What questions would you like to ask? HPI 22 yo previously healthy F comes to the clinic complaining of right shoulder pain that has gotten progressively worse over the past 6 weeks. What questions would you like to ask?

HPI + R shoulder pain, worse with movement. + R shoulder swelling. +intermittent low grade fevers. Recently noticed a bump over the shoulder. - history of recent falls or trauma to the shoulder Denies pain/discomfort anywhere else

Differential Diagnosis? PMH: asthma PSH: appendectomy Family Hx: none Social: Graduate student. Social drinker. Denies smoking and illicits. Sexually active with her boyfriend. Meds: rescue albuterol Allergies: pollen, dust Differential Diagnosis?

Differential Diagnosis Rotator cuff tear Sub acromial bursitis Sub acromial impingement Osteomyelitis Soft tissue/bone tumor

PE Vitals: AVSS CV, Pulm, Abd: WNL Musc: swollen R shoulder without erythema. No warmth to touch. Tender to palpation over proximal arm/shoulder. Difficult to assess ROM secondary to pain. Neurovascularly intact distal R shoulder. Labs: CBC, BMP: normal ESR: 5 Alkaline phosphatase:260

XRAY

XRAY

MRI: Coronal FAST STIR

Histology

Histology

Histology

Osteosarcoma Multiple subtypes (intramedullary, parosteal, periosteal, telangiectatic) Intramedullary osteosarcoma is the most common primary sarcoma of bone usually occurs in children and young adults with bimodal distribution of occurrence majority occur in the second decade of life second peak in occurrence is in elderly patients with Paget's disease most common site is the distal femur and proximal tibia  other sites include proximal humerus, proximal femur, and pelvis Radiographs: classic “sun burst” appearance Abnormal Labs: Elevated alkaline phosphatase may be 2-3x’s normal value Orthobullets.com/pathology Miller’s review of orthopaedics

Characteristic Features blastic and destructive lesion  sun-burst or hair on end pattern of matrix mineralization periosteal reaction (Codman's triangle)

Histology tumor cells show significant atypia, and produce "lacey" osteoid  stroma cells show malignant characteristics with atypia, high nuclear to cytoplasmic ratio, and abnormal mitotic figures   Giant cells may be present in giant cell rich osteosarcoma often confused with giant cell tumor of bone

Prognosis 76% long-term survival with modern treatment poor prognostic factors : advanced stage of disease (most predictive of survival) response to chemotherapy (as judged by percent tumor necrosis of resected specimen) tumor site and size expression of P-glycoprotein high serum alkaline phosphatase  high lactic dehydrogenase vascular involvement surgical margins Orthobullets.com/pathology Miller’s review of orthopaedics