Esophageal granular cell tumor successfully resected by endoscopic submucosal dissection
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Granular cell tumors of the esophagus are rare neoplasms and their diagnosis is mainly based on histopathologic examination of endoscopic biopsies. With the development of endoscopic techniques, there has been a marked increase in local treatment modalities for early esophageal neoplasms. In this case report, we describe the removal of a granular cell tumor by the endoscopic submucosal dissection technique, and briefly discuss the literature on clinicopathologic aspects and management of granular cell tumors.
KeywordsBiopsy Esophageal neoplasms Granular cell tumor Surgical endoscopy
Granular cell tumors (GCT) are relatively infrequent lesions that were initially described by Abrikossoff  as part of a series of 5 tumors of the tongue, which he termed myoblastoma. In 1931, he described the first case of this kind of neoplasm located in the esophagus  and since then approximately 200 cases of GCT have been documented .
In the esophagus, the lesion is generally restricted to the submucosal layer, although occasionally it can also affect the mucosal layers and muscularis propria of the organ. Histologically, different cell types, for example histiocytes, fibroblasts, or intestinal mesenchymal cells, have been reported to be the source of this tumor. However, the most widely accepted theory was that it was of myogenic origin, hence its former name of “granular cell myoblastoma”. Since 1950 and with the introduction of histochemical techniques, it has clearly been shown that it is of neurogenic origin, arising from the Schwann cells  which, in the esophagus, form part of the submucosal neuronal plexus. There are many cases of endoscopic mucosal resection (EMR) as treatment for GCTs. However, to our knowledge, there are few reports of endoscopic submucosal dissection (ESD) . This article reports a case of a GCT in the esophagus which was resected by ESD.
Although GCTs are uncommon tumors in the GI tract, nearly one-third occur in the esophagus [6, 7], the most common site of origin of GI GCTs. Most esophageal GCTs are found incidentally during endoscopy of the upper GI performed for other reasons. Although a GCT is usually asymptomatic, when the tumor is larger than 1 cm, it may cause dysphagia .
A GCT has a characteristic appearance on endoscopy. The tumor usually appears as a yellowish-white, firm, sessile submucosal mass. Differential diagnosis should include an esophageal cyst, epithelial lesions, for example glycogenic acanthosis, an inflammatory polyp, squamous papilloma, and other submucosal tumors, for example leiomyoma, lipoma, and hamartoma .
GCTs were originally considered to be of myogenic origin, but electron microscopic and immunohistochemical studies confirmed the Schwann-cell origin of the tumors. Histologically, these tumors consist of polygonal and fusiform cells in compact “nests” . Cells have small dark nuclei and abundant, fine, granular eosinophilic acid-Schiff-positive, diastase-resistant cytoplasm . GCTs of the skin, larynx, and esophagus are known to induce pseudoepitheliomatous hyperplasia in the malpighian epithelium. This feature may simulate a primary squamous cell carcinoma [7, 10].
Although the natural history of the tumor is unclear, most esophageal GCTs have a benign clinical course. However, approximately 1.5–2.7% of all cases reported in the literature were regarded as malignant variants. The infiltrative growth pattern and the presence of metastases are important features in differentiating between malignant and benign tumors because they may be of very similar appearance histologically. Malignant lesions are usually larger than 4 cm, with evidence of rapid recent growth, tend to recur locally after resection, and may have subtle histologic features, for example nuclear pleomorphism, increased nuclear size, tumor cell necrosis, large nucleoli, mitotic figures (2 or more/10 high power fields), and tumor cell spindling .
The optimum treatment for GCTs remains controversial, but the current treatment options are a conservative approach with regular endoscopic follow-up for tumors <10 mm in diameter without evidence of malignant change , and surgical excision for tumors >20 mm in diameter, benign GCTs causing symptoms, or when malignancy is suspected . If no malignant changes are detected in the removed specimen, additional treatment or follow-up is not considered necessary . EMR was recently reported to be an effective treatment, and EUS is thought to be most useful for deciding if a tumor meets the criteria for endoscopic removal, including small size (<20 mm) and non-attachment to the muscle layer [14, 15]. In a series of 650 esophageal mucosal cancers removed with EMR, Makuuchi  reported an incidence of complications of 4.8% (perforation 0.7%, bleeding 3.1%, stricture 1.6%).
ESD for esophageal pathology has recently been established, and the affected mucosa is incised and removed using a variety of endoscopic electrosurgical knives. Using ESD, a wider range of the mucosa can be resected in one piece more reliably using an endoscope. Takahashi et al.  reported that the incidence of complications was not significantly different between ESD and EMR—perforation 2.6%, mediastinal emphysema 4.3%, pneumonia 2.6%, and stenosis 17.2%. In our case, after submucosal injection of sodium hyaluronate to maintain sufficient thickening of the submucosal tissue, dissection of the mucosa and submucosa with a Flush knife was performed by the method developed by Toyonaga . We preferred ESD for its more accurate resection than conventional EMR, and sodium hyaluronate solution for its ability to maintain submucosal elevation for a longer time . Additional esophagectomy with lymph node dissection was not required, because no submucosal invasion or vessel permeation was seen in the endoscopically resected specimen.
Endoscopic resection is less invasive and, for smaller tumors, results in fewer complications than esophagectomy; on the other hand there is a case report of EMR of a malignant GCT with a diameter of 10 mm . With regard to GCTs from 10 to 20 mm in diameter, we believe endoscopic resection (EMR or ESD) may be preferable, as described elsewhere [19, 20].
Concerning esophageal GCTs exceeding 20 mm, esophagectomy had been performed until quite recently. However, esophagectomy is the therapeutic option with the highest mortality . Because ESD has been established as safer and less invasive therapy, it is expected to be the best therapeutic option for mucosal or submucosal esophageal GCTs exceeding 20 mm.
In summary, GCTs of the esophagus are rare neoplasms. Endoscopic biopsies are the mainstay of diagnosis. Endoscopic and endosonographic evaluation of the lesion defines the location and extent of the tumor and its suitability for endoscopic treatment. ESD is a safe and accurate procedure for identified cases.
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- 1.Abrikossoff AI. Uber Myome, augehend von der quergestreiften willkurlichen Muskulatur. Virchows Arch Pathol Anat. 1926;260:214–33.Google Scholar
- 16.Makuuchi H. Endoscopic mucosal resection for mucosal cancer in the esophagus. Gastrointest Endosc Clin North Am. 2001;11:445–58.Google Scholar
- 17.Takahashi H, Arimura Y, Masao H, Okahara S, Tanuma T, Kodaira J, Kagaya H, Shimizu Y, Hokari K, Tsukagoshi H, Shinomura Y, Fujita M. Endoscopic submucosal dissection is superior to conventional endoscopic resection as a curative treatment for early squamous cell carcinoma of the esophagus (with video). Gastrointest Endosc. 2010;72:255–64, 264.e1–2.Google Scholar
- 19.Okahara S, Tanaka S, Haruma K. A case of granular cell tumor of the esophagus resected endoscopically. J Hiroshima Med Assoc. 1995;48:810–4.Google Scholar