< Back Biomechanics of Foot biomechanics-foot Previous Next

< Back Mallet Finger, Boutonnière Deformity mallet-finger-boutonniere-deformity Previous Next

< Back Dr. H. Bilgehan CEVIK Osteochondroma · Benign hamartomatous cartilaginous lesions derived from aberrant cartilage through the perichondral ring that may be in the form of solitary or associated with genetic conditions like Multiple Hereditary Exostosis (MHE) · They grow and mature according to typical enchondral ossification and do not occur in bones formed through membranous ossification (skull) Epidemiology · Common, approximately 35% of benign bone tumors and 10-15% of all bone tumors · Originating in early infancy, most cases are diagnosed in the first 2 decades of life · More common in males, 2 to 1 · They are most commonly sporadic · 15% of osteochondroma patients also have MHE , while some may have Trevor disease or Langer-Giedion syndrome. Localization · Most commonly occur in the long bones; femur > humerus > tibia · The most common area is around the knee (proximal tibia and distal femur) · Originating from the metaphysis, it tends to grow toward the diaphysis with skeletal growth · In flat bones, the ilium and scapula are frequent locations · Rare in the small bones of the hand and foot, ribs, and spine ·Solitary osteochondromas o Can arise because of trauma (e.g., Salter-Harris fracture), iatrogenic (e.g., surgery), and radiotherapy (the most typical radiation-induced benign bone tumor) [figure 6] o The inactivation of the EXT gene is restricted to the cartilage cap and occurs somatically · Both solitary and MHE are associated with loss-of-function mutations in the EXT1 (8q24) and EXT2 (11p11) genes, leading to decreased production of heparan sulfate by chondrocytes found at the physis · Individuals with the EXT1 mutation exhibit a more severe presentation than those with the EXT2 mutation, including a higher incidence of chondrosarcoma, a greater number of exostoses, increased limb malalignment, reduced range of motion in the forearms and knees, and more involvement of the pelvis and flat bones · MHE o Heredity is present in 2/3 of the cases o Shows AD inheritance; patients have a heterozygous germline EXT1/EXT2 mutation , while their tumors usually show a homozygous EXT mutation o The penetrance is estimated to be 96% in females and 100% in males Presentation · Most of the lesions are asymptomatic · The most common symptom is a painless mass that increases in size during skeletal growth · Occasionally, it may cause pain because of mechanical symptoms, including bursitis, tendinitis, or neurovascular compression Imaging Radiograph o Lesions on bone surfaces can be either pedunculated (narrow stalk) or sessile (broad base) , and they are continuous with the medullary cavity of the native bone, which is pathognomonic. o Pedunculated lesions grow toward the diaphysis o Sessile lesions have a higher risk of malignant transformation [ o Usually, the cartilage cap is radiolucent CT CT imaging confirms the findings visible on radiographs but provides superior visualization of medullary continuity and the cartilage cap. In some cases, enhancement may be observed along the septa between cartilage lobules. Ultrasound Ultrasonography can delineate the cartilage cap with high accuracy, appearing as a hypoechoic layer bordered by bone on the deep aspect and by overlying muscle or fat superficially. MRI MRI is the most sensitive modality for evaluating cartilage cap thickness (which is crucial for identifying malignant transformation), assessing bone or soft-tissue edema, and depicting adjacent neurovascular structures. On MRI, the cartilaginous cap demonstrates low to intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted sequences, consistent with cartilage elsewhere. A cap thickness exceeding 1.5 cm after skeletal maturity suggests possible malignant change, whereas in younger individuals, the cap can normally measure up to 3 cm. Following gadolinium contrast administration, benign osteochondromas typically show enhancement confined to the peripheral fibrovascular tissue covering the cartilage cap, while the cap itself remains non-enhancing. In contrast, chondrosarcomas often display internal septal enhancement between cartilage lobules. Pathology · Usually, a biopsy is not necessary for diagnosis [figure 13] · The cartilage cap consists of mature hyaline cartilage with well-defined fibrous perichondrium around the cartilage cap · In children, the transition between the bone and cartilage cap resembles a growth plate, showing endochondral ossification into mature bone; cartilage cap thickness is not a reliable indicator of malignant transformation in children (up to 1-3 cm thickness) [figure 14] · Cartilage cap thickness diminishes and may even be absent in older adults (usually 2-3 mm thickness) · In adults, a cartilage cap thickness of > 2 cm increases the risk of chondrosarcoma Staging · Growing stops after skeletal maturity · Malignant transformation to chondrosarcoma o The sudden onset of pain in adults with MHE should raise concerns about possible malignant transformation o Histological features alone are often inadequate for a definitive diagnosis of secondary chondrosarcoma arising from osteochondroma, which requires correlation with clinical and imaging findings o Mostly low-grade chondrosarcoma (90%) [figure 15] o Proximal lesions have a higher risk of undergoing malignant transformation compared to distal lesions; sessile lesions have a higher risk of malignant transformation; a cartilage cap thickness of > 2 cm increases the risk of chondrosarcoma o Occurs mostly in >50 years old o Malignant transformation of solitary osteochondroma to chondrosarcoma is rare, occurring in < 1% of cases [figure 16] o This transformation does not happen before puberty, and the risk increases to 5-10% in MHE o The risk of malignant transformation depends on the site, with the pelvis being the most common location [figure 17] Differential diagnosis · Bizarre parosteal osteochondromatous proliferation (Nora lesion ): Typically located in the hands; arises from the bone cortex and lacks medullary continuity · Florid reactive periostitis : Typically located in the hands, especially in proximal phalanxes; the cortex of the bone is typically intact · Supracondylar humerus spur : projects towards the elbow joint; the cortex of the bone is typically intact Treatment · Asymptomatic lesions [figure 18] o There is no indication for surgery; observation alone o The lesions in the trunk and limb girdles can be surgically removed to prevent the risk of secondary chondrosarcoma transformation [figure 19] · Symptomatic lesions o Marginal resection at the base of the stalk, including cartilage cap [figure 20] · Surgical removal of lesions near the epiphysis may cause injury to the growth plate; if feasible, surgery should be postponed until skeletal maturity · Secondary chondrosarcomas are treated as typical chondrosarcomas with wide surgical resection · Recurrence may be seen in 2-5% cases after resection References Fletcher CDM, Bridge JA, Hogendoorn PCW, Mertens F (eds). WHO Classification of Soft Tissue and Bone Tumours, 5th Edition. Lyon: IARC Press; 2020. Bovée JVMG. Multiple osteochondromas. Orphanet J Rare Dis. 2008;3:3. doi:10.1186/1750-1172-3-3. Ahmed AR, Tan TS, Unni KK, Collins MS, Wenger DE, Sim FH. Secondary chondrosarcoma in osteochondroma: Report of 107 patients. Clin Orthop Relat Res. 2003;(411):193–206. Murphey MD, Choi JJ, Kransdorf MJ, Flemming DJ, Gannon FH. Imaging of osteochondroma: Variants and complications with radiologic-pathologic correlation. Radiographics. 2000;20(5):1407–1434. Stieber JR, Dormans JP. Manifestations of hereditary multiple exostoses. J Am Acad Orthop Surg. 2005;13(2):110–120. Bovée JVMG, Hogendoorn PCW. Cartilage-forming tumours of bone and soft tissue and their differential diagnosis. Curr Diagn Pathol. 2002;8(6):332–339. Czajka CM, DiCaprio MR. What is the proportion of malignant transformation in hereditary multiple exostoses? Clin Orthop Relat Res. 2015;473(7):2355–2361. Legeai-Mallet L, Munnich A, Maroteaux P, Le Merrer M. Genetic counselling in hereditary multiple exostoses. J Med Genet. 1997;34(4):265–268. Coronal and axial MRI and CT images of the distal femur show a pedunculated osteochondroma arising from the metaphyseal region, demonstrating continuity of the cortex and medullary cavity with the underlying bone. The lesion has a well-defined cartilage cap, which appears low-to-intermediate signal on T1-weighted and high signal on T2-weighted sequences. No surrounding marrow edema or soft-tissue mass is seen, consistent with a benign osteochondroma. Osteochondroma pathology Previous Next

