Neuroendocrine Tumour Developing Within a Long-Standing Tailgut Cyst

Clinical Journal of Gastroenterology (2019) 12:539–551 https://doi.org/10.1007/s12328-019-00998-4

CASE REPORT

Neuroendocrine tumour developing within a long‑standing tailgut cyst: case report and review of the literature

Alice Lee1 · Thomas Surya Suhardja1,2 · Thang Chien Nguyen1,2 · William Meng‑Keat Teoh1,2

Received: 22 February 2019 / Accepted: 22 May 2019 / Published online: 30 May 2019 © Japanese Society of Gastroenterology 2019

Abstract A tailgut cyst is a rare congenital lesion that can develop in the presacral space from the remnants of an embryonic hindgut. It is unusual for malignant change to occur in a tailgut cyst. We report a case of a large long-standing tailgut cyst, which was removed during a laparotomy. Histopathology showed a well-diferentiated neuroendocrine tumour (primary carcinoid tumour) arising in a tailgut cyst. We reviewed the English literature for all adult cases with this condition. All original articles were reviewed, and data were compiled and tabulated. Including this report, 29 cases of NET developing in a tailgut cyst were found in the English literature. Tailgut cysts have been reported as more common in females, with a mean age of presentation in the ffth decade (Devine, in: Zbar A, Wexner S (eds) Coloproctology. Springer specialist surgery series, Springer, London, 2010; Hjermstad and Helwig in Am J Clin Pathol 89:139–147, 1988). Tailgut cysts may undergo malignant change including adenocarcinoma, sarcoma, and NET (Mathis et al. Br J Surg 97:575–579, 2010; Messick in Dis Colon Rectum 61:151–153, 2018; Patsouras et al. in Colorectal Dis 17:724–729, 2015; Chereau et al in Colorectal Dis 15:e476–e482, 2013). It is difcult to estimate the true incidence of malignant change in a tailgut cyst, with the literature reports only limited to case reports and small-case series. Although rare, our case confrms need to consider the possibility of a malignant component, even in a benign process such as a tailgut cyst. This prompts consideration for upfront defnitive management.

Keywords Neuroendocrine · Tailgut cyst · Presacral cyst

Introduction refection superiorly, the perineal muscles inferiorly, and the iliac vessels and ureters laterally [2, 7, 9, 10]. Other retro- A tailgut cyst is a rare benign congenital lesion that can rectal tumours include teratomas, duplication, neuroenteric, develop in the presacral space from the persistent remnants dermoid, and epidermoid cysts. of an embryonic hindgut [2, 7]. A tail exists in the human Lesions in the presacral space can be cystic or solid, embryo at the gestational age of 28–35 days. It has been and can cause symptoms such as abdominal pain, urinary hypothesised that the development of a tailgut cyst is due to symptoms, menstrual issues, constipation, and anorectal an incomplete regression of the tail extension of the hindgut discomfort. There are at least 25 diferent histologic types by about the eighth gestational week. Most of the literature of presacral lesions reported, and over half carry malignant has described the presence of tailgut cysts mainly in middle- diagnoses [11]. Congenital tailgut cysts are the most fre- aged women [2, 7, 8]. The presacral space is a potential quent presacral tumour type. It is rare for malignant transfor- space delineated by the rectum anteriorly, the presacral fas- mation (such as neuroendocrine tumour (NET), carcinoma, cia (Waldeyer fascia) and sacrum posteriorly, the peritoneal or adenocarcinoma) to occur in the presacral space; they are most often associated with tailgut cysts when they occur here [12]. It is thought that NET developing in the presacral * Thomas Surya Suhardja [email protected] space could be secondary to direct extension or metastatic invasion of a primary rectal malignancy [13]. 1 Colorectal Surgery Unit, Monash Health, Dandenong We present a rare case of NET within a tailgut cyst with- Hospital, 135 David Street, Dandenong, VIC 3175, Australia out evidence of a primary tumour source or metastatic dis- 2 Department of Surgery, School of Clinical Sciences ease. It was also unique that the cyst has been long-standing at Monash Health, Monash University, Clayton, VIC 3168, for many years, thus surmising the possibility of a rare Australia

