Infraclavicular Spindle Cell Haemangioendothelioma Mimicking Peripheral Nerve Sheath Tumour: A Case Report

Haemangioendotheliomas are rare vascular tumours that exhibit a biological spectrum intermediate between benign haemangiomas and highly malignant angiosarcomas. The malignant variant, Spindle Cell Haemangioendothelioma (SCH), typically presents in soft tissues and is particularly uncommon in the infraclavicular region. Hereby, the authors present an unusual case of SCH, initially misdiagnosed as a nerve sheath tumour, and successfully managed with surgical excision. A 32-year-old female presented with progressive swelling of the right upper limb for the past six months, along with a mass in the right infraclavicular region that had been enlarging for four months. Imaging studies suggested a Peripheral Nerve Sheath Tumour (PNST), and a Tru-cut biopsy indicated a benign spindle cell lesion. Surgical excision was performed, and Histopathological Examination (HPE) confirmed the diagnosis of haemangioendothelioma (spindle cell subtype). The postoperative course was uneventful, and Adjuvant Radiotherapy (RT) was initiated due to positive tumour margins. RT was well tolerated, and the patient was asymptomatic at the six-month follow-up. Thus, although rare, malignant haemangioendothelioma should be considered in the differential diagnosis of soft tissue masses near vascular structures.