myositis ossificans ( mo ) is a rare and pathological heterotopic deposition of bone in striated muscle , tendon , ligament , fascia , and aponeurosis . generally , the two main forms are congenital ( mo progressiva ) and acquired , which is described as traumatic mo ( also referred to as mo circumscripta ) or non - traumatic mo . while the non - neoplastic , progressive ossification of soft tissues due to a congenital etiology results in early mortality from respiratory compromise , some acquired forms also result in serious morbidity due to inadequate treatment options123 . in the head and neck region , mo has involved muscles such as the temporalis , masseter , buccinator , sternocleidomastoid , trapezius , and platysma45 . the soft tissues of the myocardium , diaphragm , tongue , larynx , smooth muscles , and sphincters are spared calcification in mo . mo progressiva appears in childhood as an autosomal dominant condition with irregular penetrance where ectopic bone formation can occur at any age , but particularly occurs between birth and 10 years of age . this genetic anomaly is the most extreme manifestation of mo and consists of skeletal abnormalities , including microdactyly of the first digits , exostosis , and the absence of the two upper incisors6 . while mo can occur in either sex , the acquired forms are uncommon in children . micheli et al.7 reported that only 57 cases of pediatric traumatic mo have been identified . the most recent report of the condition in the platysma involved an adult patient who had previous radical neck dissection8 . we have found no previous report of traumatic mo of the platysma in a child . this paper presents a case of traumatic mo of the platysma in an 11-year - old female patient to illustrate the associated management challenges in a resource - constrained setting . an 11-year - old female patient was admitted to the military hospital ( lagos , nigeria ) through the casualty department on referral from a boarding school on account of dysphagia to solids and very painful submandibular swelling of 3 days duration . she denied a history of trauma to the area and the symptoms were not affected by the smell or sight of food . there was no obvious dental cause of the swelling and wharton 's duct was patent . due to the severity of the symptoms , she was hospitalized on the presumptive diagnosis of acute sialedenitis and started on intravenous ceftriaxone 40 mg / kg body weight every 12 hours for 3 days and intramuscular acetaminophen 480 mg every 8 hours for 3 days . consultation with the otorhinolaryngologist found no ear , nose , or throat causes for her dysphagia . on the third day of admission , the dysphagia and pain had subsided , allowing for better clinical examination that revealed a mobile , irregularly - shaped , tender left submandibular mass.(fig . 1 ) bimanual palpation did not suggest the presence of stones in the submandibular gland or ducts . plain posterior - anterior radiograph and occlusal radiograph of the lower jaw showed no abnormalities . ultrasonography of the left submandibular region revealed two irregular , well circumscribed hypoechoic lobulated masses measuring 13.2 mm by 10 mm and 15.2 mm by 14.4 mm in dimension , with slight posterior enhancement but no calcification.(fig . 2 ) the presumptive diagnosis by the sonologist was malignant tumor of the submandibular gland with the recommendation of further imaging studies , followed by excision of the mass for histopathologic examination . further imaging , such as computed tomography ( ct ) and magnetic resonance imaging ( mri ) , was not done as they were not affordable for the parent . by the tenth day of consultation , there was very little resolution of the mass , which was mobile but diffuse , and thus the initial presumptive diagnoses were all ruled out . a probable mucoepidermoid carcinoma of the submandibular gland was suspected and the parent was advised to allow for excisional biopsy of the gland . after routine pre - surgical work - up for general anesthesia , a left submandibular incision was made on the skin . after reflecting the investing layer of the deep cervical fascia , the platysma was felt to be gritty on palpation and to the surgical knife , and a portion was excised for histopathology . further palpation in the region yielded no other masses , so the submandibular gland was left undisturbed . the tissue histology revealed necrotic hemorrhagic skeletal muscle fibers with mature lipocytes , focal dystrophic calcification , and acellular debris.(fig . 3 ) the final diagnosis was traumatic mo of the platysma . when presented with the diagnosis , the patient admitted to traumatic injury to the submandibular region due to bullying by seniors from her boarding house , but the parents chose to transfer the child to another school and postoperative review after 6 months showed complete resolution of the symptoms and good wound healing . schajowicz10 stated that while non - traumatic mo occurs in association with neuromuscular diseases , tetanus , poliomyelitis , and burns , some causes could be idiopathic . traumatic mo occurs more commonly in males than in females , possibly due to the relatively higher exposure of males to trauma . about 80% of cases reportedly arise in the large muscles of the extremities ( e.g. , quadriceps muscle or brachialis muscle)11 , and occurrence in the head and neck region is uncommon . although some authors deny such an association , a history of prior trauma , often associated with sports injuries , is reported in around 60% to 75% of patients10 . sodl et al.14 reported that fraternity hazing and other forms of school bullying could cause traumatic mo . apart from sport - related injuries , minor to severe local trauma , such as the striking of the cheeks , fractures of the jaws , and falling off a horse , have been reported to be causes of traumatic mo in the muscles of mastication4 . this case report is possibly the second report of involvement of the platysma and the first case of traumatic mo of the platysma due to bullying reported in the literature . the case of tmo described by shugar et al.8 was attributed to surgical trauma to the platysma muscle during radical neck dissection . worldwide , the magnitude of the effects of hazing and bullying in schools may never be known . our patient only volunteered the traumatic cause of her injuries when presented with the histologic diagnosis . refusal to volunteer a history of bullying could be due to the fear of retribution , shame , or a desire to