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

Perianal Mucinous Adenocarcinoma Found Incidentally From Perianal Mass

Anal mucinous adenocarcinomas are very rare and usually arise from anal fistulas. We report a case of a 73-year-old man with a past medical history of hypertension admitted to our facility for evaluation of bleeding from a large, tender, left gluteal perianal mass. The patient reported the mass had been growing for over six years. On examination, an ulcerated, fungating large exophytic lesion was found extending from the anal verge laterally engulfing the left gluteus. The patient was anemic with low hemoglobin and hematocrit, as well as an elevated carcinoembryonic antigen level. A colonoscopy was performed during which an internal opening of a left-sided anal fistula was identified. The mass was biopsied and returned positive for a mucinous adenocarcinoma. Staging imaging including a computed tomography scan of the chest abdomen and pelvis did not show any metastatic disease. A magnetic resonance image of the pelvis revealed a locally invasive, heterogeneous tumor extending from the perianal soft tissue to the posterior wall of the anal canal and lower rectum. The patient was discussed at the interdisciplinary tumor board and completed five weeks of concurrent chemotherapy and radiation with 5-fluorouracil and a total of 28 fractions of radiation. He then underwent abdominoperineal resection with a vertical rectus abdominis myocutaneous flap. The patient was placed in the surgical intensive care unit and subsequently discharged in stable condition on postoperative day 14. This case highlights the presentation, diagnosis, and management of anal mucinous adenocarcinoma.

Adjuvant chemoradiotherapy does not improve outcomes in patients with fistula-associated anal adenocarcinoma undergoing abdominoperineal resection

OBJECTIVE

Abdominoperineal resection (APR) is currently established as a standard treatment regimen for fistula-associated anal adenocarcinoma (FAAA), however, the efficacy of chemoradiotherapy (CRT) remains unclear. The aim of this study is to evaluate the role of CRT in patients with FAAA treated with APR through single-center experience and literature review.

METHODS

A retrospective review was performed on patients with FAAA consecutive treated in our institution from 2005 to 2022. In addition, a systematic literature search was performed using PubMed and MEDLINE. All patients with FAAA who received APR in our institution and reported in the literature were included and divided into three categories for statistical analysis: APR alone (APR group), neoadjuvant therapy combined APR (CRT+APR group), and APR combined postoperative therapy (APR+CRT group).

RESULTS

Fifteen patients with FAAA were identified from our retrospective charts review. At a median follow-up time of 18 months, the recurrence-free survival rate was 53.3% and the survival rate was 73.3%. Eight patients underwent APR and 6 received postoperative chemotherapy. Among them, one died, one developed recurrence and the remaining six patients were alive with disease free. We found 37 publications describing 62 patients with FAAA treated with APR. Clinical data from these articles were analyzed together with the 8 cases in our institution. The overall survival rates were 94.1%, 70.8%, and 38.5% at 1-, 3-, 5-years respectively. Combining (neo)adjuvant therapy did not appear to improve outcomes in FAAA treated with APR (CRT+APR vs. APR, p=0.977; APR+CRT vs. APR, p=0.351). Lymph node involvement was shown to be significantly associated with poor outcomes by multivariate analysis (p=0.020).

CONCLUSIONS

For patients with FAAA without lymph node involvement, APR is adequate to control disease and the addition of CRT does not appear to prolong survival.

ACR Appropriateness Criteria® Anorectal Disease

This review summarizes the relevant literature for the selection of the initial imaging in 4 clinical scenarios in patients with suspected inflammatory disease or postoperative complication of the anorectum. These clinical scenarios include suspected perianal fistula or abscess; rectovesicular or rectovaginal fistula; proctitis or pouchitis; and suspected complication following proctectomy, coloproctectomy, or colectomy with a pouch or other anastomosis. The appropriateness of imaging modalities as they apply to each clinical scenario is rated as usually appropriate, may be appropriate, and usually not appropriate to assist the selection of the most appropriate imaging modality in the corresponding clinical scenarios of anorectal disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

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

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Mucinous adenocarcinoma of the perianal region is extremely rare (6.9% of anal neoplasms and 2–3% of all gastrointestinal malignancies).

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Given the low incidence of this tumor, it is often missed at initial evaluation.

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Association with chronic perianal fistula are common and inflammatory symptoms can be misleading with delay in diagnosis.

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The paucity of publications leads to a lack of consensus on both diagnostic and therapeutic approaches.

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The understanding of the etiopathogenic mechanisms may lead to the development of novel diagnostic and therapeutic protocols.

Introduction

Perianal mucinous adenocarcinoma is rarely encountered in the setting of anal neoplasms. The rarity of the disease and the paucity of publications on this topic are responsible for a lack of diagnostic and therapeutic guidelines.

Presentation of case

An 80-year-old man with mucinous adenocarcinoma of the anal canal associated with dysplastic polyps of the colon was treated by multiple endoscopic polypectomies and abdomino-perineal resection of the rectum. We discuss the management of this rare case from the diagnosis up to one-year follow-up.

Discussion

Perianal mucinous adenocarcinoma is a very rare entity frequently combined with chronic fistulas. Inflammatory symptoms may mislead its diagnosis, which is often delayed. The unique association between perianal mucinous adenocarcinoma and dysplastic polyps of the colon, that we have reported, may suggest a secondary etiology. High clinical suspicion is important for early and correct diagnosis, which should be based on endoanal ultrasound and/or magnetic resonance imaging followed by deep tissue biopsies.

Conclusion

We stress the importance of accumulating such cases in the literature. The understanding of the etiopathogenic mechanisms may lead to the development of novel diagnostic and therapeutic protocols.

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

An anal fistula is a condition that has been discussed by various authors without coming to a consensus. The fistula of the anus is a passage that leads from the rectum to the anus. A peri-anal adenocarcinoma is an abnormal growth of cells in the anal rectal area. Establishing the relationship between the two, a lot of information was obtained from the existing literature which has used to come up with solutions to the objective of the study. The review was conducted systematically and included observational retrospective, case studies, and case series to demonstrate the data of valuable research. The articles were searched in PubMed, MEDLINE, and Google scholar using the keywords “chronic perianal fistula”, “anal carcinoma”, “mucinous adenocarcinoma”, and “perianal mucinous adenocarcinoma”. Among 50 journal articles, we chose 33 studies describing the clinical sign and symptoms, pathophysiology, etiology, and association between mucinous anal adenocarcinoma and chronic peri-anal fistula. After quality assessment, eight case studies and series were selected, in which seven of them showed the origin of mucinous anal adenocarcinoma from chronic peri-anal fistula. The existence of a long history of fistula-in-ano and the exclusion of any additional carcinoma in the body necessitates the analysis of mucinous adenocarcinoma arising from benign fistula. Likewise, the presence of fistula ought to typically precede that of carcinoma by 10 years, and this is one of the criteria for diagnosis. However, more investigation should be conducted to gain full information about the connection between these two entities.