A Lytic Bone Lesion in the Phalanx of an 18-year-old Man

• DOI: 10.1097/blo.0b013e31802d6d57
• Publication Date: 2006-11-22T17:14:18Z
• Authors: Shilpa Shah; Shiwan K Shah; Carl Mogil; Stephen M Horowitz
• Keywords: Palpation; Phalanx; Presentation (obstetrics); Middle finger

HISTORY AND PHYSICAL EXAMINATION An 18-year-old man presented with a small bump that he first noticed about 2 weeks before on the dorsal aspect of middle phalanx immediately distal to proximal interphalangeal joint his right finger. The was associated tenderness palpation. However, moving did not aggravate pain. patient had questionable history trauma, noting once injured hand in van door but sure which finger injured. Initial radiographs indicated lytic lesion (Fig 1). Radiographs at 3 months showed expansion 2) and referred an orthopaedic oncologist. Physical examination time revealed swelling palpation phalanx.Fig 1A: B. (A) Dorsovolar (B) lateral show presentation. Note area base third digit.Fig 2: A dorsovolar radiograph shows after increase size definite expansile remodeling.Based history, physical findings, imaging studies, what is differential diagnosis? IMAGING INTERPRETATION Frontal 1A) 1B) radiographic views located eccentrically along ulnar margin cortical thinning question disruption, no clear fracture. Three original presentation, further mild cortex 2). In addition, there irregularity surface, suggesting healing pathologic DIFFERENTIAL DIAGNOSIS Enchondroma Giant cell reparative granuloma Chondroblastoma Aneurysmal bone cyst tumor We performed surgical biopsy definitive surgery as frozen section 3). Based examination, initial radiographs, histology, most likely diagnosis how should it be treated?Fig 3A: Photomicrographs histologic sections lesion. giant cells among background mononuclear scattered trabeculae reactive (Stain, hematoxylin eosin; magnification, ×5) two populations cells: one spindle-shaped nuclei (the actual neoplastic cells) plump resembling those ×40).See page 273 for treatment. Continuation ORP conference from 272. HISTOLOGY diffuse interspersed 3A). Some nuclei, while others oval similar 3B). There were occasional mitotic figures trabecular bone. DISCUSSION TREATMENT symptomatic benign-appearing includes enchondromas, granulomas, chondroblastomas, aneurysmal cysts, tumors (GCTs). Certain features help differentiate these entities (Table 1).TABLE 1: Radiographic Histologic Features Possible Differential DiagnosesGCTs are benign yet locally aggressive tumors, rarely (2%) metastasize lungs.11 This metastasis lung considered by some implants true metastasis.5,12,21 Rarely, GCTs have evidence malignancy. such case, they malignant tumors. Enchondromas common hand; however, eccentric location our typical enchondromas. enchondromas tend diaphyseal, opposed metaphyseal-epiphyseal distribution seen patient.4,7,14,15,20 Our lacked central sclerotic rim chondroblastoma.8,19 eccentric, expansile, compatible granulomas metaphy-seal-diaphyseal distribution.13,17,25 cysts radiographically appear GCT often coexist GCT. Thus, fact (eg, blood-filled spaces) found helped rule out this diagnosis.4 Hand lesions account only 2% 5% all GCTs.6 Specifically, phalangeal GCTs.22,26 More commonly, involve femur, tibia, radius, humerus, fibula, pelvis, sacrum, or spine.8,21,26,27 slightly more female patients their 30s 40s; younger than 19 years less frequently affected.3,11,26 hands younger. Pathologically, consist three major identical cells, multinucleated cells. latter derived mesenchymal stem resemble osteoblasts/fibroblasts. They release various factors, monocyte chemoattractant protein-1, osteoclast differentiation factor, macro-phage colony-stimulating attract cause monocytes into osteoclasts then cells.10,19,21,24 Clinically, present swelling, warmth, pain, initially movement, rest.8,21 may also become earlier, aggressive, recur, multifocal other locations.1,11,22,26 hand, locations, well-defined metaphyseal/epiphyseal extending subchondral bone.9 These purely (though pseudotrabeculations due endosteal scalloping present). Cortical destruction (potentially discontinuous) layer subperiosteal new formation present, without fracture periosteal reaction.3,13,21 contrast classical appearance, centrally because bones,11,26 making harder distinguish enchondroma, located.20 biggest concern local recurrence. Surgical options include curettage high-speed burring grafting, en bloc resection, wide excision, single double ray amputation. case series reported Averill et al,2 amputation recurrence, compared 43% recurrence rate resection 90% curettage. As aggressiveness tumor, Patel al16 suggest partial breakthrough. attempt decrease curettage, adjuvant agents (liquid nitrogen, phenol, hydrogen peroxide, alcohol, zinc chloride) been used kill remaining cells.21,27 use cement instead grafting rates, heat released during polymerization methylmethacrylate residual Other advantages ability detect recurrences earlier immediate stabilization precluding need prolonged immobilization/splinting. alters architecture theoretically predisposes adjacent degenerative disease.4,23 Careful postoperative clinical followup important. Recurrence radiography monitored. normal resorption graft material make difficult tends occur diaphyseal side articular cartilage acts barrier.18 With cement, lucent develops around vascular injury reaming, thermal polymerization, direct cytotoxic effect methylmethacrylate, stimulation macrophages. generally 1 mm. develop body's response foreign body.18 If complete unlikely 4). presence incomplete indicative normally has between 8 surgery. On lysis greater 5 mm suggested study predict recurrence.18 magnetic resonance imaging, demonstrated areas signal abnormalities characteristic (commonly high T2 low T1 signal) cement.Fig 4: postoperatively. removed defect filled cement. region (< 1-2 mm).The treated excision margins. coated cavity irrigated it, post-operatively reveal 4), chest do metastasis. good function able totally flex joint. Acknowledgments authors thank Neil Roach, MD, John MacKenzie, University Pennsylvania, Department Bone Radiology, assistance.