protect the perpetrator(s ) . there is a need for collaborative surveillance involving parents , school teachers , and physicians to detect and eliminate the dangerous practice of hazing and bullying from schools . mo often starts as a non - specific painful soft tissue mass that could be mistaken for an infection or a soft tissue tumour15 . in non - traumatic mo , the predisposing illness is fairly obvious , while in traumatic mo , early cases could still contain hematomas detectable on diagnostic ultrasound . the elimination of a dental etiology and the initial denial of trauma made salivary gland infection , stones , and tumors high on the differential diagnoses . localization of the submandibular swelling after resolution of the acute phase and further clinical examination showing slight left submandibular swelling ( fig . sialolithiasis could be confused with traumatic mo , even when no stones are palpable in the gland or duct , and remained a possibility until surgery . traumatic mo of the platysma was not considered due to its rarity and the denial of a history of trauma to that part of the body . imaging modalities such as plain radiographs , ultrasound , scintigraphy , ct and mri have been extensively used to elucidate the diagnosis and monitor the treatment of traumatic mo . according to reports , plain radiography shows a soft tissue swelling and faint peripheral calcification in the early stages of traumatic mo ( less than 2 - 4 weeks ) followed by well - defined calcification in the middle stages ( 5 - 24 weeks ) that may be associated with coarser , central calcification . the fully matured traumatic mo ( > 6 months ) is densely calcified and usually lies parallel to the long axis of the adjacent bone1718 . plain radiographs of the submandibular region in our patient showed no anomalies , probably because the lesion was located in the platysma , which is a thin muscle , as well as the lesion 's early stage of development 4 weeks after the injury . wang et al.16 stated that ultrasonography of traumatic mo reveals a hypoechoic mass with a central reflective core with sheet - like ( lamellar ) hyper - reflectivity at the periphery of the mass in the early lesion , more reflective areas in the intermediate lesion , and diffuse reflective areas in the late ( mature ) lesion . consists of two irregular , hypoechogenic masses , resulting in the inaccurate suspicion of a malignant tumor of the submandibular gland . it is possible that a central reflective core of calcification was identifiable by wang et al.16 because they studied larger muscle masses such as the quadriceps , and this characteristic may not be identifiable in the thin platysma muscle . in addition , the sensitivity of the ultrasound equipment used could also affect the ability to demonstrate this feature in early cases of mo . the importance of modern equipment in diagnosis and treatment can not be over - emphasized ; however , several factors limit their accessibility in resource - poor countries such as nigeria . using scintigraphy , wang et al.16 reported that early traumatic mo shows mildly increased uptake to marked soft - tissue accumulation of tracer , while on ct scan , it shows an enlarged muscle group with normal attenuation with or without faint calcification within the lesion . scintigraphy of the intermediate lesions shows a progressive decrease in radiotracer uptake while the ct scan shows zonal phenomenon characterized by a rim of calcification with varying thickness at the periphery and a central area with the same attenuation as normal muscle . in the late lesion , scintigraphy shows mild or normal uptake while the ct scan shows a heavily calcified lesion16 . though not routine , mri could compliment plain radiographs by better defining hard and soft tissue structures . our hospital had no facilities for scintigraphy , ct , and mri , and the parent could not afford the cost in private hospitals . it is noteworthy that traumatic mo has no pathognomonic appearance on imaging and the diagnosis depends on an adequate and reliable history , followed by appropriate clinical examination . chuah et al.19 reported that the erythrocyte sedimentation rate and alkaline phosphatase could be elevated in the acute phase of traumatic mo . while these tests were not carried out in this patient , they are non - specific with wide variations based on age and sex , especially the alkaline phosphatase levels found in growing children20 such as this 11-year - old girl . the early lesion shows immature osteoblasts and proliferating fibroblasts , as described by micheli et al.7 . in the intermediate lesion , dystrophic calcification and necrotic haemorrhagic skeletal muscle could be found , as seen in our patient.(fig . 3 ) in the late stage , lamellar bone delimited by osteoblasts can be seen5 . shugar et al.8 suggested that because of the risk of recurrence , the abnormal bone formed in the platysma should be removed only if there are significant associated symptoms . such surgery should be delayed for 6 to 12 months following the traumatic episode to allow for maturation because lesional immaturity could be a contributory factor to recurrence . hanquinet et al.21 presented the cases of two children with traumatic mo of the arm . in their opinion , while the lesion could spontaneously resolve , surgery could be done to remove some tissue for diagnosis if typical calcification is not observed in the mature lesion . in the 16-year - old patient studied by russo et al.22 , the traumatic mo was associated with severe pain , although there was no radiologic evidence of calcification . these authors believe that waiting for complete maturation of the lesion may not be necessary in the presence of severe symptoms . our patient had surgical excision of a portion of the involved platysma muscle with complete resolution of the symptoms within 6 months . conservative measures such as rest , analgesics , physical therapy , and extracorporeal shock wave therapy have been satisfactorily used in other non - facial body parts1923 . it is possible that following the diagnosis of traumatic mo , surgery can be delayed if symptoms are not severe . extensive excision of the early lesion is not indicated especially as clear lesional boundaries are often not discernible . given the intra - operative findings of a gritty nature of the platysma in our patient , the minimal tissue removed did not affect the resolution of symptoms . in early cases of traumatic mo , excision of the entire muscle is potentially not necessary .