Embryonal rhabdomyosarcoma in the maxillary sinus with orbital involvement in a pediatric patient: Case report

Abstract

This report presents a case of embryonal rhabdomyosarcoma (eRMS) located in the left maxillary sinus and invading the orbital cavity in a ten-year-old male patient who was treated at a referral hospital. The images provided from the computed tomography showed a heterogeneous mass with soft-tissue density, occupying part of the left half of the face inside the maxillary sinus, and infiltrating and destroying the bone structure of the maxillary sinus, left orbit, ethmoidal cells, nasal cavity, and sphenoid sinus. An analysis of the histological sections revealed an undifferentiated malignant neoplasm infiltrating the skeletal muscle tissue. The immunohistochemical analysis was positive for the antigens: MyoD1, myogenin, desmin, and Ki67 (100% positivity in neoplastic cells), allowing the identification of the tumour as an eRMS. The treatment protocol included initial chemotherapy followed by radiotherapy and finally surgery. The total time of the treatment was nine months, and in 18-mo of follow-up period did not show no local recurrences and a lack of visual impairment.

Keywords: Chemotherapy; Embryonal rhabdomyosarcoma; Maxillary sinus; Oncology; Pediatrics.

Figure 1

Initial clinical features of the lesion showing a reddish painful firm mass on left side of face with rapid evolution (25 d). This lesion was causing left visual impairment with notorious swelling on facial skin with absence of other obstructive symptoms.

Figure 2

Computed tomography scan of the paranasal sinuses. On coronal view, a diffuse hypodense mass was dislocating lateral wall of left sinus and compressing the inferior border of left orbital structure with tumor invasion. On axial plan, tumor mass was filling the left sinus and a dislocated nasal septum was evident.

Figure 3

The microscopic slide showed an undifferentiated malignancy with hyperchromatic rounded cells with scarce and eosinophilic cytoplasma infiltrating the skeletal muscle tissue (hematoxylin-eosin, 40 ×).

Figure 4

An immunohistochemical analysis was performed on a biopsied tumour fragment from the left maxillary sinus. A: Immunohistochemical analysis showed positiveness to anti-Desmin antibody with dual cytoplasmatic and nuclear staining; B: The same pattern was observed against anti-Ki67 (B) showing intense positiveness and high rate of cell proliferation; C and D: Anti-myogenin and MYO-D1 were positively found on nuclear staining leading to RMS lineage supposition.

Figure 5

Monitoring of the patient after the period of 2.5 mo of chemotherapy and after completion of treatment (18 mo). A: Monitoring of the patient after the period of 2.5 mo of chemotherapy; B: Monitoring of the patient after completion of treatment (18 mo).