Fine Needle Aspiration Cytology Diagnosis of Tailgut Cyst: A Rare Entity

Abstract

Background: Tailgut cyst is a rare tumor believed to originate from small portions of the embryonic tailgut, which normally disappear in early fetal development. It is often misdiagnosed due to the general unfamiliarity with this entity and also because of its clinical presentation similar to other more common diseases such as perianal fistulas and abscesses. Case: The authors take this opportunity to report a case of tailgut cyst in a 21-year-old Saudi female. The patient had presented with painful low back swelling, which had been gradually increasing in size. The case was diagnosed by fine needle aspiration cytology (FNAC) as tailgut cyst and later confirmed by histopathology. Conclusion: Tailgut cysts are congenital cystic hamartomatous lesions, which are rare in occurrence. They are generally benign, but malignancy has also been reported, which is even rarer in occurrence. FNAC is an effective diagnostic tool, which if applied appropriately can be used for the early detection of rarer lesions such as tailgut cyst.

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

“…The eligible papers and Table give a good impression of the typical case. The relative risk for malignant transformation was raised in the case of finding nodular thickening of the cyst wall on radiology ( P = 0.0023).…”

Tail gut cyst adenocarcinoma: A rare entity diagnosed on cytology

“…However, sometimes tailgut remnants in the retro rectal space persists giving rise to tail gut cyst. 1 Congenital lesions are by far the most common tumor type in this region, accounting for 55-70% of all presacral tumors. These tumors are present from birth because of the growth of embryological remnants, and they include cystic (developmental cysts, rectal duplication cysts, and anterior meningoceles) and solid (chordomas, teratomas, and adrenal rest tumors) lesions.…”

“…Based on morphology, developmental cysts are classified into dermoid cysts, epidermoid cysts, tailgut cysts (TGCs) and cystic teratomas. 1,2 Primary adenocarcinomas of the retro rectal or presacral space are uncommon and usually arise from the remnants of the embryological postnatal gut which contain mucous secreting epithelium. Clinical diagnosis is usually delayed due to non-specific symptoms and histological diagnosis can be obtained only after a biopsy or surgery.…”

Imaging of tailgut cysts

“…Associated inflammation is frequently present. From all reported cases between 1932 and 2011, 14% of patients with tailgut cysts were malignant, with subtypes including adenocarcinoma, neuroendocrine, squamous cell, sarcoma, and endometrioid adenocarcinoma [3,6].…”

“…In one series, patients underwent an average of 5 invasive procedures prior to being correctly diagnosed [7]. A tailgut cyst may be mistaken for a perianal fistula or abscess [6]. On physical examination, tailgut cysts are usually palpable, with digital rectal examination revealing an extrinsic cystic, fluctuant mass [5].…”