extra-osseous non neoplastic growth of new boneMisnomerHeterotopic ossificationnot always inflammatorywithin extra-skeletal soft tissues – mainly inconnective tissue than muscle
Ectopic Calcification ?!!Deposition of radio denseCalcium PhosphateDifference in mineral phaseNo true bone matrix is formedEg:- Hyper/Hypoparathyroidism,Renal failure,Following TB,Calcific Supraspinatus Tendinopathy,Scleroderma,Dermatomyositis
Without known injury:-Nondocumented trauma,Repeated small mechanical injuries(blunt traumain horse riders)Nonmechanical injuries caused by ischemia orinflammation.Increased risk in patients with Diffuse IdiopathicSkeletal Hyperostosis (DISH) and Paget’sDisease
PathophysiologyBMP stimulate primitive stem cells in soft tissuesto form osteoblastsOrganization of HaematomaFibroblastic hypoplasiaOsteoid formation
Radiographic evidence in 6-8 weeks The lesion begins to calcify at the periphery andworks toward the center (Reverse inOsteosarcoma)
Histopath- 4 distinct zones:the central undifferentiated zone- mitoticallyactivethe surrounding zone of immature osteoidformation – less activezone with new bone – osteoblast & fibroustissue with trabecular organizationPeripheral zone of fibrous tissueAt least 10 days are required following onsetof symptoms for these zones to becomeapparent.
most commonly in the second and third decadeAreas commonly affected - elbow, thigh, buttocks,shoulder and calf ., erector spinae, pectoralismuscles(Quadriceps and brachialis - most affected.)Majority –asymptomatic; may cause pain/ loss ofROM
presents as a rapid enlargement and significantpain one to two weeks after injury.Swelling and warmth at the siteHypercalcemia- contributing factorIncreased ESR and serum alkaline phosphatase.
TreatmentWatchful inactivityRest and gentle stretching.Surgery if persistent pain – excised in toto inmature casesRisk of recurrence +If left alone, the mass will shrink in size
Treatmentshould not continue to play sports or use theaffected muscle.Avoid Heat and massage.Reinjury to the same area, returning to activity tooearly, or initial passive forceful stretching canlengthen recovery.Prophylaxis: NSAIDS(Indomethacin), low doseradiation
Heterotopic Ossification OsteosarcomaSite: Diaphysis MetaphysisPeripheral rimming Ossification center(can mimic necrotic tr) to peripheryImprovement in pain over Pain worsens with time andrest timeBiopsy:Zone phenomenon Undiff tissue- viable musclefibres similar to central intact cortexzone
Myositis Ossificans Progressiva /Fibrodysplasia OssificansProgressivarare autosomal dominant disorderskeletal malformation and progressive, disablingheterotopic osteogenesis.fibrosing and ossification of muscle, tendon andligaments of multiple sites often in the upperextremities and back that is disabling andultimately fatal
Nine-year-old Mexican girl with FibrodysplasiaOssificans Progressiva (FOP).
Chromosome 2q23-24Heterozygous mutation (617G®R206H) in theglycine-serine (GS) domain of theActivin A receptor type I (ACVR1) gene, a bonemorphogenic protein (BMP) type I receptorIncidence 1in 2 millionAge: Average 5 yrs (Fetus-25 yrs)Their offspring have a 50% probability ofinheriting the condition.
painful lumps and stiffness in the adjoining joint. Lumps decrease in a few weeks, but jointmobility reduction persists.Exacerbating factors for ossifications at new sitesminor trauma, venipuncture,biopsy of lumps, IM injections,dental treatments, and excision of masses.
Most common sites:- sternocleidomastoid,paraspinal muscles, the masticatory muscles,shoulder and pelvic girdle muscles.Spared are the abdominal muscles, extraocularmuscles,muscles of facial expression, diaphragm,larynx and tongue muscles.Ossification progresses from proximal to distaland cranial to caudal.
C/FDigits: Short hallux in valgus with synostosisshort thumbs , ClinodactylyFibrous Tissues: Swelling in aponeuroses,fasciae, and tendons- ossification in musclesand fibrous tissues,most prominent in the neck dorsal trunk andproximal extremities (The sternocleidomastoidmuscle is commonly affected.)Kyphoscoliosis: Restricted shoulder andpelvic girdle movements
LabHemogram, ESR, S.Ca, P:- WNLECG findings may be abnormalspirometry :-restrictive pattern, reflective of chestwall involvement.
Plain radiography of FOPShort metacarpals and metatarsalsPhalangeal synostosis (eg, monophalangeal greattoe)Vertebral fusions, vertebral anomalies (i.e., smallbodies), pedicle thickeningThick, short femoral neckVariations in bone maturation sequenceIncreased incidence of enchondromas
TreatmentOnce diagnosis is established, usually clinically,any surgical biopsy is contraindicated in FOP.No established medical therapy exists. Pain medications supportive measures -gentle occupational and/orphysical therapy.
Prevention is better!!avoid falling or getting bruisesavoid IM injections since these cancause bone to grow.Never stretch their joints outside oftheir normal ROM.Flare-ups can occur spontaneously,even perfect preventive care cannotguarantee the absence of bone growths.
The mainstay of diagnosis is bilateralgreat toe anomaly present from birth,reported in 79 to 100% of patientsmicrodactyly of both halluces due to asingle phalanx in valgus positionThe finding of congenital hallux valgusmust raise the possibility of FOP so thatmanagement should be early andadequate.