Intravascular papillary hemangioendothelioma disguised as a peripheral sheath tumor of median nerve at the wrist: a case report and literature review.

Background: Intravascular papillary hemangioendothelioma (IVPH) is a benign lesion previously reported in the nasal cavity, neck, upper extremities, and breast. Diagnosis with cross-sectional imaging can prove difficult, with histopathological examination necessary for diagnosis. IVPH resulting in carpal tunnel symptoms is quite rare.

Case Presentation: We report the case of a 37-year-old woman who presented with a radial, volar right wrist mass enlarging over the span of 5 years. She noted numbness and tingling in her wrist and thumb, exacerbated by minor accidental collisions and wrist hyperextension. There was no antecedent trauma. On examination, a mildly tender, mobile mass was evident at the volar aspect of the right wrist. Magnetic resonance imaging (MRI) with contrast demonstrated a lobulated, predominantly T2 hyperintense, heterogeneously enhancing mass thought to be a peripheral nerve sheath tumor. The patient elected for surgical excision of the mass, and the histopathological examination showed organizing thrombi with prominent papillary endothelial hyperplasia. At the 2-month follow-up, the patient had full range of motion of her fingers and wrist, with subjectively normal sensation in the distribution of the median nerve.

Conclusion: Carpal tunnel syndrome, in exceedingly rare occasions, can result from an IVPH. MRI findings may be confused with more common entities. Histopathological confirmation remains necessary for conclusive diagnosis.