Primary hemangioblastoma of rectum: a rare case report and review of literature.

PURPOSE: Hemangioblastoma is an uncommon tumor of uncertain histogenesis, primarily found in the central nervous system. However, extraneural cases have been reported in visceral organs such as the kidneys, pancreas, peritoneum, and liver. Hemangioblastoma occurring in the gastrointestinal tract is extremely rare, with only 4 cases can be retrieved. Here, we presented a case of rectal hemangioblastoma.

METHODS

A 59-year-old woman sought medical attention for altered stool consistency and the colonoscopy revealed a submucosal lesion in the rectum. Subsequently, she underwent endoscopic submucosal dissection. Grossly, the excised lesion was a broad-based polypoid mass measuring 1.2 × 0.8 × 0.8 cm, with a grayish-white appearance and no signs of hemorrhage or necrosis. Histologically, the tumor consisted of a rich network of thin-walled blood vessels interspersed with vesicular neoplastic cells, with minimal mitotic activity. Immunohistochemistry found that neoplastic cells were positive for D2-40, and β-catenin showed normal membranous staining pattern. No pathogenic mutations in the VHL gene were detected by NGS in this sample. However, we found genetic alterations in other genes potentially associated with the pathogenesis of hemangioblastoma, such as TSC, SDH and PTEN.

RESULTS

Based on the above findings, the diagnosis of hemangioblastoma was made. The differential diagnosis included hemangioma, lymphangioma, neuroendocrine tumor, metastatic renal cell carcinoma, perivascular epithelioid cell tumor, gastrointestinal stromal tumor, and well-differentiated liposarcoma.

CONCLUSION

This case underscored the importance of considering hemangioblastoma in the differential diagnosis of rectal submucosal lesions. It highlighted the need for a thorough diagnostic approach that integrates colonoscopic evaluation with histopathological examination, particularly in patients presenting with altered stool consistency or melena. Furthermore, the NGS results implicated that TSC, SDH and PTEN may contribute to hemangioblastoma development. These alterations could constitute a novel diagnostic signature, a premise that warrants definitive investigation through larger, multi-institutional studies.