P3128 - An Unexpected Gastric Invader from the Nervous System

Jeremy Feliciano-Ildefonso, MD, Zeyn Mirza, MD, José Martin-Ortiz, MD, FACG
VA Caribbean Healthcare System, San Juan, Puerto Rico

Introduction: Gastric schwannoma is a rare neoplasm of the stomach deriving from Schwann cells of the peripheral nerves accounting for approximately 0.2% of all gastric tumors. First described by Daimaru et al in 1988, these tumors are generally of benign nature with slow growth pattern, and asymptomatic, often found incidentally. However, due to difficulty differentiating from other submucosal tumors via non-invasive modalities, it is frequently misdiagnosed as an aggressive tumor such as Gastric stromal tumor (GIST). Thus, classification is of utmost importance to avoid unnecessary medical intervention. Hence, we present this case of a rare encounter with a gastric schwannoma that was found after an episode of acute gastroenteritis.

Case Description/Methods: Case of an 85 year old hispanic male who arrived at ER due to epigastric discomfort, with associated nausea and vomit of 3 days progression that began after eating fried chicken. Physical examination was remarkable for left upper quadrant tenderness to palpation. Laboratories were within normal limits. Abd/Pelvic CT with contrast demonstrated a large retrocaval node or soft tissue mass in the retroperitoneal area. In view of suspected malignancy, PET CT was performed revealing increased hypermetabolic uptake in the region with a size of 2.5 cm AP x 1.6 cm TR, with no further uptake observed elsewhere ruling out metastasis. Interventional radiology was consulted for CT-guided needle biopsy, which revealed peripheral nerve sheath tumor with scattered atypical spindle cells, some with nuclear pseudo-inclusions, and lipofuscin pigment deposition. Immunohistochemical staining was positive for S-100, SOX10, & CD34 with intralesional fibroblasts supporting classification of Schwannoma. Symptomatic treatment was provided with resolution of complaints; no surgical intervention was required given the benign nature of tumor and patient's resolution of symptoms.

Discussion: This case highlights the importance of taking a holistic approach to patient care especially patients of advanced age who may have findings suggestive of malignancy. Appropriate use of diagnostic techniques leads to an accurate diagnosis avoiding extraneous intervention and minimal harm to the patient. Misdiagnosis of this condition may lead to erroneous management and unwarranted interventions especially in patients of advanced age.


Disclosures:
Jeremy Feliciano-Ildefonso indicated no relevant financial relationships.
Zeyn Mirza indicated no relevant financial relationships.
José Martin-Ortiz indicated no relevant financial relationships.


Jeremy Feliciano-Ildefonso, MD, Zeyn Mirza, MD, José Martin-Ortiz, MD, FACG. P3128 - An Unexpected Gastric Invader from the Nervous System, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.