A large cystic gastrointestinal stromal tumor of the rectum in the retrorectal space

Abstract

A 54-year-old man presented with pain on defecation and rectal bleeding. Colonoscopy revealed a submucosal tumor extending from the lower rectum to the upper rim of the anal canal, which compressed the rectal wall inward by two thirds of its circumference. Magnetic resonance images demonstrated a 70 × 80-mm unilocular cystic mass with a solid portion in the periphery in the retrorectal space, which displaced the rectum anterolaterally. The peripheral solid portion was hypointense on T2-weighted images and not hyperintense on diffusion-weighted images, suggesting low cellularity of the lesion. Cytological examination of the clear and serous fluid obtained by transrectal biopsy showed the presence of normal columnar and squamous epithelial cells and the absence of malignant cells. Therefore, the cystic retrorectal mass was presumed to be tailgut cysts rather than gastrointestinal stromal tumors (GISTs). The mass and rectum were extirpated en bloc with an adequate surgical margin by laparoscopic intersphincteric resection. Pathologically, spindle tumor cells proliferated with nuclear palisading and were strongly immunopositive for c-kit, leading to a final diagnosis of rectal GIST. There are no reports describing a huge, cystic rectal GIST arising in the retrorectal space, which should be considered in the differential diagnosis of cystic retrorectal lesions.

Management approach and surgical strategies for retrorectal tumours: a systematic review

“…Both neoadjuvant and adjuvant therapy for GIST with imatinib has been shown to reduce the risk of recurrence, as even after a macroscopically complete resection with negative margins there is a significant recurrence risk without imatinib. There are reports of variable radiological appearance of GIST which can be distinguished on biopsy .…”

Tailgut Cysts with Malignant Transformation: Features, Diagnosis, and Treatment

“…However, based on the pathological examination, spindle tumor cells had multiplied in the nuclear palisade, and c-kit was positive. The ultimate diagnosis was rectal gastrointestinal stromal tumors (GISTs) [44].…”

Gastrointestinal stromal tumors (GISTs) with remarkable cystic change: a specific subtype of GISTs with relatively indolent behaviors and favorable prognoses

“…Small cystic areas are frequently observed in GISTs with large size, but GISTs rarely manifest predominantly as cystic tumors. Cases of this uncommon form have been described but no retrospective study has been reported in the English literature (Hamza et al 2016 ; Okano et al 2015 ; Shaikh et al 2015 ; Sun et al 2016 ; Takahashi et al 2010 ; Wang et al 2017 ; Zhu et al 2014 ). In addition, clinical follow-up information was not available in most cases.…”

“…GISTs are typically solid, sometimes with small cystic area developed, but rarely manifest as predominant cystic neoplasms. To date, reports of this uncommon form of GISTs have comprised mostly case reports focusing mainly on its clinical and radiographic features (Hamza et al 2016 ; Okano et al 2015 ; Shaikh et al 2015 ; Sun et al 2016 ; Takahashi et al 2010 ; Wang et al 2017 ; Zhu et al 2014 ). There is very limited information in the literature relating to the pathologic features and prognoses of GISTs undergoing extensive cystic change.…”