Progressively Multifocal Pseudomyogenic Hemangioendothelioma: A Longitudinal Case with Cutaneous and Probable Pulmonary Involvement

Introduction

Pseudomyogenic hemangioendotheliomas (PMHEs) are rare vascular neoplasms of intermediate malignancy, with fewer than 200 cases reported globally. They predominantly occur in males within the second and third decades of life, appearing as multiple local cutaneous lesions, treated often with wide local excision. While local recurrence is common, distant organ involvement is rare, with variable response to systemic treatments. Case Presentation: We recount a case of a 21-year-old male who presented initially with a pea-sized red, itchy papule on his left dorsolateral foot, that grew blue and painful within a couple months, at which time it was proven by excisional biopsy to be PMHE. The lesion regrew within 2 months, with PET-CT showing local spread to muscle and bone tissue and FDG uptake in pulmonary nodules and locoregional lymph nodes, thus necessitating a left below knee amputation for local control coupled with initiation of systemic therapies. The patient trialed both an mTOR inhibitor followed by a multi-tyrosine kinase inhibitor with relative stability in the size of existing FDG uptake regions, but with additional cutaneous lesions appearing locally within the left upper leg and distally within the mid-back within a period of 15 months.