The patient, a 45-year-old male, was admitted to the hospital complaining of "anosmia for 2 months". Past medical history, family history and social history were not significant. Apart from anosmia, he had no other symptoms or neurological dysfunction. Computed tomography (Fig. 1A-B) and MRI demonstrated an extensive mass that had not only filled the right and left side of the nasal cavity and paranasal sinuses but also eroded the skull base, causing right frontal lobe compression. The lesion was T1WI isodense, and slightly T2WI hyperintense, with irregular margins and strong uptake of Gd-DTPA (Fig. 1C-E). In addition, a mass lesion was observed in the sellar region, obscuring a clear view of a normal pituitary. The size of the sellar mass was approximately 20 × 18 × 18 mm3. The serum ACTH value was 59.6 pg/ml (reference value: 0–46 pg/ml), and the levels of other serum hormones were within normal ranges.
The decision was made to perform a single resection of the two lesions through a pure endoscopic expanded endonasal approach. The tumor and eroded middle turbinate in the right side of the nasal cavity was initially resected (Fig. 2A). Because the right mucoperiosteal flap of the nasal septum was eroded, the left mucoperiosteal flap of the nasal septum and inferior nasal meatus was obtained for skull base reconstruction (Fig. 2B). After resection of part of the tumor and the anterior wall of the sphenoid sinus, the thin seller floor was visualized. Then, the seller floor was removed, and the seller dura was cut and moved. A soft, red and white tumor (Fig. 2C) could be completely removed from the intrasellar region by curettage without cerebrospinal fluid fistula. Seller floor reconstruction in this case included dural suture with 4 − 0 thread (Fig. 2D), return of the bone of the sellar floor and the application of artificial dura mater. Neuronavigational guidance was used because of its ability to accurately determine location (Fig. 1F), helping the operator resect the tumor and the eroded ethmoid sinus and anterior cranial base (Fig. 2E-F). The fat and muscle fascia of the quadriceps were obtained from the right leg. Along with the left mucoperiosteal flap of the nasal septum and inferior nasal meatus, the harvested leg tissues were used for anterior skull base reconstruction (Fig. 2H). The postoperative course was uneventful. MRI reexamination revealed the postoperative pathological results of the gross resection. Histological examination showed a carcinosarcoma (90% of the mass was undifferentiated carcinoma with neuroendocrine characteristics, and 10% was rhabdomyosarcoma) in the nasal cavity and paranasal sinuses and a pituitary adenoma in the intrasellar zone. The immunohistochemical results (Fig. 3) from the tumor involving the nasal cavity, paranasal sinuses and anterior cranial base were CK (+), EMA (-), GFAP (-), Ki-67 (more than 95%), NSE (slightly positive), S-100 (focally positive), Syn (focally positive), P63 (-), Olig − 2 (-), CD56 (+), CgA (focally positive), Des (focally positive), CK 8/18 (+), CK - L (+), CD99 (focally positive), Vim (focally positive), Myogenin (slightly positive), and MYOD1 (focally positive). The immunohistochemical results from the sellar tumor were ACTH (-), CAM5.2 (-), ER (focally positive), FSH (focally positive), GH (-), Ki-67 (< 1% +), LH (-), PIT − 1 (+), PRL (-), SF-1 (focally positive), T - PIT (-), TSH (-), reticular fiber staining (nesting pattern), CK (-), EMA (-), GFAP (-), NSE (focally positive), S-100 (-), Syn (+), ABT (-), and Olig-2 (-). After discharge, the patient underwent chemotherapy (cisplatin and etoposide) in another hospital. Unfortunately, he died 6 months after surgery because of tumor recurrence and extensive metastasis.