< Back Dr. İlkay TOSUN Dr. İlkay Tosun is a senior pathologist at the University of Health Sciences Ümraniye Training and Research Hospital, serving as the lead consultant for musculoskeletal system tumors. She completed her medical degree at Ege University Faculty of Medicine (2002) and her pathology residency at Haydarpaşa Numune Training and Research Hospital (2009) . Since 2013, she has been practicing as a pathology specialist and educator, contributing to diagnostic and academic development in orthopedic oncology and soft-tissue pathology. Education Ege University Faculty of Medicine , M.D. (2002) Haydarpaşa Numune Training and Research Hospital , Pathology Residency (2009) Ümraniye Training and Research Hospital , Başasistan / Training Consultant (2013–Present) Professional Experience Başasistan Pathologist , Ümraniye Training and Research Hospital (2013 – Present) Pathology Specialist , Balıkesir Atatürk State Hospital (2012 – 2013) Pathology Specialist , Şanlıurfa Siverek State Hospital (2010 – 2012) Assistant Doctor , Haydarpaşa Numune EAH (2005 – 2010) General Practitioner , Zümrütevler Health Center (2003 – 2005) Selected Research & Publications Clinical and Pathological Features of 31 Cases of Lipedematous Scalp and Lipedematous Alopecia , Eur J Dermatol , 2011 P16 Protein Expression in Gastrointestinal Stromal Tumors , HNEAH Medical Journal , 2012 Correlation of Serum Transaminase Values with Fibrosis Staging in Chronic Hepatitis , Turkiye Klinikleri J Med Sci , 2011 Approach to Primary Vertebral Tumors in Light of the 2020 WHO Classification , 2023 Biphenotypic Sinonasal Sarcoma with PAX3/FOXO1 Fusion , 2024 Clinical Interests Bone and Soft-Tissue Tumor Pathology Musculoskeletal Oncology Musculoskeletal Pathology milkaytosun@hotmail.com Previous Next

