Penile pseudomyogenic hemangioendothelioma: a rare case report with clinicopathologic features and multidisciplinary...

Pseudomyogenic hemangioendothelioma (PHE) is a rare vascular neoplasm of intermediate malignancy that predominantly affects the limbs and trunk of young adults. Genital localization, particularly penile involvement, is exceptionally uncommon and may lead to diagnostic challenges.

A 29-year-old man presented with a painful, ulcerative lesion on the ventral prepuce that had been present for 5 years. He initially underwent circumcision, and histopathologic evaluation of the surgical specimen suggested an undifferentiated malignant neoplasm. Despite surgery, symptoms persisted. Three months later, magnetic resonance imaging (MRI) revealed a penile mass infiltrating the corpora cavernosa, corpus spongiosum, and glans. Subsequent histopathologic re-evaluation with immunohistochemistry demonstrated co-expression of cytokeratins and endothelial markers (CD31, ERG), establishing the diagnosis of PHE. The tumor showed perineural and intravascular invasion with positive surgical margins. Given the extent of local disease and the complex anatomic location, a multidisciplinary team evaluated wide local excision, including the possibility of partial penectomy, versus systemic targeted therapy. The patient ultimately underwent partial penile resection, resulting in marked improvement in pain and overall clinical status.

Penile PHE can mimic other spindle cell neoplasms, necessitating immunohistochemistry for definitive diagnosis. Surgery with negative margins remains the mainstay of treatment, though it may compromise function in genital sites. Targeted therapies directed at FOSB-related molecular pathways may benefit from unresectable or multifocal disease.

There are only a limited number of cases reported worldwide of this rare neoplasm, and to our knowledge this represents the first reported case from Ecuador and the first from Latin America involving this anatomic site. It highlights the tumor's diagnostic complexity, potential for aggressive local behavior, and the importance of multidisciplinary management and long-term surveillance.