Malignant transformation of tailgut cysts is significantly higher than previously reported: systematic review of cases in the literature

Abstract

Aim The best treatment for tailgut cysts has not been firmly established. We report a systematic review of the cases in the available literature in order to provide an evidence base for treatment. Method A systematic search of articles wholly or partly in English was made of PubMed, Embase and Google Scholar; additional studies were discovered by searching reference lists and contacting authors directly. Search terms ‘tailgut cyst’, ‘tail gut cyst’, ‘retrorectal hamartoma’ and ‘retrorectal tumour’ were used for case reports or case series; no publication date restrictions were imposed. Only studies with histological confirmation of diagnosis and reporting the age and gender of patients were included. Papers were excluded by consensus between the first two authors. Results A total of 196 individual cases were analysed in detail including 51 cases of neoplasia. The overall rate of neoplastic transformation was 26.6%. Although the male:female cyst incidence ratio was 1:4, men over 18 had a significantly greater relative risk of neoplasm at 1.94 (P = 0.0055). Radiological evidence of nodular thickening of the cyst wall significantly increased the relative risk of the presence of cancer (P = 0.0023). Conclusions Current orthodoxy that these are not dangerous embryological remnants is unfounded and may be false. The available data suggest the risk of malignant transformation is high and will apply to any residual tissue after excision. The same rationale behind total mesorectal excision in rectal cancer applies to tailgut cysts. Consequently they should be resected with similar oncological margins.

Tailgut cyst with adenocarcinoma transition

“…[ 1 ] TGC is common in adult women and the ratio of female to male patients is 3:1 to 4:1. [ 2 ] TGCs are often located in the space behind the rectum and ahead of the sacrum. In addition, the upper boundary of the space is the peritoneal reflex; the lower boundary is the levator ani muscle; and the bilateral boundaries are the bilateral ureters, iliac vessels, and sacral nerve roots.…”

Mucinous adenocarcinomas arising from a retro-rectal hamartoma: Unusual malignant transformation of a tailgut cyst

“…In a review of the scientifi c literature, malignant transformation within a retrorectal cyst hamartoma has only been documented in 33 cases (including the current report), carcinoid tumor and adenocarcinoma included in the search [8,9], while there have been found 29 cases of neuroendocrine tumours arising in tailgut cysts [10,11].…”

Retrorectal Mucinous Adenocarcinoma Arising from a Tailgut Cyst: A Case Report

“…In cases of malignant transformation, imaging and particularly MRI is of major importance; transformation may be suspected on MRI in view of cystic nodular wall thickening [2], usually heterogeneous, with irregular margins, solid areas, and gadolinium enhancement [4]. Histologically, although adenocarcinomas are the most frequent histological types, neuroendocrine carcinomas, transitional cell carcinomas, sarcomas, or squamous cell carcinomas have also been observed and these different epithelia often coexist [2, 6]. In our case, the retrorectal cyst had malignant degeneration mainly on the anterior wall and had invaded the anal sphincters and perianal skin.…”

“…Surgical treatment is necessary because of the risk of complications including recurrent perianal suppuration and malignant transformation [1]. The rate of malignant transformation is poorly understood but seems higher than initially estimated [2]; these are usually mucinous adenocarcinoma but can be transitional cell carcinoma, carcinoid tumors, or squamous cell cancers. We report the case of a 57-year-old woman who, perhaps for years, had been losing a small amount of mucoid fluid from a small sus-anal opening, and who experienced anal discomfort revealing retroanal mucinous adenocarcinoma invading her anal sphincter and developing on a tailgut cyst.…”