New surgical approach of retrorectal cystic hamartoma using transanal minimally invasive surgery (TAMIS)

Nova abordagem cirúrgica do hamartoma cístico retrorretal usando cirurgia transanal minimamente invasiva (TAMIS)

Abstracts

Introduction:

Tailgut cysts or cystic hamartomas are rare developmental tumors of the pre-sacral space. Their true incidence is not well known but we must think on it when we have a patient with a multicystic uncapsulated tumor at presacral space. Tailgut cysts are often asymptomatic, and in other cases present with chronic perineal pain, constipation or rectal tenesmus. They must be treated to avoid complications such as infections (perianal fistula or abscess) and malignant degenerations (usually adenocarcinoma).

Case report:

One patient with anal pain was diagnosed with a perianal abscess. He was operated but at the second month review a MRI revealed a multilocular lesion in the presacral suggesting the presence of a retrorectal cystic hamartoma.

An elective operation was performed by endoanal surgical approach using TAMIS. En bloc resection of the cyst was achieved with safe margins. The pathology result reported retrorectal cystic hamartoma. The patient was asymptomatic with no signs of recurrence in subsequent controls.

Our experience, despite being based on one case, is evidence that TAMIS (Transanal Minimally Invasive Surgery) allows a minimally invasive dissection with similar benefits as the use of TEM/TEO devices.

Cystic hamartoma; Tailgut cyst; Retrorectal tumor; Minimally-invasive surgical; procedures

Introdução:

Tail gut cysts ou hamartomas císticos são tumores raros de desenvolvimento do espaço pré-sacral. Sua verdadeira incidência não é bem conhecida, mas devemos pensarnele quando temos um paciente com um tumor uncapsulated multicística no espaço présacral. Hamartomas císticos são muitas vezes assintomáticas, em outros casos, apresentase com dor perineal crônica, constipação ou tenesmo retal. Eles devem ser tratados para evitar complicações, como infecções (fístula perianal ou abscesso) e degenerações malignas (geralmente adenocarcinoma).

Relato de Caso:

Um paciente com dor anal foi diagnosticado com um abscesso perianal. Ele foi operado, mas na revisão do segundo mês uma ressonância magnética revelou uma lesão multilocular no pré-sacral, sugerindo a presença de um hamartoma cístico retrorretal.

Uma operação eletiva foi realizada por abordagem cirúrgica endoanal usando TAMIS. A resseção em bloco do cisto foi conseguido com margens seguras. O resultado do exame patológico relatou hamartoma cístico retrorretal. O paciente encontrava-se assintomático, sem sinais de recidiva em controles posteriores.

A nossa experiência, apesar de ser baseado em um dos casos, as provas que TAMIS (cirurgia transanal minimamente invasiva) permite um esvaziamento minimamente invasivo com benefícios similares como o uso de dispositivos de MET/TEO.

Hamartoma cístico; Tailgut cyst; Tumor retrorretal; Procedimentos cirúrgicos; minimamente invasivos

Introduction

Retrorectal cystic hamartomas are rare congenital tumors derived from the regression of the tailgut, which normally regresses during the seventh or eighth week of the embryonic phase.¹

Most hamartomas are non-symptomatic retrorectal multicystic masses and usually appear in middle-aged women. Surgery is required to treat hamartomas. Multiple surgical approaches have been described, primarily due to location of the tumor and attendant difficulties.

We present a case of a retrorectal hamartoma cystic in a young male patient, who debuted with a perianal abscess and was surgically treated using a transanal approach. We conclude with an examination of clinical series and reviews found in the literature using the PubMed electronic database.

Case report

A 24-year-old male arrived at the emergency room complaining of anal pain that worsened over several months. He had previously received ambulatory care, where he was diagnosed with an anal fissure and treated symptomatically. Despite treatment, the patient continued to complain of anal pain.

The patient had been treated in the emergency room on two prior occasions. On the second occasion, he suffered from a 38 °C fever and anal incontinence, which progressed to liquid overnight.

