Colonic Perineurioma Presenting as a Small Subepithelial Lesion With Distinctive Endoscopic Findings

Area of Science:

• Gastroenterology
• Surgical Pathology
• Oncology

Background:

• Colonic subepithelial lesions are often detected during routine colonoscopies.
• Differentiating benign from malignant lesions is crucial for appropriate management.
• Perineuriomas are rare tumors typically found in peripheral nerves, but can occur in the colon.

Purpose of the Study:

• To report a case of colonic perineurioma.
• To discuss diagnostic clues and the importance of histopathological evaluation for this rare entity.

Main Methods:

• A screening colonoscopy identified a 5-mm sigmoid colon lesion.
• Magnifying narrow-band imaging was used for in-vivo characterization.
• Cold snare polypectomy was performed for diagnosis and treatment.
• Histopathological and immunohistochemical analyses were conducted.

Main Results:

• The lesion exhibited features of a benign peripheral nerve sheath tumor.
• Immunohistochemistry confirmed positivity for vimentin and GLUT-1, with a low Ki-67 index.
• Findings were consistent with colonic perineurioma.

Conclusions:

• Colonic perineurioma is a rare differential diagnosis for small subepithelial lesions found during colonoscopy.
• Subtle endoscopic clues like reduced crypt density and arborizing vessels may be present.
• Definitive diagnosis relies on comprehensive histopathological and immunohistochemical assessment.