Parosteal Lipoma of the Proximal Radius

Case Report

Austin J Musculoskelet Disord. 2016; 3(1): 1027.

Parosteal Lipoma of the Proximal Radius

John SH1, Chad CBS1, Kathleen SB1*, Valerie AF2, Marcia FB3 and Joseph B1

1Division of Musculoskeletal Oncology, Department of Orthopedic Surgery Rutgers, The State University of New Jersey-New Jersey Medical School, USA

2Department of Pathology and Laboratory Medicine, Rutgers, The State University of New Jersey-New Jersey Medical School, USA

3Department of Radiology Rutgers, The State University of New Jersey-New Jersey Medical School, USA

*Corresponding author: Kathleen S Beebe, Department of Orthopedics, Division of Musculoskeletal Oncology New Jersey Medical School Rutgers, The State University of New Jersey 140 Bergen St. Suite D-1610 Newark, NJ 07103, USA

Received: November 30, 2015; Accepted: January 19, 2016; Published: January 22, 2016


Parosteal lipomas and are described as surface osseous lipomas which are contiguous with the periosteum. They represent 15% of osseous lipomas and most occur in the fifth and sixth decades with a slight male predilection. To date, only 150 of these tumors have been reported in the literature. We present a rare case of Parosteal lipoma with cytogenetic correlation. The clinical implications of this lesion will also be discussed.

Keywords: Parosteal lipoma; Forearm; Tumor


Lipomas are common benign soft-tissue tumors, which are usually asymptomatic [1]. Grossly, they are encapsulated, yellow soft tissue masses that may also have other tissue components incorporated within them. These lipomas are named according to the coexisting tissues; such as angiolipoma, fibrolipoma andosteolipoma [2].

Osseous lipomas have been classified according to their site of origin: either within bone (intraosseous) or on its surface (juxtacortical). Surface osseous lipomas are subdivided into Parosteal and subparosteal lipomas, depending on their relationship to the bone periosteum [3]. To the best of the author’s knowledge, about Parosteal lipomas have been reported to date, representing less than 0.3% of allipomas. These unusual masses most frequently arise in the femur, tibia, humerus and radius [4,5].

Case Report

A 62 year old woman presented with a palpable mass in the anterior left proximal forearm. She had noticed the mass enlarging over the preceding year, but denied any pain or loss of function associated with anterior intraosseous nerve compression, such as loss of pincer grip. Physical examination revealed a fixed, nonpulsatile mass over the volar radius. The patient had full range of motion at theel bow, wrist and fingers, but did show a mild decrease in grip strength compared to the contra lateral hand. She denied any tenderness upon diffuse palpation.

Conventional radiographs of the left forearm displayed an oval density in the soft tissues volar to the radial shaft (Figure 1). Magnetic Resonance Imaging (MRI) done the same day demonstrated a welldefined mass composed of mostly fatty tissue, with diffuse areas of hypo intensity, consistent with cortical bone, which was contiguous with the cortical bone on the volar radial shaft (Figure 2). A wholebody bone scan showed increased activity in the region of the proximal radius, consistent with erosion of the radial cortex by the adjacent lesion.