Abstract
Sinonasal undifferentiated carcinoma (SNUC) is a rare tumor which is aggressive in nature, has a different clinical course in contrast to sinonasal carcinoma and poor prognosis. Here, we are reporting first case of isolated frontal SNUC which was managed by upfront surgery followed by adjuvant treatment. We want to emphasize the importance of early presentation and timely intervention in form of conservative surgery in this highly aggressive tumor.
Keywords: Frontal sinus, Sinonasal undifferentiated carcinoma, Bicoronal approach
Introduction
Sinonasal undifferentiated carcinoma (SNUC) is a rare tumor which usually seen in nasal cavity and maxillary sinus. It has different clinical course in contrast to sinonasal carcinoma and has poor prognosis. We have encountered a case of SNUC in frontal sinus which is a very rare site for SNUC to occur.
Case Report
A 47 year female presented to ENT OPD with swelling over forehead of 3 month duration. She was also complaining of swelling in the right eye. On examination she was found to have a swelling over the forehead in the brow region approximately 3 × 2 cm extending from midline to the right side. Swelling was firm, had ill defined margins all around with mild tenderness to touch. It was extending inferolaterally so as to push the eyeball outward, inferiorly and laterally. However, she did not have diplopia and visual disturbances. There was no history of nasal discharge, nasal bleeding or loss of smell sensation. Endoscopic examination of nasal cavity was within normal limits. There was no history of smoking, radiation or exposure to chemicals. She did not have co morbidities such as diabetes mellitus, hypertension etc.(Fig. 1).
Fig. 1.
(a) Preoperative(left) (b) postoperative 1 month (right)
She was advised to get routine investigations, FNAC from forehead swelling and CECT PNS done. FNAC revealed epithelial malignant neoplasm. CECT showed a heterogeneously enhancing soft tissue density epicentered in the right frontal sinus, eroding both anterior and posterior bony tables of the right frontal sinus. It was extending medially to involve the part of left side of the frontal sinus. CEMRI was done to ensure extent of intracranial extension. Fortunately, tumor was extradural, not involving frontal lobe. Considering the limited extension of tumor, decision of upfront surgery was taken by multidisciplinary tumor board. Imaging for distant metastasis was negative. (Fig. 2)
Fig. 2.
(a) axial CECT bone window showing erosion of anterior and posterior table of frontal sinus (b) axial CEMRI T1 W showing enhancing tumor (c) coronal T2W MRI (d) saggital T2W MRI.
Surgery
Patient underwent excision of tumor followed by frontal sinus obliteration.(Fig. 3).
Fig. 3.
(a)skin incision (b) subgaleal flap elevation (c) tumour delineation (d) drilling of bone with safety margin (e) removal of anterior bony table of frontal sinus with tumor (f) tumor removal from posterior wall (g) complete tumor removal done (h) fat obliteration
Surgical Steps
Bicoronal incision in the scalp skin was made few centimeters behind hair line in curvilinear fashion.
Skin flap was elevated in subgaleal plane till the supraorbital ridge bilaterally.
While raising skin flap, tumor was encountered few centimeters superior to supraorbital ridge. Galea aponeurotica (epicranial aponeurosis) was found to be involved by tumor in this region hence flap was elevated in subcutaneous plane.
Tumor was delineated all around. Soft tissue and bone cuts were made with oncological safe margin.
Growth was epicentered in the right frontal sinus, eroding the anterior table of frontal sinus, was extending medially to involve the mucosa of left frontal sinus. It was also extending inferolaterally causing erosion of roof of right orbit. However it was not involving the periorbita. There was small area of bony erosion in the posterior table of frontal sinus on the right side and growth was abutting duramater in this region, however ,it was not involving the duramater or frontal lobe.
Tumor was removed in toto along with anterior table of frontal sinus. Left over posterior table bone was drilled to ensure complete clearance of tumor followed by frontal sinus obliteration using fascia lata and fat which was taken from right side of thigh.
Histopathology & IHC
On examination of H&E stained slides on 100X, sheets of undifferentiated pleomorphic malignant epithelial cells seen. On further examination with immunohistochemistry, cells are found to have CK7 and CKAE1/AE3 positivity.(Fig. 4).
Fig. 4.
(a) sheets of undifferentiated pleomorphic malignant epithelial cells on H&E 100X (b) CK7 positivity (c) CKAE1/CKAE3 positivity
Discussion
Sinonasal Undifferentiated carcinoma was first described in 1986 by Frierson et al. based on its distinct histology, immunohistochemical profile and clinical course [1]. Incidence is as low as 0.02 per 100,000. It is thought to have a male preponderance and bimodal distribution with median age of presentation being 50 years [2, 3]. Since it is a highly aggressive malignancy, it usually presents with advanced clinical features over a short span of time due to the local invasion of surrounding structures [4]. About one third of the patients present with locoregional nodal involvement and distant metastases, particularly to the lung and bone.
To diagnose SNUC, Electron microscopy & Immunohistochemistry are required; however, simple differentiation of SNUC from other undifferentiated tumours can be done on light microscopy as well. SNUCs show reactivity for Keratin, Epithelial membrane antigen, sometimes for Neuron specific enolase and CD99 also with no reactivity for chromogranin, synaptophysin, S-100 and vimentin [1].
SNUCs are often unresectable at the time of presentation as the patients present in advanced stages owing to the locally destructive nature of the tumour. However, the disease in our case was limited to frontal sinus only; hence it was possible to remove tumour in toto. This also highlights the importance of earlier presentation and timely intervention in such an aggressive tumor. Since the complete removal of the tumour with wide margins is often not possible because of the complex anatomy of the head & neck, the treatment involves a combination of Surgery, chemotherapy & radiotherapy with the goal being control of local disease, preservation of vision and limiting significant intracranial extension [5, 6].
The prognosis associated with SNUC is poor, and death often occurs within a short span of time following the diagnosis. Improved survival results for SNUC were reported by Deutsch et al. by using aggressive multimodality approach [7] Despite the advances, the cure rate for SNUC remains low, recurrence rate is very high and many patients die of disease within months of diagnosis [8].
Funding
No funding was raised.
Declarations
Ethical Statements
All procedures performed were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Conflict of Interest
No conflict of interest.
Ethical Approval
Ethical approval was taken from institutional review board.
Informed consent
Well Informed consent was taken from patient before embarking upon surgery.
Footnotes
Publisher’s Note
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References
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