Rare case of Intravascular papillary hemangioendothelioma presenting as Carpal tunnel syndrome.

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.

The rare case has been reported by Vrajesh J. Shah et al in ‘Skeletal radiology’ journal.

The patient is a 37-year-old right-hand dominant woman who first presented at an outside facility for examination of a radial, volar right wrist mass. She initially noted the hard mass in 2016. She experienced nerve-like pain, numbness, and tingling from her wrist to thumb with exercise. She denied any prior trauma. Electromyography did not reveal nerve damage. Magnetic resonance imaging (MRI) suggested a peripheral nerve sheath tumor.

At the time, the patient declined surgical intervention as her symptoms did not greatly impede her daily life. She presented to the author’s hospital 3 years later, reporting interval growth of the mass and pain with hyperextension loading and minor accidental collisions. Focused examination of her right hand and wrist revealed a 3.0 × 2.0-cm mobile mass at the volar aspect of the right wrist, just beneath the palmaris longus tendon in the distal forearm, which was mildly tender to palpation. No subjective sensory deficits were noted to light touch. The patient had full strength, and no thenar atrophy was appreciated. There was a negative Tinel sign over the mass.

Multiplanar multisequence MRI of the right wrist was obtained before and after 4.5 mL of an intravenous gadolinium-based contrast. This showed a lobulated, predominantly T2 hyperintense, heterogeneously enhancing mass measuring 2.0 cm transverse × 1.2 cm dorsal-volar × 3.1 cm in length along the volar-radial aspect of the distal forearm/wrist. T1-weighted sequences demonstrated the “split fat” and “tail sign” indicating the neural origin of the mass. T2-weighted sequences revealed small, rounded areas of intermediate to low signal with the mass noted. The mass was located along the course of the median nerve, deep to the palmaris longus and flexor carpi radialis tendons with nodular areas of internal enhancement and was reported to be consistent with a peripheral nerve sheath tumor. The patient elected to undergo elective surgical removal of the symptomatic, enlarging mass.

An extensive carpal tunnel approach was drawn, and an incision was made in the distal forearm ulnar to palmaris longus. After careful dissection of the superficial soft tissue to the volar forearm fascia with loupe magnification, the palmaris longus was radially retracted to expose the median nerve. A large, fragile, seemingly vascular mass was examined with the median nerve. Under microscopic magnification, a meticulous dissection of the fragile mass from the fascicles of the median nerve was performed. The tumor appeared to have a “bag of worms” network of infltrative vascular channels interdigitated among the fascicles of the median nerves. A carpal tunnel release was performed to prevent nerve compression from the inflammatory response secondary to extensive fascicular manipulation. The wound was then copiously irrigated and reapproximated.

Histopathology of the specimen revealed multiple irregularly contoured vascular caverns lined by endothelial cells with dense fibrous connective tissue septae, features suggestive of a cavernous hemangioma. Additionally noted within the vascular spaces were multiple small organizing thrombi and focally prominent papillary endothelial hyperplasia typical of IVPH.

The patient recovered well after her right median nerve release and extensive internal neurolysis with removal of the IVPH.

The authors concluded that – “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.”

Further reading:

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

Vrajesh J. Shah, Kerry Sung et al

Skeletal Radiology (2023) 52:1421–1426

https://doi.org/10.1007/s00256-022-04250-y