< Back Posterior Tibial Tendon Dysfunction (PTTD) posterior-tibial-tendon-dysfunction Previous Next

< Back Dr.Ahmet Müçteba Yıldırım Giant Cell Tumor (GCT) Overview GCBT is an aggressive benign bone tumour, classified as intermediate (locally aggressive) in the 2020 WHO classification. Accounts for 5–10% of all primary bone tumours. Typically affects individuals aged 20–40 years. Female > Male (1.3–2:1). Associated conditions: Noonan syndrome, Paget’s disease. Common Sites Most common: Knee region (distal femur, proximal tibia) Also seen in: Distal radius , proximal humerus , sacrum (most common axial site) Clinical Presentation Persistent pain (most common) Joint swelling, limited motion, or pathological fracture (5–10%) Palpable mass (if soft tissue extension exists) No constitutional symptoms Imaging Features X-ray: Eccentric, lytic lesion No sclerotic rim , no calcification Cortical expansion without periosteal reaction Wide transition zone in fibula/ulna Aggressive signs: Geographic destruction, soft tissue mass, fluid-fluid levels (if secondary ABC) CT: Detects lung metastases , evaluates axial involvement and trabecular pattern MRI: T1: Hypo- to isointense T2: Hyperintense, heterogeneous Shows soft tissue extension and blooming on GRE (hemosiderin) Campanacci Classification Used as a surgical guide. Differential Diagnosis Chondroblastoma: Epiphyseal, sclerotic rim, surrounding bone marrow oedema Aneurysmal Bone Cyst (ABC): May co-exist, lacks soft tissue mass Brown Tumour: Consider if high PTH Treatment Surgical Management (Extremities) Intralesional curettage + adjuvant (phenol, ethanol, cryotherapy, argon gas, high-speed burr) + PMMA or graft PMMA advantages: Exothermic necrosis, easier recurrence detection Risks: Subchondral damage → early osteoarthritis Wide resection: Indicated in Campanacci 3, distal ulna/proximal fibula Denosumab (pre-op): Used to shrink tumour for limb-salvage surgery in Campanacci 3 Management of Pelvic & Axial GCBTs Surgery carries high local complication risk Grade 1–2: Intralesional resection after radioembolization Grade 3: If feasible → Wide resection ± radioembolization If unresectable → Denosumab alone Radiotherapy: Only for inoperable cases (malignant transformation risk) Medical Therapy Denosumab (RANKL inhibitor): Pre-op or in inoperable patients Avoid in Grade 1–2 : Can reduce curettage efficacy and increase recurrence Risks: Malignant transformation with long-term use, osteonecrosis of jaw Bisphosphonates (e.g., zoledronic acid): Reduces tumour size Side effects: ONJ, atypical femur fracture, oesophagitis, hypo-/hypercalcemia Metastasis & Complications Lung metastases: Typically indolent; metastasectomy for progressive disease Recurrence: 20–50% within 3 years, higher in axial/distal radius sites Malignant transformation: Rare but severe (e.g., UPS or osteosarcoma, linked to denosumab) PMMA-induced osteoarthritis due to chondral necrosis References Siegel, G. W., & Biermann, J. S. Orthopaedic Knowledge Update®: Musculoskeletal Tumors 5 Kang, H. S., et al. Oncologic Imaging: Bone Tumors , Springer Choi, J. H., & Ro, J. Y. 2020 WHO Classification of Bone Tumors Bayram, S., et al. EFORT Open Rev , 2024;9(3):181–189 Campanacci Classification Giant cell tm. pathology Previous Next