Vol.:(0123456789)1 3 540 Clinical Journal of Gastroenterology (2019) 12:539–551 malignant change from an otherwise benign process. We 30%) patients underwent a pre-operative biopsy, which was also reviewed the English literature for all reported cases of diagnostic of NET. tailgut cyst with particular attention to any incidental NET All patients except one underwent surgery; one received on histopathology. pre-operative treatment (chemotherapy) prior to surgical resection. NET grade from Ki-67 proliferation indexing was reported in 16 cases (all in publications after 2005); Methods there were eight (8/16; 50%) low- and eight (8/16; 50%) intermediate-grade NET on histology. There was no standard approach for the presacral excision, with various methods A review of the literature a MEDLINE search for cases of described or it was not detailed. It was difcult to determine NET arising in a tailgut cyst was undertaken. All original the largest NET resected as not all reports specifed the size articles were reviewed, and data were compiled and tab- of NET from histological examination versus the size of the ulated qualitatively. The keywords search comprised of excised cyst. Five (5/27; 19%) patients had post-operative “neuroendocrine” or “carcinoid” tumour, and “retrorectal”, treatment including chemotherapy and/or a somatostatin “tailgut” or “presacral” (and related linkage terms) cyst. analogue. Mean follow-up time was 23.7 months (range The articles were reviewed to only include publications that 3–79 months). Two (2/27; 7%) patients had post-operative reported cases of NET arising in a tailgut cyst. Cases for recurrence of the NET. Six (6/27; 22%) patients were found inclusion were those in the English language and involving to have metastases not seen pre-operatively. patients aged 19 years and older. Patient age, gender, evidence of sacral/coccyx invasion, pre-operative biopsy, management via surgical resection, grade of tumour, Ki67 index, Case report evidence of metastases (pre- and post-operative), follow-up time, and management were recorded where available. NET A 33-year-old woman originally from Afghanistan initially grading was scored using the WHO classifcation system presented with a history of intermittent lower abdominal [14]. pain and dysmenorrhoea. Previous pelvic ultrasounds had described polycystic ovaries but no abnormal pelvic masses. The patient had no signifcant past medical history and there Review of the literature was no known family history of malignancy. A further pelvic ultrasound then noted a large solid and avascular mass in the Including this report, 29 cases of NET developing in a tail- left adnexa. A CT scan confrmed a large hypodense mass of gut cyst were found in the English literature. The character- maximal diameter 11.1 cm within the presacral space that istics of the cases are tabulated in Table 1. Two papers [3, appeared extra-ovarian in origin, closely abutting the right 5] did not provide any information aside from the age range lateral rectal wall, and posterior to the uterus and vagina. and/or gender of the patient, and thus were not included. She underwent a diagnostic laparoscopy by the gynaecol- There was a greater proportion of females (17/27; 63%) ogy unit, which demonstrated a frm 10 cm retroperitoneal having NET developing within tailgut cysts when compared presacral mass separate from the uterus and bilateral ovaries, to males (10/27; 37%). The average age of females was with apparent displacement of the rectum. No biopsies were 40.8 years (range 19–73) and 54.6 years for males (range taken at this time. Given its location and relationships, the 35–68). The diagnostic imaging modality most utilised for mass was deemed as not gynaecological in origin. She was visualisation of the presacral cyst was computed tomogra- referred to another unit for consideration of surgical manage- phy (CT), which was used in 15 of 23 cases (65%) with ment, but declined intervention at that time. Serial imaging information available; however, it was not always the frst (via ultrasound and CT scanning) was otherwise performed, investigation depending on the clinical situation. There were with lack of interval growth and a stable septated appear- various presenting symptoms related to the development of a ance, with scalloping of the adjacent sacrum suggesting a tailgut cyst, including pain (abdomen, pelvic, hip, back, and chronic process. anal), bowel changes (diarrhoea and constipation), urinary Eight years after her initial presentation, she was tract issues (recurrent infections and retention), and lower referred to our Colorectal unit with a recurrence of her limb neurological symptoms. Two (2/27; 7%) patients were central abdominal pain, which causing more discomfort diagnosed with a presacral cyst in an acute setting. Three on the right side compared to the left. She had no symp- (3/27; 11%) patients were known to have metastases prior toms of obstruction, but described occasional dysuria. to surgical resection of the tailgut cyst. Ten (10/27; 37%) MRI characterised the mass as a complex cystic mass con- patients had sacral or coccyx involvement. Three (3/27; taining an internal foci of fat signal measuring 1.8 cm in 11%) patients had pre-operative metastases. Eight (8/27; diameter anteroinferiorly (Fig. 1a–c). The posterior margin

