Rachel Bass

Organizing thrombus is a well described histologic finding involving the reorganizing and recanalization of a healing thrombus. However, it is rarely large enough to be described on imaging. When the thrombus becomes sufficiently large, intravascular papillary endothelial hyperplasia (IPEH) must be considered. IPEH or Masson’s tumor is a benign, exuberant form of organizing thrombus that typically occurs in the soft tissues of the head, neck, and distal extremities. It can occur within a vessel, hematoma, or vascular mass and can mimic benign processes or malignant lesions such as angiosarcoma. Histopathological characteristics are needed for final diagnosis. The treatment is typically complete surgical resection with excellent prognosis. We report the case of a patient presenting with swelling in his left forearm in the same site as a previously treated left basilic vein thrombus. Ultrasound demonstrated a noncompressible, heterogeneous intravascular mass with internal vascularity. Subsequent MRI showed an enhancing mass centered in the left basilic vein with a flow void with the differential diagnosis of IPEH versus intravascular neoplasm. Percutaneous biopsy was performed with histology consistent with reactive vascular proliferation and organizing thrombus. The papillary architecture diagnostic of IPEH was absent. Regardless of final specific terminology, this case presents exuberant organizing thrombus as a benign cause of an enhancing intravascular mass. This patient was treated conservatively with no further intervention.

Intravascular papillary endothelial hyperplasia (IPEH), also known as Masson’s tumor, is an uncommon exuberant form of organizing thrombus that may occur within a vessel, vascular tumor, or hematoma and may change the imaging appearance to mimic an aggressive process. It must be distinguished pathologically from angiosarcoma. They have been most commonly reported within superficial soft tissue tumors, and rapid growth and effect on bone are rarely described. We present a case of a patient with a soft tissue hemangioma with IPEH with intraosseous extension that presented with a pathologic fracture of her right humerus with an aggressive appearing osseous lesion. CT and MRI demonstrated a multifocal ill-defined soft tissue mass throughout the right upper extremity with underlying cortical tunneling and scalloping of the proximal humerus. Similar imaging findings were also present in the distal humerus and ipsilateral scapula and evolved during her hospitalization. Following percutaneous biopsy revealing hemangioma with features of papillary endothelial hyperplasia with intraosseous extension, the patient died in the ICU secondary to unrelated septic shock. Diagnosis was confirmed at autopsy. Primary and secondary IPEH have been generally characterized as well-defined solitary masses, most often in the superficial soft tissues. This case of a deep soft tissue hemangioma with type II IPEH, intraosseous extension, and imaging findings of regional multicompartmental involvement is very unusual. Reporting of this case in the literature should be beneficial for pathologic correlation with similar confounding masses as well as propose a possible mechanism for intraosseous extension of soft tissue hemangiomas.

Prisons are in some significant respects similar to planetary stations. Their occupants live within a social environment that is confined, takes on its own culture with a strong interdependence and camaraderie between individuals, and contains within it huge latent talents in art, science, engineering, and other disciplines. Recognizing this potential, the Life Beyond project involves the prison population in designing settlements for the Moon and Mars. Involving ∼160 prisoners in Scotland, the project has led to two published books presenting strategies for the settlement of the Moon and Mars. Building on this, a set of course materials was devised for any prisoner anywhere to contribute ideas and plans for the human exploration and settlement of space. Here, we describe this project, the methods used, and the results. In addition to improving educational opportunities in prisons through space science and elements of astrobiology, the project demonstrates the potential for prisoners to contribute to space settlement by applying their experience of the prison space analog environment.