Osteoid osteomas of the hands and feet: a series of 71 cases.

Osteoid osteomas typically arise in the long bones of extremities. Patients often report pain relieved by NSAIDS, and radiographic findings are often sufficient for diagnosis. However, when involving the hands/feet, these lesions may go unrecognized or misdiagnosed radiographically due to their small size and prominent reactive changes. The clinicopathologic features of this entity involving the hands and feet are not well-described. Our institutional and consultation archives were searched for all cases of pathologically confirmed osteoid osteomas arising in the hands and feet. Clinical data was obtained and recorded. Seventy-one cases (45 males and 26 females, 7 to 64 years; median 23 years) arose in the hands and feet, representing 12% of institutional and 23% of consultation cases. The clinical impression often included neoplastic and inflammatory etiologies. Radiology studies demonstrated a small lytic lesion in all cases (33/33), the majority of which had a tiny focus of central calcification (26/33). Nearly, all cases demonstrated cortical thickening and/or sclerosis and perilesional edema which almost always had an extent two times greater than the size of the nidus. Histologic examination showed circumscribed osteoblastic lesions with formation of variably mineralized woven bone with single layer of osteoblastic rimming. The most common growth pattern of bone was trabecular (n = 34, 48%) followed by combined trabecular and sheet-like (n = 26, 37%) with only 11 (15%) cases presenting with pure sheet-like growth pattern. The majority (n = 57, 80%) showed intra-trabecular vascular stroma. No case showed significant cytology atypia. Follow up was available for 48 cases (1-432 months), and 4 cases recurred. Osteoid osteomas involving the hands and feet follow a similar age and sex distribution as their non-acral counterparts. These lesions often present with a broad differential diagnosis and may initially be confused with chronic osteomyelitis or a reactive process. While the majority of cases have classic morphologic features on histologic exam, a small subset consists solely of sheet-like sclerotic bone. Awareness that this entity may present in the hands and feet will help pathologists, radiologists, and clinicians accurately diagnose these tumors.

A peptoid interleukin-15 receptor antagonist suppresses inflammation and arthritis in mice.

Objective: To discover a novel peptoid antagonist that targets the interleukin-15 (IL-15) receptor and to evaluate its therapeutic efficacy in the treatment of inflammation and arthritis. Methods: A new compound (IFRA3, interleukin-15 receptor antagonist 3) was discovered using a unique on-bead two-colour combinatorial cell screening of a peptoid library. The interaction of IFRA3 with IL-15 receptor was assessed by in vitro pull-down and thermal shift assays. The efficacy of IFRA3 in treating inflammation and arthritis was evaluated in mouse models. Results: IFRA3Q1 (a tetrameric derivative of IFRA3) inhibited the activity of IL-15 and suppressed CTLL-2 cell proliferation (which depends on IL-15 activity). IFRA3Q1 exhibited strong in vivo anti-inflammatory activity in carrageenan-induced inflammation in mice. Furthermore, IFRA3Q1 inhibited collagen-induced arthritis in DBA/1J mice. Conclusion: By binding to and inhibiting the function of IL-15 receptor, IFRA3Q1 exhibited significant anti-arthritis activity. Our findings suggest that IFRA3Q1 represents a new paradigm for arthritis therapy by targeting IL-15 signalling.

Sternoclavicular joint pseudotumor: a clinicopathologic and radiologic study of 25 cases occurring in patients without prior neck dissection.

Pseudotumors of the sternoclavicular joint are rare, poorly characterized pseudoneoplastic lesions previously reported in association with prior neck dissection and thought to result from mechanical instability of the muscles of the shoulder girdle. We report 25 examples of this distinctive process, occurring in patients without a history of neck dissection, typically sent in consultation out of concern for a primary bone or soft-tissue tumor. Cases occurred in 14 women and 11 men (median = 68 years of age) and involved the sternoclavicular joint (17 cases), sternomanubrial joint (2 cases) or other nearby locations (6 cases). The masses ranged from 0.4 to 6.4 cm in size (median = 2.2 cm). Twenty-one patients (84%) had a clinical history of osteoarthritis involving other joints. Clinical follow-up (16 patients; mean = 11.4 months; range = 2-40 months) was uniformly benign, without evidence of recurrent disease. Radiologic review showed changes of osteoarthritis, often with cystic change. Pathologic features included degenerating cartilage, fibrinoid debris, pseudocyst formation, and florid proliferation of myofibroblasts and capillaries. The differential diagnosis of sternoclavicular/sternomanubrial pseudotumors centers around cartilaginous tumors of bone, in particular chondrosarcoma. Careful clinical, radiographic, and pathologic correlations are essential in arriving at the correct diagnosis and avoiding overtreatment.