1 3 Clinical Journal of Gastroenterology (2019) 12:539–551 541 - chemo failed therapy Surgical resection Surgical Yes Yes - post Yes—1-year Yes Yes Yes Yes Yes Yes No Yes Yes lesion and liver lesion and liver metastasis Pre-operative Pre-operative biopsy No No No No NA Yes NA NA No Yes—of presacral presacral Yes—of No Yes chromogranin A chromogranin Tumour markers Tumour NA NA Normal NA NA NA NA NA Normal Elevated serum Elevated Normal NA nodes, muscle, bone Pre-operative Pre-operative metastases No No No No No NA No No No Yes—liver, lung, Yes—liver, No No Sacral or coc - Sacral cyx invasion Yes No Yes No No Yes Yes Yes No Yes No No suspected sacral suspected sacral metastasis); MRI; angi - CT; (with ography pre-operative embolisation) copy only copy FGD PET Imaging Bone scan (for Bone scan (for U/S Nil U/S CT CT CT NA - None—sigmoidos CT; MRI CT; CT, MRI, 18F- CT, CT; MRI CT; sister with sister meningocoele Family history Family NA Presacral masses; Presacral NA NA NA NA NA NA NA NA NA No - - bladder and hydronephrosis; transurethral - resec prostate tion (benign); partial- gastrec peptic for tomy ulcer disease tomy (20 years (20 years tomy prior) disease; hyster uter for ectomy ine leiomyoma Past medical Past history Neurogenic Neurogenic NA NA NA NA NA Haemorrhoidec - NA Nil Nil Nil Peripheral vascular Peripheral vascular during workup for during for workup disease prostate menstrual cycles ments and mild rectal bleeding (12 months) and pain extending and pain extending the left leg, down and a prominent on tender bulge the left buttock (3 years) increasing over 1 over increasing and associ - year ated with mucous discharge perianal pain back pain with back left leg irradiation (2 years) irregular mucus emission (few months) Presenting symptoms Presenting Sacral mass detected mass detected Sacral Pelvic pain, irregular Pelvic Acute abdominal pain Acute Pelvic pain Pelvic - move bowel Painful Diarrhoea, numbness Anal pain (3 years), Anal pain (3 years), NA Acute presentation— Acute Increasingly severe severe Increasingly Rectal fullness and Rectal Left hip pain (3 years) Sex M F F F F M M F F M F F 61 19 19 21 69 52 68 42 41 37 49 51 Age 1994 1998 2000 2000 2003 2004 2004 2005 2005 2008 Years Previous cases of NET developing in a tailgut cyst cases of NET developing Previous [ 20 ] 1 Table References Schnee et al. [ 19 ] et al. Schnee Horenstein et al. et al. Horenstein Prasad et al. [ 7 ] et al. Prasad Oyama et al. [ 12 ] et al. Oyama Mourra [ 21 ] et al. Jacob et al. [ 22 ] Jacob et al. Song et al. [ 23 ] Song et al. Luong et al. [ 24 ] et al. Luong Mathieu et al. [ 25 ] Mathieu et al. Liang et al. [ 26 ] Liang et al.

