Abstract
The following case report details the presentation of a left maxillary painless expansile lesion in a five-year-old female that was proven to be desmoplastic fibroma (DF) of the maxilla, which was treated via a conservative excision. Given the paucity of DF cases in the Maxillofacial literature, there are no formally agreed-upon guidelines for the treatment of DF, especially in the maxillary sinus. A thorough review of the literature was completed and discussed, highlighting the correlation of DF with Tuberous Sclerosis Complex (TSC) and the proposed treatment when encountered in the maxillary sinus of a pediatric patient.
Highlights
- •
Many surgical options have been suggested for maxillofacial DF, without agreed upon consensus.
- •
Maxillofacial DFs are rare tumors with fewer than 160 reported in the English literature.
- •
Although benign, this tumor can grow rapidly and be destructive, complicating treatment.
- •
Maxillofacial DFs may be a manifestation of Tuberous Sclerosis Complex (TSC).
- •
In this case we propose a conservative excision of DF in the maxillary sinus.
Desmoplastic Fibromas (DF) are benign, locally invasive myofibroblastic neoplasms of bone or connective tissue [ ]. The incidence of Desmoplastic fibroma (DF) is estimated as 0.11 % of all primary bone tumors [ ], but when the lesion occurs, the most common location is the posterior mandible [ , ]. Desmoplastic fibromas are a rare tumor, and there have been fewer than 160 reported cases of maxillofacial DF in the English literature since 1965 [ , ]. Desmoplastic fibromas located within the maxillary sinus are even less reported, and fewer than 40 DFs of the maxillary sinus have been published [ ] The affected patient population is most commonly below the age of 30 with some studies supporting a slight female predilection [ , , , ]. Some studies have suggested an association between DF and TSC [ , ], but given the rarity of the disorder, there is a paucity of data to support this association. To date, there are only a few case reports of maxillofacial DF in TSC patients [ ]. This case report will serve as a review and another case in the literature highlighting the possible association of DF and TSC.
The present report discusses a case of a 5-year-old female patient who presented to Virginia Commonwealth University Health System Department of Oral and Maxillofacial Surgery upon referral from a pediatric dentist with report of a painless left maxillary expansile swelling.
Health history was significant for TSC with a history of seizures and autism spectrum disorder. The patient’s mother reported mild bleeding during tooth brushing but otherwise denied symptoms reported by the patient. Family history was negative for TSC or any history of gnathic tumors. The patient denied pain at the time of initial evaluation, however on subsequent evaluations, the patient reported mild pain upon palpation. The patient’s initial extraoral photo is included below ( Fig. 1 ).
At the initial evaluation in October 2021, clinical evaluation revealed a roughly 2 × 2 cm expansile lesion distal to tooth #J in the left maxilla. The lesion was not tender to palpation. At that time, an incisional biopsy was scheduled under deep sedation in the operating room and the biopsy was completed in October of 2021. The specimens were sent for evaluation by an anatomic pathologist with expertise in bone and soft tissue pathology of the head and neck at the Virginia Commonwealth University Health System (VCUHS) and by Oral and Maxillofacial Pathology at Virginia Commonwealth University School of Dentistry.
The specimen sent to pathology was reported as a tan-white, translucent, firm fibromembranous tissue. Histologic interpretation of the specimen revealed a proliferation of spindle cells with evenly collagenous stroma involving the bone and surrounding tissue sampled. Several immunohistochemical stains were performed. Beta-catenin, which has been reported as positive in previously studied DFs [ , , ], only demonstrated weak cytoplasmic staining and rare nuclear staining. Focal rare SMA-positive spindle cells were identified. Pancytokeratin, SOX10, CD34, EMA, STAT6/MUC4, Desmin, MyoD1, ERG, CD31 were all negative. The final histological interpretation included a differential diagnosis of stromal-dominant fibrous dysplasia and desmoplastic fibroma of bone. Given the management differences for each lesion, additional molecular testing was completed to achieve a final diagnosis. The tumor was negative for GNAS mutation, which can be found in fibrous dysplasia, and MDM2 amplification, which can be found in low-grade osteosarcomas [ ]. The final biopsy result was suggestive of desmoplastic fibroma.
After discussion with the patient’s family regarding the results, a medical-grade computed tomography scan (CT) scan under anesthesia was ordered for surgical planning. The imaging was reviewed by musculoskeletal radiology at VCUHS and oral and maxillofacial radiology at VCU School of Dentistry. The patient was previously imaged with Cone beam computed tomography (CBCT) in the clinic, however, due to motion artifact, the imaging quality was inadequate.
CT maxillofacial with intravenous contrast revealed a lobulated soft tissue structure centered within the left maxilla which measured approximately 3.2 x 2.6 × 2.2 cm in maximal representative dimensions. The mass extended superiorly into the left maxillary sinus and to a lesser degree, laterally into the deep soft tissues of the left buccal region as well as medially into the nasal cavity and inferiorly into the oral cavity, displacing multiple unerupted teeth. Of note, posteriorly the lesion was within the posterior maxillary sinus wall abutting, but not infiltrating the left pterygoid plate. Remodeling and expansion of the surrounding bone was also appreciated ( Fig. 1 ), supporting the previous histological diagnosis of desmoplastic fibroma.
At the subsequent evaluation, there was an extensive discussion about treatment options and recommendations. We discussed at length with the family the rarity of this tumor, especially regarding patients with TSC. Due to limited evidence-based literature on the treatment of maxillary DFs in patients with TSC, we opted to treat the tumor more aggressively in areas of concern such as the skull base but to treat it more conservatively in areas that are easier to monitor to limit the need for more invasive reconstruction in the future. Given that there are no set treatment guidelines regarding maxillary sinus DF, we elected to treat it as conservatively as possible given the patient’s age and proximity to vital structures including the orbit.
We also discussed that definitive reconstruction could not be performed simultaneously given the patient’s age and that it would be wise to wait until her maxilla nearly completed growth. Written consent was obtained after a discussion of risks, benefits, and alternatives. Discussion of the use of bone morphogenic protein given the patient’s age was also discussed with the family. Virtual surgical planning was performed with 3D systems for the fabrication of cutting guides and a stereolithic model for reference during surgery ( Fig. 2 ).
