Mucosal Schwann cell hamartoma of the gastroesophageal junction: A series of 6 cases and comparison with colorectal counterpart.

Mucosal Schwann cell hamartoma (MSCH) is an uncommon neural lesion characterized by an ill-defined proliferation of S100-positive Schwann cells in the lamina propria, with reported cases exclusively occurring in the colorectum. Here we describe the first series of MSCHs arising in the gastroesophageal junction (GEJ) and discuss their clinicopathologic features in comparison with their colorectal counterparts. We searched the UCLA pathology database from 01/2014 to 12/2018 to identify cases carrying the diagnosis of MSCH. A total of 48 cases (45 in-house, 3 consults) of colorectal MSCHs and 6 cases (1 in-house, 5 consults) of GEJ MSCHs were identified. For GEJ MSCHs, there were 4 males and 2 females with an average age of 70.2 years (range: 57-76 years). Clinical indications for endoscopy included history of gastroesophageal reflux disease (n = 2), heartburn (n = 2), dysphagia (n = 1), and iron deficiency anemia (n = 1). Endoscopic findings at the GEJ were available for 5 patients including irregular Z-line (n = 3), mild nodular carditis (n = 1), and normal (n = 1). None of them showed a polyp or nodule. The mean size of the lesion was 2.8 mm (range: 2-4 mm) microscopically. None of the colorectal or GEJ MSCH cases had an association with inherited syndromes. In conclusion, MSCH of the gastrointestinal tract is predominantly seen in the colorectum, but also infrequently seen in the GEJ. GEJ MSCH shares histologic and immunohistochemical features with its colorectal counterpart, but is usually an incidental finding with no endoscopically visible lesion. As there is no syndromic association with MSCH, additional treatment, work-up and follow-up are unnecessary.

Gastrointestinal stromal tumors: clinical profile, pathogenesis, treatment strategies and prognosis.

Abstract Gastrointestinal stromal tumors (GIST), although the most common mesenchymal neoplasms of the gastrointestinal (GI) tract, account for <1% of all GI malignancies. Up to 94% of these tumors express the CD117 antigen. Most patients present in the fifth to seventh decade, the commonest symptom being that of an abdominal mass. Surgery is the main modality of therapy, but even after adequate resection the vast majority of GIST reoccur, and in approximately 50% the liver is the main site of the metastasis. Long-term, maybe even lifelong follow up of these patients after initial resection cannot be over-emphasized. Initial tumor size and mitotic rate are the most useful parameters to predict malignant potential. In view of high postoperative recurrence, adjuvant forms of therapy are being explored, and the tyrosine kinase inhibitor imatinib holds the most promise.