1 3 542 Clinical Journal of Gastroenterology (2019) 12:539–551 Yes Yes Yes Surgical resection Surgical Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes No NA Yes Pre-operative Pre-operative biopsy NA No Yes No No No No Yes Yes Yes specifc enolase Normal NA NA Tumour markers Tumour NA Normal Elevated neuron- Elevated Elevated CA19-9 Elevated Normal NA Normal Normal NA Normal Yes—liver NA No Pre-operative Pre-operative metastases No No No No No No No No No No No NA Yes Sacral or coc - Sacral cyx invasion Yes No No No No Yes No No No Yes - 111-Octreo In tide scintigraphy PET/CT (for PET/CT (for metastases) MRI colonoscopy colonoscopy with EUS; OctreoScan scintigraphy MRI; 18F-FDG PET/CT MRI; CT; NM MRI; CT; ruleMIBG (to out metastases) Ga-DOTATATE Ga-DOTATATE 68 XR (spine); CT; XR (spine); CT; Imaging NA EUS; MRI CT; MRI; fexible MRI; fexible CT; MRI; U/S US; MRI CT; MRI CT; EUS; MRI XR pelvis; CT; CT; XR pelvis; CT; CT; Barium enema; CT; MRI; PET CT; None Family history Family NA NA NA None NA Prostate Ca Prostate NA NA NA NA None NA essential throm - bocythaemia; Ca; stapled renal haemorrhoidec - tomy uterine fbromas of at 45 years slipped age; lumbar disc malformation malformation on) (operated None Past medical Past history NA ? Anal fstula Ulcerative colitis; Ulcerative Hysterectomy for for Hysterectomy None Congenital renal renal Congenital Nil None Birth twins to NA None NA gait difculties, gait recurrent urinary infections, tract dysfunction bowel puration (2 months)puration pelvic pain (3 years) pelvic pain; peri-umbilical mass urinary retention (3 years) months) coccydynia, urinary fall; post frequency pain worsening during evacuation tal pain, increased urgency defecation (3 weeks) impaired defecation defecation impaired perianal and urge, sensorygluteal dis - turbance (1 year) Worsening back pain, back Worsening Presenting symptoms Presenting NA Anal discomfort, sup - Anal discomfort, Worsening back and back Worsening Increased lumbar Increased Acute presentation— Acute Low back pain back Low Constipation (few (few Constipation Acute presentation— Acute Persistent rectal pain Persistent - pain, rec back Lower Left pain, gluteal NA F Sex F F F F M M M F F M M F 28 24 56 73 63 35 53 49 25 41 61 53 39 Age 2011 2013 2017 2010 2011 2014 2018 2014 2018 2014 2015 2017 Years (continued) et al. [ 36 ] et al. et al. [ 31 ] et al. [ 37 ] [ 34 ] 1 Table References Niazi et al. [ 29 ] Niazi et al. Mora-Guzmán Mora-Guzmán Damato et al. [ 30 ] et al. Damato Stefano et al. [ 27 ] et al. Stefano Charalampakis Charalampakis Al Khaldi et al. Al Khaldi et al. Spada et al. [ 28 ] Spada et al. Kim et al. [ 32 ] Kim et al. Iwata et al. [ 8 ] et al. Iwata Abukar et al. [ 33 ] et al. Abukar Mitsuyama et al. et al. Mitsuyama Acar et al. [ 35 ] et al. Acar

