ISSN: 2572-4193 Elkhatib et al. J Otolaryngol Rhinol 2018, 4:039 DOI: 10.23937/2572-4193.1510039 Volume 4 | Issue 1 Journal of Open Access Otolaryngology and Rhinology CASE REPORT Chondroblastoma of Ventral Skull Base: First Report of a Case Ahmad Elkhatib1, Paul Wakely Jr2, Luciano M Prevedello3, Ralph Abi Hachem1, Andre Beer-Furlan4, Daniel M Prevedello1,4 and Ricardo Carrau1,4* 1Department of Otolaryngology - Head and Neck Surgery, The Ohio State University Wexner Medical Center, Columbus, USA 2 Department of Pathology, The Ohio State University Wexner Medical Center, Columbus, USA Check for 3Department of Radiology, The Ohio State University Wexner Medical Center, Columbus, USA updates 4Department of Neurological Surgery, The Ohio State University Wexner Medical Center, Columbus, USA *Corresponding author: Ricardo L Carrau, M.D, F.A.C.S, Professor, Department of Otolaryngology-Head & Neck Surgery, Di- rector of the Comprehensive Skull Base Surgery Program, The Ohio State University Wexner Medical Center, Starling Loving Hall - Room B221, 320 West 10th Avenue, Columbus, OH 43210, USA, Tel: 614-685-6778, E-mail: [email protected] Abstract Introduction Objective: Report of the first case of chondroblastoma in- Chondroblastoma is a rare neoplasm of the bone volving the sinonasal cavity and ventral skull base, offering constituting approximately 1% of all primary bone tu- a description of the puzzling diagnostic process followed mors. It is more common in men in their second or third by its management. We describe the main radiologic and histologic characteristics of chondroblastoma and compare decade of life and usually affects long bones. The skull them to those of frequently mistaken differential diagnoses. base undergoes a mixed membranous and endochon- dral ossification; thus, it is rarely affected by chondro- Design: Case report of a 19-years-old male patient with fi- nal diagnosis of chondroblastoma. blastomas. Nonetheless, they most commonly affect the temporal bone [1,2]. This report presents the first Results: A 19-years-old male patient presented with visu- al deterioration. Imaging revealed an expansile mass with case of a ventral skull base chondroblastoma. an epicenter in the planum sphenoidale extending both into the sphenoid sinus and intracranially. The patient was Case Report managed with partial resection via endoscopic endonasal For a period of two years, a 19-years-old healthy, Af- approach resulting in rapid recovery of vision. rican American male noticed progressive blurriness of Conclusion: Chondroblastoma of the skull base is an ex- his left eye with continual periods of aggravation associ- ceedingly rare tumor with varying prognosis. It is frequently ated with a pounding headache that would abate spon- confused with other bone tumors, such as chondrosarcoma and giant cell tumor. Meticulous radiological and histologi- taneously after one or two hours. However, the patient cal review with high level of expertise is crucial in the diag- did not seek medical attention until he suffered a motor nostic process. Complete resection is the mainstay treat- vehicle accident associated with loss of consciousness. ment; however, lesions of the skull base should always be The patient reported a history of migraine headaches tempered with potential complications. since childhood; however, he denied double vision, Keywords nosebleeds, nasal obstruction, or memory lapses and Chondroblastoma, Endoscopy, Skull base, Bone tumor his family denied any evidence of personality changes (before or after the accident). A brain and cervical spine computed tomography (CT) scans (Figure 1) showed a large expansile mass cen- tered in the planum sphenoidale extending both intra- Citation: Elkhatib A, Wakely Jr P, Prevedello LM, Hachem RA, Beer-Furlan A, et al. (2018) Chondroblas- toma of Ventral Skull Base: First Report of a Case. J Otolaryngol Rhinol 4:039. doi.org/10.23937/2572- 4193.1510039 Accepted: May 23, 2018: Published: May 25, 2018 Copyright: © 2018 Elkhatib A, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduc- tion in any medium, provided the original author and source are credited. Elkhatib et al. J Otolaryngol Rhinol 2018, 4:039 • Page 1 of 5 • DOI: 10.23937/2572-4193.1510039 ISSN: 2572-4193 Figure 1: Preoperative CT scan A) Coronal; B) Sagittal (see text). Figure 2: Preoperative MRI A) T1 sagittal MRI; B) T2 coronal MRI (see text). cranially and into the sphenoid sinus with involvement scopic endonasal approach (EEA). Intraoperative find- of the left anterior clinoid process. The outer margins ings included a very large fibro-osseous lesion invading of the mass demonstrated cortical bone that appeared the sphenoid sinus, involving the sella