Pseudomyogenic hemangioendothelioma is a rare, recently described neoplasm that usually presents as multifocal lesions in a single extremity. The disease has demonstrated a high propensity for infiltrative growth and local recurrence but limited metastatic potential. Variations of histological appearance and immunohistochemical signatures have been described, but typically involve spindle or polygonal cells with nuclear atypia and neutrophilic infiltration. Here we present a case report of an 8-year-old female who presented with hip pain that was initially diagnosed and managed as a slipped capital femoral epiphysis (SCFE). Subsequent evaluation led to the diagnosis of pseudomyogenic hemangioendothelioma of bone. Due to the degree of osseous destruction, described patterns of local recurrence, and metastatic potential of this neoplasm, a wide resection with endoprosthetic reconstruction of the proximal femur was performed. This case highlights the importance of due diligence in the diagnoses of SCFE and bone tumors in young patients with abnormalities of the proximal femur, including consideration of the need for biopsy.
Pseudomyogenic hemangioendothelioma is a recently described neoplasm that most often presents as multifocal lesions in one extremity. Over the last several years, additional descriptions of this disease have emerged, with characterization of its clinical, ultrastructural, and histological components [
The patient is an eight year six month female who presented to a tertiary pediatric orthopaedic practice with a chief complaint of right hip pain for approximately one month after sustaining a fall. Prior to the fall she had been previously healthy and reported no antecedent right hip pain or any other medical problems. She was diagnosed with a slipped capital femoral epiphysis (SCFE) (
She was then referred to a musculoskeletal oncology service. Due to the non-diagnostic nature of her prior evaluations, she was taken to the operating room for an open biopsy through a lateral approach. Histologic evaluation showed foci of single and clustered epithelioid cells embedded within a fibrous stroma in the intertrabecular spaces. Reticulin stain demonstrated that most clustered cells were within vascular-type spaces. The cells immunostained variably for CD31 and cytokeratin AE1/AE3, with faint immunopositivity for smooth muscle actin (
She was taken to the operating room and a wide resection (
Pseudomyogenic hemangioendothelioma is rare, recently recognized disease entity. While the terminology “pseudomyogenic hemangioendothelioma” has only lately been established, multiple case series have reported on a constellation of clinical, morphological, and histological findings that likely describe similar disease entities
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In 1992, Mirra et al. [
Microscopically, the neoplastic lesions are composed of plump spindle or polygonal cells, occasionally rhabdomyoblast-like, with abundant eosinophilic cytoplasm, and more rarely epithelioid cells arranged in ill-defined sheets, nodules or fascicles. Nuclear atypia is generally mild to moderate, but is occasionally prominent, and the mitotic rate is low with rare necrosis. Prominent infiltration by neutrophils is commonly seen. The lesions typically show a limited infiltrative growth pattern [
Pseudomyogenic hemangioendothelioma classically affects young adults, rarely over the age of 40, with a strong male predominance. Tumors usually involve the extremities and are multicentric, involving multiple tissues planes, from dermal, subcutaneous, subfascial, and importantly, osseous. Previous case series suggest an indolent course for this type of tumor [
Sheng and Wang [
Pseudomyogenic hemangioendothelioma of bone is a rare tumor and the literature is not replete with guidance on how to optimally manage this disease. While the disease appears to have a limited metastatic potential, it has a high propensity for infiltrative growth and local recurrence. Given the local aggression and seemingly large area of disease in the proximal femur in the patient described in this case report, wide resection with endoprosthetic reconstruction was performed to minimize local recurrence. Especially due to the patient’s young age, implant choice was challenging, but ultimately a proximal femoral replacement with compressive osseointegration was chosen to allow for biologic ingrowth while minimizing bony resection.
This case also highlights the importance of due diligence in the diagnosis of SCFE in a young patient with osteolytic abnormalities of the proximal femur as well as close radiographic follow-up in the post-operative period following screw fixation. An appropriate work-up was obtained to investigate her abnormality further and a broad differential diagnosis was entertained. Ultimately, the histological specimen was diagnostic. Further, although the first CT-guided biopsy was inconclusive, high clinical suspicion led to an open biopsy of the lesion, which led to the definitive diagnosis and treatment. Clearly, additional clinical and basic scientific research is required before a consensus on the appropriate treatment of this rare tumor is rendered.
The Authors wish to thank Dr. Ronald Jaffe of the Childrens Hospital of Pittsburgh Department of Pathology for his guidance and assistance.
This work was supported by NIH grant 1K08CA177927-01, the Shadyside Hospital Foundation, Pittsburgh CureSarcoma, the Pittsburgh Foundation, and the Houy family in loving memory of Jonathan Houy.