1 3 Clinical Journal of Gastroenterology (2019) 12:539–551 543 tailgut cyst and tailgut cyst metastases); liver cholecystectomy position of due to metastases liver surgically explored explored surgically and biopsies (with - out resection). The patient then underwent two of induction cycles chemotherapy (cisplatin, VP-16, with ifosfamide) no efect; an addi - tional three cycles dac - of adriamyin, arbazine, cytoxan also had no efect. The patient then underwent surgical excision Surgical resection Surgical Yes (resection (resection Yes Yes Other notes Lesion was initially initially Lesion was Further man - agement Nil NA NA Pre-operative Pre-operative biopsy Yes No Post-operative Post-operative metastases No No No Tumour markers Tumour Normal Normal - Recur rence No No No Pre-operative Pre-operative metastases Yes—liver No Follow-up Follow-up term 24 months 48 months 36 months Sacral or coc - Sacral cyx invasion No No Immediate post-operative management Surveillance Nil Nil Ki-67 of tailgut cyst NET NA NA NA DOTATATE DOTATATE PET/CT Imaging CT; MRI; Ga68 CT; U/S; CT; MRI U/S; CT; - NET grade NA NA NA multiforme multiforme (son), prostate lung Ca (father), Ca (maternal aunt), ovarian Ca (maternal grandmother), colon Ca (mater nal grandfather) Family history Family Glioblastoma Glioblastoma None Clear margins - on resec tion NA NA NA - cinoma, prostate cinoma, prostate Ca, melanoma Past medical Past history Squamous cell car Squamous None - of symp Time resection to toms NA NA > 1 year - (amputated sacrum, infltrating lobular tumour mass, attached loop, adher bowel mus - ent skeletal cle, soft tissue) to knee to dysmenorrhoea Size of resected Size of resected specimen 18 × 14 6 cm NA NA Presenting symptoms Presenting Left hip pain radiating Abdominal pain, Abdominal - Sex M F 77 33 Age neal and posterior en - bloc resec tion of mass to (adherent and rectum thus requir ing abdomi - noperineal resection); of resection S2-24 lesion lesion Operation - Transperito Resection of Resection Resection of Resection 2018 2018 Years 1994 1998 Years (continued) [ 19 ] et al. [ 20 ] et al. 1 Table References References Schnee et al. et al. Schnee Erdrich et al. [ 38 ] Erdrich et al. Horenstein Horenstein Present case Present

1 3 544 Clinical Journal of Gastroenterology (2019) 12:539–551 - 12 months post with similar morphology the to tumour; presacral at 13 months post, recur CT showed of presacral rence tumour diarrhoea- symp resolved, toms numbness however and pain extending the left leg down continued Breast lumps noted noted lumps Breast Other notes At time of follow-up, time of follow-up, At sis (detected sis (detected post- 1-year operatively): - chemo withtherapy - 5 ′ -fuoroura cil. 3 months - chemo post therapy, developed diplo - pia—brain metastasis detected— palliative radiation NA Further man - agement NA NA Nil NA Liver metasta - Liver Breast Post-operative Post-operative metastases No NA No NA Liver, brain Liver, - Yes Recur rence No NA No NA No 13 months Follow-up Follow-up term 24 months 6 months 12 months NA > 15 months Nil Immediate post-operative management NA Surveillance Surveillance NA Surveillance NA Ki-67 of tailgut cyst NET NA NA NA NA NA NA NET grade NA NA NA NA NA second - proce dure required NA Clear margins - on resec tion Unclear— NA Yes NA NA tion NA - of symp Time resection to toms > 1 year > 3 years > 3 years NA Acute presenta - Acute within a 2 × 2 cm piece of fbrous tissue with S5 attached NA Size of resected Size of resected specimen 1.5 cm (NET) NA 1.2 cm frm nodule NA NA lesion lesion approach, approach, of resection retrorectal lesion and excision of S5 operineal resection Resection of Resection Operation Resection of Resection NA Posterior Posterior NA - Abdomin 2000 2000 2003 2004 2004 Years (continued) [ 7 ] [ 12 ] [ 21 ] [ 22 ] [ 23 ] References 1 Table Prasad et al. et al. Prasad Oyama et al. et al. Oyama Mourra et al. Jacob et al. Jacob et al. Song et al. Song et al.

