Posttraumatic intraosseous epidermoid inclusion cyst. A case report and short literature review

Epidermoid bone inclusion cysts are pathological structures bordered by a layer of stratified squamous epithelium containing keratin debris. They are also called epidermal bone cysts. Intraosseous epidermoid cysts are rare entities; these lesions may occur as a result of trauma (puncture wound or pressure erosion).They appear to be well defined, translucent lytic lesions with sclerotic margins on imaging studies. The most frequent sites affected are: the distal phalanx and the calvaria - intradiploic, but a few cases of larger bone involvement have been reported. The imagistic differential diagnosis of this lesion includes intraosseous extension of a glomus tumor, enchondroma, osteoid osteoma, acral metastases, some primary vascular bone tumors, giant cell reparative granuloma, subungual nodular melanoma or other lytic non-neoplastic lesions such as osteomyelitis. We present the case of a 70-year-old man experiencing anxiety and pain due to distal phalanx expansion of the IV digit, following hand trauma. An X-ray was performed, showing a radiotransparent lesion located in the distal phalanx. An intramedullary inclusion cyst must be taken into account as a clinical differential diagnosis. Due to the extensive destruction of the distal phalanx, amputation was necessary. Gross examination of the surgical specimen revealed a cystic lesion that contained whitish, creamy material with extensive necrotic areas. Microscopic examination revealed a ruptured intraosseous epidermoid inclusion cyst, which was successfully excised.

Benign Vascular Bone Tumors

The classification of vascular tumors of the skeleton can be thought of as a spectrum of disease including both benign and malignant entities. Chapter 60 focuses on the benign entities, hemangioma and epithelioid hemangioma. The term hemangioma refers to a collection of blood vessels and vascular spaces, perhaps better classified as a slow-flow vascular malformation. Epithelioid hemangioma is a rare and controversial entity that may be confused with its malignant counterpart, the epithelioid hemangioendothelioma. This chapter will describe the clinical, pathophysiological, and imaging features of these benign vascular bone tumors, with a brief mention of treatment strategies. Familiarity with the imaging appearances and characteristics of these entities is essential in order to guide clinical management and to avoid unnecessary investigation into clearly benign lesions.

Malignant Vascular Bone Tumors

The organization of vascular bone tumors can be thought of as a spectrum of disease including both benign and malignant entities. Chapter 61 focuses on the malignant tumors, which have elicited much controversy and debate. These include 2 vascular tumors of bone recognized by the World Health Organization: epithelioid hemangioendothelioma and angiosarcoma. Although there are no characteristic imaging features that would obviate the need for biopsy of these entities, they may present with multifocal bone lesions, which can suggest the diagnosis of a vascular tumor. This chapter will describe the clinical, pathophysiological, and imaging features of these malignant vascular bone tumors, with a brief mention of treatment strategies.

Metastatic lung angiosarcoma from a femoral subperiosteal origin

Primary malignant vascular bone tumors are unusual and include hemangioendothelioma, epitheloid hemangioendothelioma and angiosarcoma. Although few cases of primary bone angiosarcomas have been reported, those of femoral origin are even more infrequent. Such tumors diagnosis may be challenging due to their radiographic and histologic variety. We present a case of a 24-yearold woman with a subperiosteal diaphyseal angiosarcoma originating from the femoral bone and metastatic to the lung at the time of diagnosis. The clinical, histological and radiological features of this extremely rare lesion are presented.