BATIBAY Sefa Giray KAYA Ozcan CAMUR Savas VELİ Natig SAYGILI Selcuk SAGLAM Yavuz KARAYTUG Kayahan SERARSLAN YAGCIOGLU Bengül DUNKI Alper POLAT Omer OZKAN Korhan COBANOGLU Mutlu KAPICIOGLU Mehmet AYIK Omer REDDY A. Krishna BIRINCI Murat Dr. Ilkay TOSUN BULUT S. Sanem Dereli CEPNI Serdar Kamil YENIGUL Ali Erkan TASCI Murat KIZILKURT Taha AKTAN Cemil DINCER Recep OKAY Erhan KORKMAZ Murat TUNALI Onur KOC Ali BALCI Halil İbrahim DEMIREL Mehmet BAYRAM Serkan IYIGUN Abdullah SALDUZ Ahmet ESKARA Hakan YILDIRIM Ahmet Müçteba KANAY Enes KANAY CEVIK H. Bilgehan DEMIROZ Serdar AYCAN Osman Emre

< Back Distal Radius/Ulna Distal radius fractures are among the most common upper limb injuries. Management depends on fracture pattern, displacement, articular involvement, and patient factors. Distal radius fractures are common, particularly in older adults following low-energy falls. Classification systems like AO and Frykman are useful for assessment. Treatment options include conservative casting, closed reduction with percutaneous pinning, and open reduction with internal fixation (typically volar plating). Ulnar styloid fractures or distal radioulnar joint (DRUJ) involvement should also be evaluated. distal-radius-ulna Previous Next