1 3 Clinical Journal of Gastroenterology (2019) 12:539–551 545 biopsy was treated treated biopsy was with long-acting somatostatin ana - logue. Represented 15 months post initial presentation with deterioration in clinical condi - tion and difuse pain. Increased node size and chromogranin Treated A level. with somatostatin analogue but then declined treatment after 3 months Other notes Not operated. Post Post operated. Not radionuclide radionuclide therapy; hysterectomy, bilateral adnexectomy; long-acting somatostatin analogue therapy Further man - agement – NA NA Nil Nil Peptide receptor receptor Peptide Nil Nil multiple bone metastases, nodes Post-operative Post-operative metastases – No NA No No Left adnexa, Left adnexa, No No - Recur rence – No NA No No Yes No No Follow-up Follow-up term – 24 months NA 5 months 25 months 79 months 12 months 3 months (carboplatin, etoposide) surveillance Immediate post-operative management – NA NA Surveillance Surveillance Chemotherapy Chemotherapy Physiotherapy, Physiotherapy, Surveillance 2.9% 18% Ki-67 of tailgut cyst NET NA < 1% < 2% < 2% Low grade Low NA 1 1 1 1 2 1 NET grade NA NA Clear margins - on resec tion – Yes Yes NA Yes NA NA NA - of symp Time resection to toms > 2 years NA > 3 years > 42 months NA > 1 month NA NA diameter 2.5 cm diameter containing 3 mm tumour carcinoid (soft tissue + 20% space) cystic (mass) (cystic/solid mass); (cystic/solid 1.5 cm (NET) Size of resected Size of resected specimen Not resected Not Cystic lesion with Cystic 4.6 × 4.1 3.9 cm 3.7 × 3 2.5 cm 5.8 × 3.5 4.3 cm NA NA NA lesion for resection resection for of mass resection resection of presacral mass adnexectomy approach approach with intersphinc - teric and - para-sacro coccygeal excisions nectomy and nectomy duraplasty; repair dural patch Operation – Resection of Resection Laparotomy Laparotomy Laparoscopic Laparoscopic Bilateral Bilateral Posterior Posterior T10-S4 lami - Radical excision Radical 2005 2005 2008 2010 2011 2011 2013 Years (continued) [ 24 ] [ 25 ] [ 26 ] [ 27 ] [ 28 ] [ 29 ] References 1 Table Luong et al. et al. Luong Mathieu et al. Mathieu et al. Liang et al. Liang et al. Stefano et al. et al. Stefano Spada et al. Spada et al. Niazi et al. Niazi et al. Damato et al. [ 30 ] et al. Damato

1 3 546 Clinical Journal of Gastroenterology (2019) 12:539–551 surgery, a residual a residual surgery, mass in the rectum and noted was withmonitored serial imaging as the patient refused additional surgery (unclear if NET or progres- No not). otherwise sion was in the noted 2-year period follow-up Other notes One month after analogue; - chemo therapy, due to PPRT progressive disease Further man - agement Nil NA NA NA NA Somatostatin orbital, cardiac, skin, subcu - taneous (left groin), lungs, liver Post-operative Post-operative metastases No NA NA Lymph nodes Lymph Breast, retro- Breast, No Lymph nodes Lymph - Recur rence No See note NA No NA No No Follow-up Follow-up term 36 months 24 months NA 28 months 48 months 7 months > 24 months by blad - by der + bowel dysfunction, CSF leak; re-operation completed and started somatostatin analogue treatment Immediate post-operative management Surveillance NA NA Complicated Complicated Chemotherapy NA Surveillance 4% 12.5% Ki-67 of tailgut cyst NET Low grade Low Low grade Low 2–5% < 2% 5–10% 1 2 1 2 1 NET grade NA 2–3 Clear margins - on resec tion NA NA No NA NA NA Yes tion - of symp Time resection to toms Acute presenta- Acute NA > 3 weeks > 1 year NA > 2 months > 6 months–3 years (collapsed cyst) (collapsed cyst) with maximal wall 6 mm thick (tumour mass) lesion) (specimen), coccyx 3.7 × 1.0 2.7 cm Size of resected Size of resected specimen 10 × 8.5 1.1 cm NA 5.9 × 4.2 2.7 cm NA NA 4.5 × 2.5 cm (solid 7.6 × 3.9 2.5 cm sion operineal resection sacral lami - sacral nectomy approach; approach; partial coc - cygectomy tomy; en tomy; - bloc poste rior surgical of resection mass Operation Laparotomy - exci Transanal - Abdomin Osteoplastic Osteoplastic NA Posterior Posterior - Coccygec 2014 2014 2014 2015 2017 2017 2018 Years (continued) et al. [ 31 ] et al. [ 33 ] et al. [ 34 ] et al. et al. [ 36 ] et al. et al. [ 37 ] et al. References 1 Table Charalampakis Charalampakis Kim et al. [ 32 ] Kim et al. Abukar et al. et al. Abukar Mitsuyama Mitsuyama Acar et al. [ 35 ] et al. Acar Mora-Guzmán Mora-Guzmán Al Khaldi

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of the lesion abutted the sacrum and coccyx; there was no communication with the central spinal canal. The cyst displaced the uterus anteriorly, displaced, and compressed the bladder anteriorly, and compressed the rectum at the

taken at time of taken - resec tailgut cyst tion had Ki-67 of 6.4% (grade 2 NET) left anterolateral margin of the cyst without evidence of Other notes Liver metastases Liver fne-needle - aspira upstream bowel dilatation.

