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

Nonpolypous Hamartomas of the Gastrointestinal Tract: An Updated Review on Classification, Denominations, and Clinical Management

PURPOSE

To perform the first systematic report about histological subtypes of nonpolypous hamartomas of the gastrointestinal (GI) tract, from esophagus to anal canal.

DESIGN

From over 19,000 studies about hamartomas, most of them published as case series or case presentations, we have selected the most representative ones for the GI tract, excluding polyposis syndromes. To have a whole picture of these hamartomas, all of the data were combined with the personal experience of the authors who are GI pathologists.

RESULTS

The examined articles showed predominance of vascular and combined vascular and mesenchymal hamartomas. Arteriovenous hamartomas or Brunner gland hamartomas are mainly diagnosed in the small intestine, with preponderance for duodenum. Other malformations such cavernous hamartomas are more specific for the colorectal segments, whereas chondromatous hamartomas or those derived from the neural ectoderm were mostly reported in the esophagus. As newly recognized entities were admitted in the last years, misdiagnosis is frequent, and the best therapeutic approach is far to be known.

CONCLUSION

Even rare, hamartomas of the GI tract need to be differentiated from tumors and familial polyposis syndromes. Knowing their proper denominations and possible complications is valuable for gastroenterologists, pathologists, and surgeons, to be aware in the differential diagnosis.