On physical examination, the patient's abdomen was soft and painless; the DRE (digital rectal examination) was not possible because of pain.

A pelvic CT scan was reported as a heterogeneous hypodense image of 3 cm x 3 cm x 6 cm in the recto-sacrum space compatible with an over the levator ani muscle abscess (Fig. 1).

Fig. 1
Heterogeneous hypodense image in the recto-sacrum space compatible with abscess in pelvic CT scan.

The patient was diagnosed with a perianal abscess and decided to operate. Using an endoanal surgical approach, palpation discovered a fluctuating cystic mass on, and extracted a transparent, odorless and mucoid substance.

The patient was seen in consultation one week after surgery. Despite being feverless, the patient still complained of discomfort on defecation and tenesmus. Subsequent examinations were scheduled in order to continue the study.

At the second month review the wound was closed. An MRI revealed a multilocular lesion of 3 cm x 3.5 cm x 1.7 cm in the presacral space with hyperintense signal in T2 and hypointense signal in T1, suggesting the presence of a mucid content cyst (Figs. 2 and 3). These findings, along with the information obtained during the previous surgery, led us to consider whether the patient suffered from a retrorectal cystic hamartoma.

Fig. 2
MRI revealed a multilocular cystic mass in the presacral space.

Fig. 3
Sagittal T2-weighted magnetic resonance scan suggested the presence of a mucid content cyst.

An elective operation was performed. Given the previous history, we chose an endoanal surgical approach using TAMIS (Fig. 4). En bloc resection of the cyst was achieved with safe margins. The pathology result reported retrorectal cystic hamartoma (Fig. 5). The patient was discharged on the second day following the operation, and was asymptomatic with no signs of recurrence in subsequent controls.

Fig. 4
Endoanal surgical approach using TAMIS (Transanal Minimally Invasive Surgery).

Fig. 5
The pathology result reported different types of epithelia without crypts or villi surrounded by a discontinuous muscle layer.

Discussion

Retrorectal tumors

The Pre-sacrum or retrorectal space is located between the rectum, the pre-sacrum fascia, the lateral ligaments, the peritoneal reflection, and the Waldeyer fascia. It usually contains structures derived from neuroectoderm, notochord, gut and embryological remnants.

The true incidence of embryonary tumors in the retrorectal space is not known because reported findings tend to be incidental to findings of asymptomatic lesions.

Predominance in females has been subject to considerable debate, with some claims that this finding could be due to regular gynecological and pelvic examinations.²,³

These tumors are mostly inflammatory lesions and developmental cysts,⁴ but in this group we also find cystic hamartoma.

Tailgut cysts

The tailgut cyst or cystic hamartoma is a tumor of the presacral space that was first described in 1885 by Middeldorf.⁵ They derived from an embryonic remnant of the primitive bowel, as Hjermstad et al. postulated in the largest case review done to date.⁶ If Hjermstad is correct, the anal margin merges with the primitive gut (tailgut) above its distal end. The outcome of this merger is a bag with squamous cubical epithelium in the presacral space.¹,⁷ Normally, this vestige regresses during embryonic development, but when this does not happen, a cystic hamartoma appears.

Patient symptoms vary and are related to the location, size, mass, and therefore infections of the cyst. Most tailgut cysts are asymptomatic findings during a clinical examination for other reasons (CTscan, MRI, Endorectal ultrasound, etc.) For some authors, 50% of hamartomas present with chronic perineal pain, constipation, rectal tenesmus (as we present in our case report), rectal bleeding or urinary rate changes. Fever, or signs of perianal suppuration in the perineum, suggests fistula, abscess and complications from cyst infection.⁶,⁸,⁹ This is why many patients are diagnosed from retrorectal abscesses or from multiple interventions for recurrent perianal fistula.