FNA Given her ongoing and worsening symptoms, the patient subsequently opted for surgical resection. A midline laparotomy was performed considering the size of the lesion. Further man - agement NA NA Nil There were omental adhesions to the large cyst and careful

- imaging, U/S ultra resonance magnetic dissection performed to gain access to the pelvis. Due to its size, we decompressed the cyst through a small trephine, MRI Post-operative Post-operative metastases NA NA No suctioned the clear fuid content, and closed the defect with 3–0 PDS to control any leakage. The mass itself was easily - separated from the rectum and pelvic sidewalls. Due to the Recur rence No NA No size of the dissection bed, a Jackson-Pratt drain placed left to the posterior rectum and into the pelvis. On digital rectal examination, there was a right posterolateral fstula opening in the anal sphincter, but no tracts noted. No intervention Follow-up Follow-up term NA NA 7 months computed CT computed tomography, was performed on this at the time of operation. Macroscopically, the collapsed cyst structure was 12.8 × 8.5 × 2.1 cm in size, was multiloculated with a wall

cancer, Ca cancer, thickness ranging from 2 to 15 mm, and had both solid and Immediate post-operative management NA NA Surveillance cystic components. Histologically, the cyst was surrounded by fbrofatty tissue and skeletal muscle. It was mostly lined by non-neoplastic squamous epithelium showing surface 8% 8.6% not not available, Ki-67 of tailgut cyst NET 1–2% keratosis and hyperplasia and had focal lining of some fuorodeoxyglucose, fuorodeoxyglucose, 18F-FDG nuclear medicine metaiodobenzylguanidine,

NA locules by cytologically bland-ciliated cuboidal cells with scant goblet cells (Fig. 2a). There was one focus within the 2 2 1 adjacent fbrous wall, which showed an infltrative neo- female, F female, NET grade plasm (Fig. 2b, c). This was described as solid nests, “rib- bon like” cords as well as some tubular structures of mildly

M male, pleomorphic cuboidal to columnar cells. Focally, the cells Clear margins - on resec tion NA NA Yes had more abundant eosinophilic cytoplasm. There were less than 1 mitoses per 10 high-power felds. There was no necrosis. The lesional cells surrounded a nerve fbre, but

not not available, did not appear to show perineural invasion. The focus of - of symp Time resection to toms > 8 months NA > 8 years NA tumour was approximately 1.0 × 1.5 cm (microscopically)

positron emission tomography, NM MIBG emission tomography, positron with no lymphovascular space invasion. The neoplastic cells had difuse strong staining with cytokeratin AE1/3 (Fig. 2d) PET and neuroendocrine markers’ chromogranin (Fig. 2e) and synaptophysin (Fig. 2f). There was difuse weak staining (specimen) 2.1 cm (cystic 2.1 cm (cystic structure); 1.0 × 1.5 (NET) Size of resected Size of resected specimen 6.7 × 2.0 1.8 cm NA 12.8 × 8.5 up to with CDX2 and ER. There was patchy (< 10%) staining with CK7 and the cells were negative with CK20. The Ki-67 pro-

cerebrospinal CSF cerebrospinal fuid, liferating index was noted to be 1–2%. The neoplasm was described as a well-diferentiated NET arising in the vicinity approach Operation Posterior Posterior Laparotomy Laparotomy of a benign cyst. The NET was approximately 2 mm clear of

EUS endoscopic ultrasound, the apparent surgical resection margins. 2018 2018 2018

Years Tumour marker values were unremarkable. Pre-operative staging CT scans did not locate any evidence of malignancy (continued)

X-ray, XR X-ray, throughout the entire time period. Gastroscopy and colonoscopy were unable to identify a mucosal source for the NET. [ 38 ] References 1 Table NET neuroendocrine tumour, sound, Iwata et al. [ 8 ] et al. Iwata tion Erdrich et al. Erdrich et al. Present case Present Given these fndings and with the resected sample clear of

