Pathology Quiz Case

Abstract

A 35-YEAR-OLD MAN PRESENTED WITH A 3-YEAR history of a small, soft nodule on the hairline of his left forehead area. With time, the mass had gradually increased in size to involve most of the left side of the forehead and scalp. Physical examination revealed a large, firm, solid soft tissue mass involving the left side of the scalp and forehead, with some extension to the left orbital rim and right side of the scalp. The mass had stretched the skin with an irregular contour. An area of ulceration involved the entire superior surface, exposing the underlying tissue with necrotic and hemorrhagic areas and emitting a fibrinopurulent discharge (Figure 1). There were no cranial nerve palsies or other focal neurologic findings. The patient deniedanyheadaches,visualorauditoryimpairments,memory problems, or syncope. The results of the rest of the examination were unremarkable. Computed tomography of the head demonstrated a 11.8 17.0 15.0-cm soft tissue mass on the scalp that was heterogeneous in density, with cystic and/or necrotic areas. There was a 1.0 0.6-cm region of bone erosion involving the outer table of the frontal bone (Figure2). The orbits were uninvolved. Microscopy of an incisional biopsy specimen revealed radial whorls of spindle cells producing a cartwheel or storiform pattern (Figure 3). The tumor infiltrated the subcutis, resulting in entrapment of isolated fat cells (Figure 4). Immunohistochemical stains showed that the tumor cells expressed CD34 but not S100 protein or pancytokeratin. What is your diagnosis?