Rhabdomyosarcoma is a high-grade malignant neoplasm with skeletal muscle differentiation; a common soft tissue sarcoma in children but considered one of the rarest in adults. Rhabdomyosarcoma (RMS) is a primitive malignant soft tissue tumor arising from premature mesenchymal cells. The current study presents a rare case of embryonal rhabdomyosarcoma in the nasal cavity of an adult patient. Rhabdomyosarcoma is a high-grade malignancy, known for its aggressive nature and its ability to metastasize, leading to a poor prognosis. It typically grows locally and can spread to surrounding tissues and regional lymph nodes. Due to its potential for distant metastasis, early detection and treatment are crucial.

Case Presentation

A 19-year-old male patient presented to ENT OPD with complaints of noisy breathing for the past 10 days and proptosis for the last 15 days. Nasal obstruction had been present for approximately two months, and there was a history of a single episode of epistaxis two months ago.

On examination, there was foul-smelling discharge from both nasal cavities. Examination of the oropharynx revealed a bulge in the soft palate, which was significantly occluding the airway. Neck examination was normal.

HRCTParanasal Sinuses showed a large, well-defined heterogeneously enhancing soft tissue mass of size 6.3 × 5.8 × 8.5 cm in the nasal cavity, extending into thenasopharynx,ethmoidal air cell, and oropharynx. The mass exhibited intracranial and intra-orbital extension with multiple vascular channels.  There was Destruction of adjacent bony structures, including the lamina papyracea, cribriform plateandsphenoidal air cells.

The mass was seen Encroaching on the oropharynx and nasopharynx causing complete occlusion of the nasopharynxand partial occlusion of the oropharynx.

Figure 1: Case of Nasal Rhabdomyosarcoma

Intra-cranial invasion with frontal sinus erosionand displacement of orbital structures was seen MRI (Neck) Findings showed a Heterogeneously enhancing T2/FLAIR lesio, measuring 6.5 × 6.3 × 10.5 cm, involving the nasopharynx, oropharynx, bilateral nasal cavity, ethmoids, and frontal sinus.  Bilateral orbital invasion, with displacement of the left globe and infiltration into the medial rectus and optic nerve was seen. There was  Intracranial extension with effects on the right basifrontal region causing buckling of underlying grey matter along with Bony erosion of the cribriform plate, lamina papyrace, and frontal bone.

Gross Examination showed Multiple grey-brown to tan-brown soft tissue fragments, measuring1.8 cm with Microscopic Examination showing Presence of benign respiratory and metaplastic squamous epithelium.

• Nodular aggregates and sheets of tumor cellsexhibitinghigh nuclear-cytoplasmic (NC) ratio, hyperchromatic round nuclei, and conspicuous nucleoli and Moderate eosinophilic cytoplasm with atypical mitotic figures Loose myxoid stroma with lymphoplasmacytic infiltrate.

• Areas of necrosis with vascular congestion.

Immunohistochemistry (IHC) Findings were as follows:

• Findings suggested: Embryonal Rhabdomyosarcoma.  

• Following diagnosis, patient was started on Chemoradiotherapy (VAC Regime with 66Gy RT).

RMS is the most common malignant neoplasm of the soft tissues, which is predominantly found in children with extreme rarity in adults. It is believed to recapitulate the early developmental form of skeletal muscle cells (1) It has been observed that ERMS mainly affects the head and neck area of the pediatric population while occurring most frequently in the extremities of adults. Adult ERMS of the nasal chambers represent only 10%–15% of head and neck cases (2)

Even though several studies reported the presence of nasal obstruction and swelling of the affected area in ERMS patients, specific presentation and symptoms regarding ERMS of the nasal cavity is not well described.

ERMS of the nasal cavity is an exceedingly rare type of malignant tumor in adults that presents a diagnostic and management challenge, with immunohistochemistry being the only definitive diagnostic tool. Furthermore, due to their poor prognosis and clinical outcome compared to the pediatric population, adult ERMS might require particular treatment adaptation.

1. Patil, G., et al. “Embryonal rhabdomyosarcoma occurring on mandibular gingiva in an adult.” Journal of Clinical and Diagnostic Research, vol. 7, no. 9, 2013, pp. 2088-2089. https://pubmed.ncbi.nlm.nih.gov/24179953/. 

2. Hamou, M., et al. “Adult embryonal rhabdomyosarcoma of the nose and paranasal sinuses misdiagnosed as an orbital cellulitis: a case report.” PAMJ Clinical Medicine, vol. 5, no. 3, 2021, pp. 1–7. https://www.clinical-medicine.panafrican-med-journal.com/ content/ article/5/3/full/.