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Fig. 1 Magnetic resonance imaging obtained 3 months prior to opera- image of the mass showed a T1 hyperintense mildly lobulated focus tive resection measured a persistent and septated cystic mass in the anteroinferiorly measuring 1.8 × 1.1 cm, demonstrating fat saturation. pelvis as 11 × 11 × 12.6 cm. a T2-weighted sagittal image of the mass c Axial T2 fat saturated image shows the fat focus in the area, where shows the posterior margin of the lesion abutting the sacrum and coc- it was seen previously on CT imaging from 3 years prior to operative cyx with acute angulation of the sacrococcygeal junction. b Coronal resection neoplastic cells in its margins, the patient was surveyed with difcult to estimate the true incidence of tailgut cysts hav- interval CT scan. ing malignant transformation, with the literature containing mostly single-case reports and small-case series that include patients with NET. Most NET occurring in the presacral Discussion space are associated with local extension of a primary rectal carcinoid or metastasis from an alternative source [13]. A tailgut cyst is an example of a retrorectal tumour that Thus, primary NET of the presacral space is rare. forms in the presacral space and is derived from the incom- A few retrospective reviews have attempted to review plete regression of the embryonic hindgut [2, 11, 12]. Over- the incidence of malignant change in tailgut cysts overall. all, tailgut cysts have been reported as more common in Mathis et al. [3] reported 31 patients (28 women) with tail- females, with a mean age of presentation in the 5th dec- gut cysts over a 23-year period and across three institutions. ade [1, 2]. Tailgut cysts may undergo malignant change All patients underwent surgical resection, and four of them including adenocarcinoma, sarcoma, and NET [3–6]. It is (13%) had developed malignant change: adenocarcinoma

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Fig. 2 Histology of the resected tailgut cyst. a Cyst lining with squa- A1/3, e Tumour cells showing positive chromogranin and f synapto- mous and glandular areas. b, c Section of cyst with adjacent neu- physin stains showing neuroendocrine diferentiation roendocrine tumour. d Tumour cells strongly positive for Cytokeratin in three and NET in one. Two of the four patients with However, the incidence of non-diagnosed asymptomatic malignant cysts had died in the follow-up period. Rates of cysts in the general population is unknown, and thus, it malignant degeneration have also been reported at 6% [5], would be impossible to accurately estimate the risk of future 9% [15], and 21% [6] in other studies. On the other hand, malignancy from a tailgut cyst. the largest series in the literature from Hjermstad et al. [2] Pre-operative diagnosis of NET in a tailgut cyst can be reported 51 patients with tailgut cysts and only 1 of them challenging. Pre-operative biopsy was utilised in some, (2%) was accompanied with adenocarcinoma. Given that but not all studies, to confrm the presence of NET; these the range of malignant degeneration has been reported from cystic lesions must be carefully sampled, as they can be 2 to 21%, studies have concluded that tailgut cysts should quite large, and a malignant neoplasm may be some dis- be removed because of the risk of malignant transforma- tance from the benign portion of the lesion [12]. Imaging tion, even if the patient is asymptomatic from the cyst [3]. is important for pre-operative diagnosis of tailgut cysts

1 3 550 Clinical Journal of Gastroenterology (2019) 12:539–551 to determine an optimal surgical approach and extent of Human rights All procedures followed have been performed in accord- resection [10, 16]. CT scan has been the most common ance with the ethical standards laid downin the 1964 Declaration of Helsinki and its later amendments. frst-line imaging modality in our review. CT can be used to demonstrate a well-circumscribed, presacral cyst con- Informed consent Informed consent was obtained from all patients for taining water, or soft-tissue density and calcifcations. In being included in the study. cases of malignant transformation, CT can reveal a loss of defned cyst margins as well as involvement of neighbour- ing structures [16]. In comparison, MRI scanning ofers References clearer visualisation of the multilocular appearance of the tailgut cyst together with improved detection of smaller 1. Devine RM. Managing presacral tumours. 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