Synchronous mucosal Schwann-cell hamartomas in a young adult suggestive of mucosal Schwann-cell harmatomatosis: a case report

Schwann Cell Hamartoma Presenting as a Colonic Polyp: A Rare Case Report With a Literature Review

Mucosal Schwann cell hamartomas (MSCHs) are non-common noncancerous growths derived from Schwann cells in the peripheral nervous system, often found unexpectedly during routine colonoscopy examinations. These growths primarily occur in the colon, although they can also appear in the esophagus and are not linked to familial cancer syndromes. Diagnosis relies on specific histological characteristics and staining patterns. It is essential to distinguish MSCHs accurately since their appearance can closely resemble that of malignant tumors. Characteristically, these hamartomas test positive for S-100 protein but do not exhibit markers typical of other gastrointestinal growths, such as gastrointestinal stromal tumors (negative for KIT), leiomyomas (negative for smooth muscle actin), neurofibromas (negative for CD34), and perineuromas (negative for epithelial membrane antigen or claudin-1). This report discusses the case of a 48-year-old woman who was diagnosed with MSCH during a screening colonoscopy.

A Rare Case of Schwann Cell Hamartoma in the Duodenum

Mucosal Schwann cell hamartomas (MSCHs) are benign neural lesions that are not associated with inherited syndromes and are primarily found in the distal colon. We report the first case of an MSCH in the duodenum. This case highlights the expansive nature of MSCHs and discusses the implications of this finding in the duodenum and in the context of a hematologic malignancy.

Multiple non-polypoid mucosal Schwann cell hamartomas presenting as edematous and submucosal tumor-like lesions: a case report

Background

Mucosal Schwann cell hamartomas are rare neurogenic tumors which present most commonly in the distal colon. They are usually discovered as small, single polyps in asymptomatic patients.

Case presentation

An asymptomatic 64-year-old man was referred to us after a 12 mm subepithelial lesion was discovered incidentally on screening colonoscopy. Follow-up colonoscopy conducted 2 months later revealed that the tumor had disappeared, leaving multiple edematous, submucosal tumor-like elevations presenting as skip lesions throughout the sigmoid colon. Lesions had elongated pits on magnifying endoscopy and were limited to the first layer on endoscopic ultrasound. Biopsies revealed unclearly delineated foci of spindle-shaped cells limited to the lamina propria. On immunohistochemistry, all lesions were positive for S-100 protein and negative for CD34, CD56, and neurofilament protein. The patient was diagnosed with multiple mucosal Schwann cell hamartomas of the sigmoid colon. He remains asymptomatic after 18 months of follow-up, but the lesions have also remained unchanged.

Conclusion

We report a case of multiple non-polypoid mucosal Schwann cell hamartomas. Endoscopic findings may assist in the differential diagnosis, particularly when presenting as non-polypoid, submucosal tumor-like lesions.

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.

Mucosal Schwann Cell Hamartoma of the Rectosigmoid Junction: A Rare Lesion Mimicking Mucosal Prolapse Syndrome and Other Neural Lesions

In this article, we report the case of a 40-year-old woman with a sessile polyp of the rectosigmoid junction that underwent endoscopic resection. The resected specimen showed spindle cell proliferation with eosinophilic cytoplasm between mucosal crypts, mimicking mucosal prolapse syndrome. However, these were immunohistochemically positive for S-100, indicating neural cell origin. As neural polypoid lesion of the rectum, neurofibroma, perineurioma, schwannoma, and mucosal Schwann cell hamartoma were in the differential diagnosis. Histology and additional immunohistochemistry confirmed mucosal Schwann cell hamartoma. Mucosal Schwann cell hamartoma of the rectosigmoid junction or rectum can be a histological mimic of mucosal prolapse syndrome and other S-100 positive neural cell lesions; however, the lesion in the present case was correctly diagnosed with histology and immunohistochemistry.