Granular Cell Tumor of the Esophagus

Abstract

Purpose: 24 y.o. female referred for 10-month history of emesis and abdominal pain underwent EGD revealing a white-yellow submucosal growth at 32 cm from the incisors measuring 1 cm in length and 0.5 cm in width. Pathology report read: “One fragment consists of pink-staining granular cells with small, rounded nuclei consistent with granular cell tumor (GCT). Cells are strongly positive for S-100 and vimentin. Features of malignancy are absent”. Methods: Abrikossoff first described “granular cell myoblastoma” in 1926. It was considered a myogenic tumor until Fisher and Wechsler's 1962 challenge. Using electron microscopy and Wallerian degeneration studies, they noted similarities between a myoblastoma cell and a degenerating Schwann cell. Today, most pathologists and oncologists acknowledge the neural origin of GCTs supported by positive IHC staining for CD68, Ki-67 (slightly), NKI/C3, NSE, nestin, p53 (slightly), S-100 protein, and vimentin. In addition, positive PAS stain with resistance to diastase digestion and nonreactivity to HHF35, desmin, and alpha-smooth muscle actin are characteristic. Results: GCTs comprise only 0.03% of all tumors, and GI GCTs are even more rare with the distal 1/3 of esophagus cited most frequently. Mean age of diagnosis is 45 years with equal M:F ratio. Dysphagia is the most common symptom correlating to >1 cm size. Classic appearance is a small, non-tender, broad-based, submucosal growth resembling a “molar tooth” when central depression exists. A rubbery or firm consistency is characteristic with pinktan, gray-white, or white-yellow coloration. EUS reveals a homogenous, hypo/isoechoic submucosal lesion. Approximately 200 cases have been documented. Conclusion: GCTs are notoriously benign, but no management guidelines exist. Presently, an esophageal GCT > 2 cm size, symptomatology, interval growth, recurrence, tissue invasion, or advanced histologic/sonographic features prompt resection. Preoperative EGD re-evaluation with confirmatory biopsy followed by EUS to address muscularis and lymphatic invasion are recommended. EMR, Nd:YAG laser ablation, and APC are safe, effective alternatives to surgery in the absence of muscularis or lymphatic involvement. Esophageal GCTs are not radiosensitive, but recurrence is uncommon.Figure: Cells with granular, pink-staining cytoplasm and small nuclei.