The back pain is suggestive of an underlying inflammatory condition, such as seronegative spondyloarthropathy, likely ankylosing spondylitis.
Could she be experiencing an autoimmune storm resulting in manifestations of different autoimmune disease and resulting in a malignancy? Mammograms and pap smears testing were normal. She had not yet undegone colonoscopy.
Discussion
Our patient had a biopsy-proved diagnosis of chondromyxoid fibroma (CMF) of the manubrium, presenting with clinical manifestations of scleroderma, ankylosing spondylitis and lupus-like features. To our knowledge, this is the first reportable case of CMF presenting with overlap syndrome.
CMF is a benign neoplasm accounting for less than 1% of all bone tumors. It has a predilection for men in the second and third decades of life with the metaphyseal regions of the long bones of the lower extremities as the favored sites of occurrence. Other sites include the small bones of the feet and the ilium.1
Radiographically, CMF manifests as an eccentrically situated, well-circumscribed, oval metaphyseal lesion parallel to the long axis of the bone. On MRI, depending on the varying amounts of myxoid and cartilage tissue, the center of the tumor is hyperintense on T2-weighted spin-echo images and short inversion time inversion recovery sequences. The typical aspects of chondroid, fibrous and myxoid tissues are not present in each histological specimen. Therefore, a small biopsy could lead to a false-negative diagnosis.
The tissue manifestations, areas with large numbers of cells with loose connective tissue stroma penetrated by lobulated areas of chondroid material with increased numbers of cell nuclei at the periphery of the chondroid lobules with plump hyperchromatic nuclei, are characteristic of CMF. Treatment in most of the reported cases consists of intralesional curettage. Excision with or without bone grafting is often performed.2
Association between antecedent autoimmune diseases and malignancy has been reported in autoimmune diseases, such as systemic lupus erythematosus, dermatomyositis and rheumatoid arthritis, systemic sclerosis and Sjögren’s syndrome. Patients with malignancies may develop autoimmune and rheumatic manifestations by induction of autoimmunity characterized by the generation of autoantibodies against a wide range of autoantigens.3 Sera of patients with malignancies were found to bind antinuclear autoantibodies, DNA, histones, Ro, La, Sm and RNP.4
Patient’s Course
The patient underwent excision of the tumor with bone grafting.
Final Diagnosis
Primary chondromyxoid fibroma of the sternum is quite rare, with only six cases documented in the literature (see Table 1). To our knowledge, this is the first reportable case of CMP presenting with undifferentiated connective tissue.