and suprasellar predominantly intact except in a few areas of disconti- space, and extending into the anterior skull base overly- nuity. The mass measured 4.9 × 3.0 × 4.2 cm and had a ing the planum sphenoidale. In the context of a benign soft tissue density center with Hounsfield Units varying lesion, a subtotal extradural resection was done decom- from 8 to 115 (average of 55) as well as several areas of pressing 270° of the left optic nerve canal and avoiding amorphous calcifications peripherally. a CSF leak (Figure 3). The skull base defect was recon- MRI showed that the central component of the le- structed using a right pedicled nasoseptal flap, which sion was isointense to hypointense on T1-weighted served to reline and protect the left optic nerve and in- images relative to gray matter and heterogeneous on ternal carotid artery. T2-weighted images. There were areas of extremely The patient was discharged with no complaints one low T2 signal intermixed with cystic-appearing areas. day after surgery already noticing visual improvement. Following intravenous administration of gadolinium, He followed an uneventful postoperative course and the lesion demonstrated heterogeneous but predomi- his left eye vision regained normal function within two nantly avid enhancement. The mass extended upwards weeks. The patient returned to his daily activity and into the intracranial fossa with mild displacement of the continued doing well at 2 months of postoperative fol- inferior portion of the left frontal lobe. No significant low-up. After discussion of further treatment alterna- signal abnormality was noted in the adjacent brain pa- tives, the patient agreed to follow the residual tumor renchyma (Figure 2). with imaging and monitor his vision with periodic neu- A preliminary diagnosis of an osseous lesion with a ro-ophthalmologic examinations. high suspicion for an ossifying fibroma was made, and Histopathology the patient was subsequently referred to us for further management. This included a subtotal resection of the The specimen consisted of multiple bony tissue frag- tumor with left optic nerve decompression via endo- ments that measured 4.5 cm in greatest dimension. Elkhatib et al. J Otolaryngol Rhinol 2018, 4:039 • Page 2 of 5 • DOI: 10.23937/2572-4193.1510039 ISSN: 2572-4193 Figure 3: Post-operative CT scan showing resection of the center of the lesion with overall preservation of the peripheral osseous rim A) Sagittal; B) Coronal. Figure 4: A) A solid sheet of mononuclear cells displays uniform cells with ovoid and reniform nuclei, discrete cells borders, occasional giant cells, and minimal matrix. H&E stain, x40; B) A large amount of extracellular stromal matrix is present in the upper half of this image causing a wide separation of cells. The lower half imitates the cells seen in figure 1A. H&E stain. x20. Light microscopic examination showed a solid prolifera- fibromas and aneurysmal bone cysts, while malignant tion of polygonal cells infiltrating among bone trabecu- lesions include chondrosarcoma and osteosarcoma [2]. lae. Proliferating cells had uniform rounded, ovoid and Chondroblastomas can be confused with chondrosarco- reniform hypochromic nuclei, evenly dispersed nuclear ma when there is an excessive chondroid matrix with hy- chromatin with occasional nuclear grooves but lacking percellularity, while ossification of the matrix may mimic nucleoli, a moderate amount of cytoplasm, and sharp osteoblastoma. Sinonasal ossifying fibromas typically cell borders. Mitotic figures were conspicuously infre- present as a lesion with a fibrous center and a thick pe- quent, and necrosis was absent. Eosinophilic stromal ripheral osseous rim. Intermediate to low T1 signal along matrix varied among tissue fragments with some being with mixed T2 signal composed of low signal intensity ar- almost completely cellular (Figure 4A) while other frag- eas (calcification or ossification) and high signal intensity ments contained an excessive amount of hyalinized ma- areas (fibrous tissue) are commonly described. Areas of trix (Figure 4B). Osteoclastic giant cells were scattered ossification tend to increase in size with patient’s age in throughout the tissue. Immunostain results showed ossifying fibromas [3]. Ossifying fibromas may be indis- rare S-100 staining and diffuse positivity with vimentin. tinguishable from sinonasal fibrous dysplasia, particularly when fibrous areas are more prominent, although the Discussion classic ground-glass appearance centrally would favor Chondroblastomas are rare benign neoplasms af- the latter. Another differentiating feature is that ossifying fecting any bone with endochondral ossification. Most fibromas are typically monostotic whereas