A 44-year-old female patient was subjected to total colonoscopy that revealed a 15 mm bulge in the cecum, covered by normal mucosa, compatible with subepithelial lesion, of hard consistency and no pillow sign (Fig. 1a). The lesion was evaluated by ultrasonography with mini-probe (Fig. 1b), which confirmed the presence of a sub-epithelial nodular hypoechoic lesion although it was not possible to safely distinguish between the second and third ultrasonographic wall layers.
![](/img/revistas/ges/v30n6//2341-4545-ges-30-06-59-gf1.png)
Fig. 1. Endoscopic findings. a In the cecum, a 15 mm bulge with normal mucosa was observed. b Ultrasonography - a subepithelial nodular lesion was confirmed, although it was not possible to safely distinguish between the second and third ultrasonographic wall layers.
Endoscopic submucosal dissection (ESD) was pro-posed. The endoscopist had extensive experience in colorectal ESD. A glycerol solution with indigo carmine and adrenaline (1:50,000) was injected (Fig. 2a). Mucosal incision was performed (Fig. 2b), followed by submucosal endoscopic dissection using DualKnife JTM (Olympus, Tokyo, Japan) and IT Knife nanoTM (Olympus, Tokyo, Japan), with dry-cut current effect 2.5 and swift coagulation current effect 3 achieving total excision of the lesion at the end of the procedure (Fig. 2c-e). The scar was closed with Resolution 360TM ULTRA clips (Boston Scientific, Boston, USA) (Fig. 2f, g). The lesion was retrieved en bloc (Fig. 2h). No adverse events were observed.
![](/img/revistas/ges/v30n6//2341-4545-ges-30-06-59-gf2.png)
Fig. 2. Endoscopic submucosal dissection. a Submucosal injection. b Mucosal incision. c-e Submucosal dissection. f Dissection scar. g The scar was closed with clips. h En bloc lesion retrieval.
Histological evaluation revealed a solid neoplasia of the submucosa consisting of epithelioid cells of vast granular citoplasma, centered by small, round, uniform nuclei (Fig. 3a, b). These cells were positive for S100 and inhibin - granular cell tumor (GCT) (Fig. 3c, d). The lesion was limited to the submucosa and was covered by normal colonic mucosa. The excision margins were free. A surveillance colonoscopy at 12 months is currently scheduled.
![](/img/revistas/ges/v30n6//2341-4545-ges-30-06-59-gf3.png)
Fig. 3 Histological evaluation. a Submucosal expansion by epithelioid cells, covered by normal colonic mucosa (×20 magnification). b These cells have vast granular citoplasma, centered by small, round, uniform nuclei (×100 magnification). c, d Immunohistochemistry showing positivity for S100 (c) and inhibin (d) (×400 magnification).
The authors present a case of a subepithelial lesion in the cecum evaluated by miniprobe ultrasonography and removed en bloc by ESD. GCT’s are a rare entity, whose pathological behavior is not fully understood, and are most frequently found incidentally. Granular cells have neuronal origin, and Schwann cells are precursors [1, 2].
The cases reported in the literature suggest a generally benign behavior but <2% have shown potential for malignancy, which is suggested by endoscopic features of ulceration or size >40 mm [3]. Histological proposed criteria for malignancy are the following: high number of mitosis, big nuclei, signs of lymphovascular invasion; evidence of metastization being the sole definitive criteria [2]. A case of local recurrence due to incomplete resection was reported [3]. ESD in the colon is a safe, technically demanding procedure that allows an en bloc resection and avoids surgery in the absence of features of malignancy. Endoscopic fullthickness resection using a full-thickness resection device is an alternative and developing method, with current evidence apparently showing a similar safety profile albeit with a lower complete resection rate [4]. To the best of our knowledge, this is the first case of GCT in the cecum treated by ESD in the West; all the other four cases were reported in China [5, 6].