Intravascular Papillary Endothelial Hyperplasia (Masson's Tumor) of the Supraclavicular Region: Management of a Rare Case.

BACKGROUND Masson's tumor, also known as IPEH (intravascular papillary endothelial hyperplasia), is a rare benign vascular process, comprising approximately 2% of vascular tumors of the skin and subcutaneous tissue. IPEH presenting as a neck mass is rare, with only 5 reports of anterior neck mass and 7 cases of lateral neck lesions, of which 1 was in an external jugular vein aneurysm. To the best of our knowledge, the localization of intravascular papillary endothelial hyperplasia in the supraclavicular region is rarely reported. CASE REPORT We describe our management of a non-traumatic and non-painful mass on the right supraclavicular region in 24-year-old woman. Ultrasound revealed a heterogeneously hypoechoic mass with intense vascularization. Magnetic resonance imaging (MRI) showed a formation with lobulated contours and closely related to muscular layers of serratus anterior muscle. The findings of ultrasound-guided biopsy (FNA) were inconclusive. Complete removal of the mass was performed. Histopathological examination showed a well-circumscribed lesion with numerous small papillary structures. The papillae had hyalinized hypocellular cores covered by flattened endothelium. Immunohistochemical analysis showed endothelial positivity for CD34 and CD31. These features are typical of IPEH. No recurrence had occurred at 12 months after surgery. CONCLUSIONS The differential diagnosis of malignant tumors like angiosarcoma is important because the prognosis significantly differs. Surgical excision is the treatment of choice. In our experience, the size of the lesion and its critical landmarks have not influenced the outcomes of the surgical procedure in terms of potential functional damages.