Objective: To describe the imaging and histopathology of pseudomyogenic hemangioendothelioma.
Materials and methods: Five cases of pseudomyogenic hemangioendothelioma, which presented over the last 5 years, were retrieved from the files of the Royal National Orthopaedic Hospital. The imaging and histopathology were reviewed in all cases. Magnetic resonance imaging, which was available from all cases, was assessed for the following features: the number of lesions, location in soft tissue (superficial and or deep/subfascial) and bone, and the signal characteristics and morphology of individual lesions. Immunohistochemistry was performed in all cases to characterize the lesions.
Results: Four of the five patients had multiple lesions involving a single limb. Bone was involved in 3 of the 5 individuals. All tumors diffusely expressed ERG and cytokeratins AE1/3, but not MNF116. CD31 was weakly positive in 4 cases. INI-1 expression was retained in all cases. Imaging features included ill-defined, infiltrative lesions in subcutaneous fat with extension to the adjacent skin, poor- to well-defined intramuscular nodules and predominantly intracortical focal bone lesions with rare medullary involvement.
Conclusion: Pseudomyogenic hemangioendothelioma represents a distinct recently characterized tumor type presenting in young adults, with a tendency towards multicentric bone and soft tissue involvement.