Volume : 4
Issue : 4
Online ISSN : 2394-6792
Print ISSN : 2394-6784
Article First Page : 658
Article End Page : 663
Introduction: Rhabdomyosarcoma (RMS) is a rare tumor, with an annual incidence of 4.3 cases per million children. The orbit is the primary site in approximately 10% of these tumors. RMS is the most common malignant orbital tumor of childhood. It usually appears in the first decade of life. The mean age at diagnosis is 8 years. Boys are affected more than girls. Orbital RMS usually presents as a space occupying lesion in the orbit. The tumor has predilection for the superior nasal quadrant of the orbit. The common histological types include embryonal(60%), alveolar(20%) and pleomorphic (20%).The most common sites being sinuses, head and neck regions, genitourinary tract. CT and MR imaging are important in the evaluation of this tumor. The diagnosis is most rapidly and reliably confirmed by immunohistochemical(IHC) by demonstration of one or more muscle antigens. At times, the myxoid stroma and polypoid configuration of some RMS might be mistaken for nasal polyps or myxoma. Treatment usually consists of a combination of chemotherapy and radiation therapy following surgical excision.
Case Report: In our study, a 1 year old male patient presented to a local ophthalmologist with complain of painless swelling of left orbit. CT scan revealed picture suggestive of venolymphatic malformation (March 17,2016) .Thereby, he was referred to a well known health care centre where MRI was advised which revealed a picture suggestive of rhabdomyosarcoma with differential diagnosis of plexiform neurofibroma. Total excision of the orbital mass was done at the same centre and a diagnosis of orbital myxoma/ angiomyxoma was given in HPE (April 29,2016). After about 2 months following the excision biopsy, patient’s parents noticed swelling of the same orbit which was aggresive. He was brought to the pediatric surgery department of AMCH and re-biopsied. One specimen was sent to our department and the other to a private centre. The report from the private laboratory suggested myxoma. The report from our college was given as Embryonal rhamdomyosarcoma and further subjected to immunohistochemistry (IHC). IHC was positive for desmin, myogenin and vimentin. Complete haemogram, ESR were within normal limits.
Conclusion: In our case, the patient deteriorated within a very short span of 8-9 months due to misdiagnosis owing to its histological similarity to myxoma. The histopathologist reporting the case previously missed to observe the huge size of the tumour. The facility of IHC was also not utilized. Thus, histopathology along with IHC should be used as an ancillary test in cases as confusing as ours, thereby saving patients valuable time.
Keywords: Embryonal rhamdomyosarcoma, IHC, Myxoma, Desmin, Myogenin, Tumor, Orbit