Diagnosis

On physical examination, most patients have palpable mass on DRE, which is a key consideration for any diagnosis. There is a sensibility that varies between 97%¹⁰ and 75%² described for the DRE. In our case, the clinical picture debuted as a complication of infection that led to an initial misdiagnosis of a high perirectal abscess. Rectal examination was painful and whitish content oriented to the suspected diagnosis. A colonoscopy allowed examination of endoluminal injury, but barium enema was ineffective as no additional information is given. Imaging tests can sometimes be helpful, because the presence of a multicystic tumor, circumscribed and uncapsulated at a presacral space level, leads to cystic hamartoma diagnoses as well. Within imaging tests we described the use of endoscopy, MRI or CT and eco-endoanal⁴; endoanal ultrasound is not useful. It only allows identification of the nature of the cyst (jelly type or watery type) and its relation to the surrounding areas.¹¹

The CT shows a mass with clear edges and reveals liquid or soft tissue content. One rarely finds calcifications inside the thin wall.¹¹ In the case of a complicated cyst due to infection or malignization, we usually find uneven margins.¹,¹¹

The MRI imaging is important to determine the multiple cyst character of the tailgut and its relation to the adjacent structures. Typically the cyst will be hypointense in T1w and hyperintense in T2w sequence, and heterogeneous content can also be seen resulting from the mucine, proteic material or intracystic hemorrhage.¹¹-¹³ The T2 sequence of a cyst showing tracts inside is also characteristic of a hamartoma, as Kim et al. describes and similar to our case.¹² Another finding is the presence of a little peripheral cyst accompanying the hamartoma.⁷ It is important to determine the unior multi-lobular nature of the cyst because this establishes the differential diagnosis between hamartoma or multilocular cystic lymphangioma versus other pre-sacrum cysts.

In any event, we should avoid the biopsy of the lesion because of a high risk of its local dissemination and its low outcome for diagnosis confirmation.

In our case, we drained the cyst through the anal lumen which did not avoid the lesion's reproduction two months later.

Once the surgical piece has been processed, pathology will show different types of epithelia without crypts or villi surrounded by a discontinuous muscle layer (Fig. 5). Super-infected cysts usually present wall fibrosis and loss of definition in the epithelial lining.

Treatment

Treatment is based on complete resection of the lesion to avoid recurrence, infection or malignant degeneration.

The approach to the retrorectal space is latero-sacral, abdominal or perineal.

The latero-sacral parasacrococcigeal approach is the most used one, because it allows a good exposition of the anus and the levator ani muscle plan.

The abdominal approach, either laparotomy or laparoscopy, is indicated only when large tumors are present or if the tumors grow upwards instead of downwards toward the pelvic area. The abdominal laparoscopic approach gives us the advantage of a finer mesorectum dissection. The perineal access is done with the patient in lithotomy position. Incision is performed on the perineal raphe to reach the retrorectal space. However all of these techniques have a high rate of morbidity.¹⁴,¹⁵

In the past few years, the use of endoanal procedures using TEM/TEO devices has increased to avoid morbidity.³,¹⁶-¹⁸However accessibility to these devices is restricted because of high cost and difficult learning curves.¹⁹

The TAMIS (Transanal Minimally Invasive Surgery) achieves similar benefits as the use of TEM/TEO devices.²⁰ TAMIS uses a single site device, like SILS (Covidien), which is lubricated and located in the anal canal manually. It has three sites where we can introduce two 5 mm and one 10 mm trocars (Fig. 4). The CO₂ gas goes through the single site device cannula, being careful not to exceed 18 mm Hg. In our series we use a 5 mm and 30 grades angulated optic and conventional laparoscopic material.

Both techniques try to reach a reasonable resection with the least amount of damage possible.

In this way, TAMIS has proven to be a reliable alternative to TEM/TEO with the same benefits at a lower coast.

Conclusions

The tailgut is a tumor located in the presacral space. We must think of it as a perianal abscess with atypical characteristics. It can be complicated with perianal chronic fistula or malignization, underscoring the importance of complete resection. For this approach, several techniques have been described here. We conclude that TAMIS allows a minimally invasive high-quality dissection at a lower cost when compared to TEM.

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Publication Dates

• Publication in this collection
  Oct-Dec 2014

History

• Received
  15 Mar 2014
• Accepted
  11 Aug 2014