General Pathology- MSK module

• Osteosarcoma may have varying components: cartilaginous (“chondroblastic osteosarcoma”), spindled cells, (“fibroblastic osteosarcoma”), giant cells, etc.
• Osteoblastoma often presents with pain or nerve compression symptoms, but not relieved by NSAIDs.
• Treatment for Osteosarcoma includes pre-operative chemotherapy, resection, and post-operative chemotherapy.
• Osteosarcoma is an infiltrative growth, often high-grade cytologic atypia.
• Histologic response to neoadjuvant chemotherapy is one of the most important prognosticators of survival, with a good response being >90% necrosis.
• Osteosarcoma frequently has TP53 and RB1 mutations, increasing the risk in Li-Fraumeni syndrome and hereditary retinoblastoma.
• Osteoblastoma is a benign tumor that is often found in the spine, particularly the neural arch, and is morphologically similar to osteoid osteoma but has growth potential and generally exceeds 2 cm in size.
• Osteosarcoma is an aggressive tumor with local growth and rapid hematogenous dissemination, most frequently to the lungs.
• Osteoid Osteoma often presents with night pain relieved by NSAIDs.
• Osteoid Osteoma is a benign tumor that is often found in the cortex of long bones and is less than 2 cm in size, with a central nidus composed of microtrabecular woven bone rimmed by plump, bland osteoblasts in vascularized stroma.
• McCune-Albright syndrome is a condition that includes fibrous dysplasia, café-au-lait macules, and endocrinopathies.
• Osteoid Osteoma occurs in a 15-year-old male.
• Osteosarcoma is most common in the metaphysis of long bones near the knee, and imaging shows permeative bone destruction with fluffy immature mineralization and tumor ossification: Codman’s Triangle.
• Osteosarcoma is a high-grade sarcoma in which the tumor cells produce bone, requiring neoplastic bone formation on microscopy for diagnosis, and is the most common primary bone sarcoma.
• Biallelic inactivation of EXT1 or EXT2 is present in osteochondroma.
• Enchondroma/Chondroma often has IDH1 and IDH2 mutations.
• ACT has an abundant cartilaginous matrix (usually hyaline, but sometimes partially myxoid), with lobular growth and entrapment of preexisting bone; increased cellularity, but bland condensed nuclei.
• Chondrosarcoma, grade 2/3 does not produce osteoid by tumor cells.
• Enchondroma/Chondroma is often treated with curettage if symptomatic.
• Atypical Cartilaginous Tumor (ACT) is locally aggressive and can progress, but does not metastasize.
• Enchondroma/Chondroma is frequently found in the metaphysis of the short tubular bones of the hands.
• ACT is found in the appendicular skeleton (easier to resect) and Chondrosarcoma, grade 1 is found in the axial skeleton (harder to resect).
• Enchondroma/Chondroma is a benign, relatively common hyaline cartilage neoplasm arising within the medullary cavity (enchondroma) or if from hyaline cartilage, it is chondroma.
• Osteochondroma is continuous with the medullary cavity and cortex of bone.
• Cartilage is a 20-year old male with hip joint discomfort.
• Osteochondroma is often found on the metaphysis of long bones near the knee.
• Chondrosarcoma is a malignant tumor that can progress and metastasize.
• Chondrosarcoma, grade 2/3 has increased cellularity, more myxoid matrix, and mitoses.
• Osteochondroma is benign, has a cartilage cap with growth plate-like architecture, and an underlying stalk with medullary and cortical bone.
• Germline mutations in EXT1 are present in hereditary multiple osteochondroma syndrome.
• Enchondroma/Chondroma has an abundant hyaline cartaginous matrix and is hypocellular, with chondrocytes in sharp-edged lacunae with bland lymphocyte-like nuclei.
• Maffucci syndrome is a condition where multiple enchondromas are found in association with soft tissue and visceral hemangiomas and lymphangiomas.
• • May be associated with Paget's disease of bone, osteoporosis, or osteopeniaOsteosarcomaChondrosarcomaEwing's SarcomaChondromaOsteochondromaFibrosarcomaMalignant Fibrous HistiocytomaMalignant Tumors of the Joints and Soft TissuesMalignant Fibrous HistiocytomaMalignant Tumors of the Joints and Soft TissuesMalignant Fibrous HistiocytomaMalignant Tumors of the Joints and Soft TissuesMalignant Fibrous HistiocytomaMalignant Tumors of the Joints and Soft TissuesMalignant Fibrous HistiocytomaMalignant Tumors of the Joints and Soft TissuesMalignant Fibrous HistiocytomaMalignant Tumors of the Joints