< Back Physical Examination of the Knee Previous Next

< Back Dr. Yasin SAYAR Arthroplasty Previous Next

< Back Dr. Hakan ESKARA Soft Tissue Tumor Classification The WHO introduced the classification of soft tissue and bone tumors (fifth edition) in 2020. The new WHO classification of soft tissue and bone tumors, introduced in 2020 (fifth edition), has made significant improvements in classification and introduced many new diagnoses. Histologic Subtypes of Soft Tissue Sarcomas 1. Undifferentiated Pleomorphic Sarcoma (UPS) Previously Malignant Fibrous Histiocytoma (MFH) . High-grade pleomorphic tumor without identifiable line of differentiation. Common sites: thigh, buttock, shoulder girdle, retroperitoneum . Aggressive local behaviour; lung metastases common. Treatment: wide excision ± radiotherapy; chemotherapy in selected cases. 2. Malignant Peripheral Nerve Sheath Tumor (MPNST) Originates from peripheral nerves or pre-existing neurofibromas . Strongly associated with Neurofibromatosis type 1 (NF1) . Rapidly enlarging deep-seated mass along nerve pathways. S-100 and SOX10 positive in subset. Prognosis: poor; 5-year survival <50%. 3. Synovial Sarcoma Typically affects young adults (15–40 years) , often around large joints (especially knee, ankle). Despite name, does not arise from synovium . t(X;18)(p11;q11) translocation → SYT-SSX fusion. Histology: biphasic (epithelial + spindle cell) or monophasic. Treatment: surgery + radiotherapy ± chemo (if high-grade or metastatic). 4. Liposarcoma Most common soft tissue sarcoma in adults. Occurs in thigh and retroperitoneum . Subtypes: Well-differentiated (low grade, local recurrence) Myxoid/round cell (t(12;16), intermediate grade) Pleomorphic (high grade, aggressive) Treatment: wide excision; radiotherapy for high-grade disease. 5. Rhabdomyosarcoma Skeletal muscle–derived tumor; most common STS in children. Subtypes: embryonal, alveolar, pleomorphic. Markers: desmin, myogenin, MyoD1. Treatment: multimodal — surgery + radiotherapy + chemotherapy. 6. Fibrosarcoma Malignant spindle-cell tumor producing collagen . Often arises in deep soft tissues of extremities or trunk . Histology: herringbone pattern. Management: wide excision ± radiotherapy. Recurrence common; metastasis via hematogenous route. 7. Leiomyosarcoma Originates from smooth muscle cells (vessels, uterus, GI tract, soft tissue). Common in retroperitoneum and large veins . Markers: SMA, desmin, h-caldesmon positive. Prognosis: size and grade dependent. 8. Epithelioid Sarcoma Occurs in young adults , often distal upper extremities (hand, forearm). Mimics granulomatous or epithelial lesions. Loss of INI1 (SMARCB1) expression diagnostic. Tendency for local recurrence and lymphatic spread. 9. Angiosarcoma Malignant endothelial tumor. May arise spontaneously or post-radiation . Common sites: skin (scalp/face of elderly), breast, liver . CD31, CD34, ERG positive. Highly aggressive, poor prognosis. 10. Dermatofibrosarcoma Protuberans (DFSP) Low-grade, locally aggressive tumor of dermal fibroblastic origin . t(17;22) → COL1A1–PDGFB fusion. Slow-growing plaque or nodule on trunk or proximal extremities . Treatment: wide local excision or Mohs surgery . Recurrence common, metastasis rare. References: Coindre JM. Histologic classification of soft tissue sarcomas (update and perspectives). Histopathology. 2014;64(1):51–70. Fletcher CDM, Bridge JA, Hogendoorn PCW, Mertens F. WHO Classification of Tumours of Soft Tissue and Bone, 5th Edition (2020). Coindre JM, Terrier P, Guillou L, et al. Predictive value of grade for metastasis development in the main histologic types of adult soft tissue sarcomas. Cancer. 2001;91(10):1914–1926. Chibon F. The genetics of soft tissue sarcoma: from normal mesenchymal cells to malignant sarcomas. Nat Rev Cancer. 2013;13(8):545–558. Jo VY, Fletcher CDM. WHO classification updates on soft tissue and bone tumours. Histopathology. 2014;64(1):38–49. Widemann BC, Italiano A. Biology and management of malignant peripheral nerve sheath tumor. Neuro Oncol. 2018;20(6):763–773. Helman LJ, Meltzer P. Mechanisms of sarcoma development. Nat Rev Cancer. 2003;3(9):685–694. Weiss SW, Goldblum JR. Enzinger and Weiss’s Soft Tissue Tumors. 7th ed. Philadelphia: Elsevier, 2020. Thway K, Fisher C. Leiomyosarcoma: recent advances and diagnostic approach. Histopathology. 2015;67(5):701–711. Sirvent N, Maire G, Pedeutour F. Chromosome translocations in dermatofibrosarcoma protuberans. Hum Pathol. 2003;34(12):1293–1301. Soft Tissue Tumor Classification Group Benign Intermediate (Local Agressive) Malignant Adipocytic Lipoma, Lipomatosis, Angiolipoma, Hibernoma vb. Atypical lipomatous tumor Well-diff. liposarcoma, Dediff. liposarcoma, Myxoid liposarcoma vb. Fibroblastic / Myofibroblastic Nodular fasciitis, Elastofibroma, Fibroma of tendon sheath vb. Palmar/Plantar fibromatosis, Desmoid-type fibromatosis, Dermatofibrosarcoma protuberans vb. Fibrosarcoma NOS, Myxofibrosarcoma, Sclerosing epithelioid fibrosarcoma vb. Fibrohistiocytic Tenosynovial giant cell tumor Plexiform fibrohistiocytic tumor, Giant cell tumor of soft parts Malignant tenosynovial giant cell tumor Vascular Synovial hemangioma, Epithelioid hemangioma, Lymphangioma vb. Kaposiform hemangioendothelioma, Retiform hemangioendothelioma, Kaposi sarcoma vb. Epithelioid hemangioendothelioma, Angiosarcoma Pericytic Glomus tumor NOS, Myopericytoma, Angioleiomyoma — Malignant glomus tumor Skeletal muscle Rhabdomyoma — Rhabdomyosarcoma (Embryonal, Alveolar, Pleomorphic, Spindle cell vb.) Chondro-osseous Chondroma — Extraskeletal osteosarcoma Peripheral nerve sheath Schwannoma, Neurofibroma, Perineurioma, Granular cell tumor vb. — Malignant peripheral nerve sheath tumor, Melanotic variant vb. Uncertain differentiation Myxoma, Angiomyolipoma vb. Haemosiderotic fibrolipomatous tumor, Atypical fibroxanthoma vb. Synovial sarcoma, Epithelioid sarcoma, Clear cell sarcoma, Undifferentiated sarcomas vb. Undifferentiated small round cell — — Ewing sarcoma, CIC-rearranged sarcoma, Sarcoma with BCOR alterations Intraosseos Lipoma Ochronosis pathology Previous Next