PAEDIATRIC SARCOMAS AN OVERVIEW By Dr Sonia Ike

PAEDIATRIC SARCOMAS AN OVERVIEW By: Dr Sonia Ike – SHO June 2019

What is a ‘sarcoma’? These are “malignant neoplasms of connective (mesenchymal) tissue origin” Exhibit rapid growth in a very centripetal manner Tendency to invade normal tissues which are adjacent Primary mode of spread is via the haematogenous route - lungs commonly, or other bone sites

Rhabdomyosarcom a ■ Pearls: MOST common sarcoma in young patients; rapid growth; aggressive ■ Demographic affected: Age <18 years (ERMS <5, ARMS any age) ■ How does it present? In any soft tissue site in the body, which will determine the symptoms and signs ■ Histological morphology? “spindle cells in bundles that are parallel, giant cells that are multinucleated, racquet-shaped cells” “Cross-striations within the tumour cells” i. e. rhabdomyoblasts ■ Metastasis? Lungs, bone marrow, other bones ■ Management: Multiagent chemotherapy, and subsequent surgical resection (wide margin); external beam irradiation also plays a significant role in the management and treatment

Ewing Sarcoma ■ Pearls: Small, ‘blue tumour’, round cell, ‘onion-skin periostitis’, raised ESR, leukocytosis, anaemia, raised WBCs, commonly affected sites include pelvis, distal femur, proximal tibia, femoral diaphysis, proximal humerus ■ Demographic affected: Age >5 years to young adults ■ How does it present? Constitutional symptoms including pain, and fever, large soft tissue component sometimes ■ Radiological evidence? “large, destructive lesion involving both the metaphysis and diaphysis” Lesions may be lytic purely, or conversely, display “reactive new bone formation” ■ Metastasis? Lungs, bone marrow, other bones ■ Management: Bone marrow to stage, surgical resection (wide margin), multiagent chemotherapy and adjuvant radiotherapy (limited to disease of the pelvis and spine where risks of resection are high or as an adjunct to surgery)

Osteosarcoma ■ Pearls: spindle cells that produce osteoid. Types include: conventional (intramedullary), parosteal, periosteal, highgrade and low-grade central, telangiectatic, surface, highgrade surface, multicentric, secondary (e. g. from Paget’s but this is not paediatric), postradiation osteosarcoma ■ Demographic affected: Any age (but conventional form, parosteal, periosteal are the common malignant types in younger people) ■ How does it present? Conventional – pain; parosteal – painless mass; periosteal - pain ■ Histological morphology? Conventional – poorly arranged osseous trabeculae; parosteal - regularly arranged osseous trabeculae; periosteal osseous trabeculae, chondroblastic elements ■ Metastasis? Lungs, other bones, brain ■ Management: Chemotherapy and limb salvage therapy for the above types

Neurofibrosarcoma /malignant peripheral nerve sheath tumour (MPNST) ■ Pearls: Originating from neurofibromatosis (von Recklinghausen disease) – peripheral and central forms; Café au lait spots, Lisch nodules; nonossifying fibromas; scoliosis; bowing of long-bones; occasionally de novo ■ Demographic affected: 5 -30% of patients affected with the above; or de novo ■ How does it present? Enlarging soft tissue mass and pain may herald conversion; neurological symptoms ■ Histological morphology? ”Herringbone pattern” on H&E staining ■ Metastasis? Lungs – most commonly ■ Management: Surgical resection (wide margin), adjuvant radiotherapy and/or chemotherapy; poor prognosis in children especially

Synovial sarcoma ■ Pearls: Highly malignant, high grade ■ Demographic affected: Age 15 to 40 years ■ How does it present? May be present for years/manifest as a rapidly expanding mass lesion ■ Radiological evidence? ”mineralisation within the lesion seen in >25% of cases”, irregular contours” - all seen on CTs and plain films ■ Histological morphology? Hyperchromatic, packed cells ■ Metastasis? Tumours that are larger in size tend to spread distantly i. e. greater than 5 -10 cm; lymph node spread ■ Management: Surgical resection (wide margin), adjuvant radiotherapy

Alveolar cell sarcoma ■ Pearls: Slow growing, painless, anterior thigh ■ Demographic affected: Age 15 to 35 years ■ How does it present? As above ■ Histological morphology? ”dense fibrous trabeculae, organoid or nestlike arrangement, large, round cells, vestibular nuclei with small nucleoli” Calcifications ■ Metastasis? Lungs, brain ■ Management: Surgical resection (wide margin), adjuvant radiotherapy in some selected cases, poor prognosis

Fibrosarcom a ■ Pearls: Predilection for the distal femur; extension into epiphysis and/or diaphysis; head and neck occasionally ■ Demographic affected: Tends to affect older people, BUT does occur during all decades of life ■ How does it present? Pain, swelling, paraesthesias ■ Radiological evidence? ”lytic bone destruction in a permeative pattern” ■ Histological morphology? Spindle cells, variable collagen production, ’herringbone’ pattern ■ Metastasis? Lungs –less commonly, other bones, muscle, subcutaenous tissue, lymph nodes, brain, other viscera ■ Management: Surgical resection (wide margin), adjuvant chemotherapy

Key things to remember: A paediatric history may be challenging to take Parents tend to have great insight For fractures, never forget to exclude NAIs, and the features of such Constitutional symptoms may mimic other issues MDT discussion and appropriate planning

References 1. Miller MD, Thompson SR. Miller’s Review of Orthopaedics. 7 th ed. Philadelphia, USA: Elsevier; 2016. p. 707 -746 2. Tumor Surgery. Tumor Education. Available at: http: //www. tumorsurgery. org/tumoreducation/bone-tumors/types-of-bone-tumors/osteosaroma-conventional. aspx. [Accessed 4 th June 2019].