S4384 Esophageal Nerve Sheath Tumor: A Rare Benign Tumor With Diagnostic Challenges

Introduction: Esophageal nerve sheath tumors are an uncommon type of esophageal submucosal tumors, with fewer than 30 cases reported in the literature. They arise from Schwann cells of the peripheral nervous system and are histologically defined by spindle-shaped cells with strong S-100 positivity and a lack of CD117, CD34, smooth muscle actin, and desmin. These tumors typically occur as a solitary lesion in individuals aged 40–70, with a slight female predominance and possible links to genetic syndromes such as Neurofibromatosis Type 2. Due to their rarity, they are often poorly recognized clinically and misdiagnosed before surgery. We present a rare case of esophageal nerve sheath tumor to add to the limited existing data and support a better understanding of this entity. Case Description/Methods: A 46-year-old man underwent an upper endoscopy and colonoscopy for work up for iron deficiency anemia. The endoscopy revealed a polypoid submucosal lesion in the esophagus (Paris class Isp) at 37 cm from the incisors. Subsequent endoscopic ultrasound revealed a hypoechoic, well-demarcated lesion within the submucosa, measuring 9 mm × 7 mm × 5 mm and 4.6 mm in thickness. The biopsy showed reactive squamous mucosa and subepithelial spindle cell proliferation. Due to concern for malignant potential endoscopic submucosal dissection was performed with complete resection with no complications. Histopathology revealed well-formed subepithelial nodule consisting of localized spindle cell proliferation, Schwann cells, a mixed population of inflammatory cells, and multiple ectatic vessels throughout the lesion. Immunohistochemical analysis was positive for S100, SOX10, Bcl2, along with CD68, CD163, and CD117, indicating a prominent mast cell population and scattered histiocytes. The overall features are suggestive of a benign nerve sheath lesion, with subtypes of neurofibroma and mucosal Schwann cell hamartoma among the differentials. Discussion: This case highlights the importance of including benign nerve sheath lesions in the differential diagnosis of submucosal esophageal masses. Their morphological complexity contributes to diagnostic difficulties and has led to a variety of terms being used historically to describe similar lesions. Submucosal esophageal lesions, while uncommon, can be effectively managed with minimally invasive techniques when identified promptly.