings, treatment, and favorable long-term benefits [ 23 ].…”

“…Toyonaga et al showed the significance of EAUS of MA arising from chronic peri-anal fistula. The study demonstrated a typical pathology of MA with multiloculated complex echoic mass along isoechoic solid components communicating with a trans-sphincteric fistula, as shown by a sonography-guided biopsy under anesthesia [ 23 ]. Another study was conducted by Papaconstantinou et al which reported the root of the MA within a chronic peri-anal fistula in Crohn’s disease.…”

Perianal mucinous adenocarcinoma with dysplastic polyps of the colon: A case report

“…Positron Emission Tomography (PET) has limited use for the diagnosis, because there is a negative correlation between the amount of mucin present and tumor fluorodeoxyglucose (FDG) uptake [ 12 ]. Finally, endoanal ultrasonography (EUS) has been suggested in patients with recurrent fistulas, to find the malignant lesion and to better guide tissue biopsy [ 13 ]. Histopathological study is mandatory to rule out malignancy.…”