Maxillary Sinus Myxofibrosarcoma Mimicking Nodular Fasciitis: A Rare Case Report

Abstract

Myxofibrosarcoma (MFS) is a fibroblastic soft tissue sarcoma that is extremely rare in the maxillofacial region. Due to its non-specific clinicoradiographic findings and challenging histopathological features, the diagnosis is difficult. Here, we present a case of MFS which was first diagnosed as nodular fasciitis. The initial examination of the incisional biopsy showed a benign-appearing proliferation of fibroblasts without features of malignancy. The patient returned with recurrence four months after surgical excision of the primary lesion. The second histologic study revealed a high-grade spindle cell sarcoma with myxoid features most compatible with MFS. Definitive diagnosis of MFS was confirmed by these histopathologic features and supportive immunohistochemical stains. Unfortunately, the patient died of disease 3 months later.

Introduction

Nodular fasciitis (NF) is a benign, reactive proliferation of fibroblasts originating from the deep fascia extending to the subcutaneous tissue. NF is rare in the head and neck but the maxillofacial region is the most frequently involved site [1]. Less common areas are the forehead, scalp and skull, post-auricular region, chin, and neck [2].

Myxofibrosarcoma (MFS) is a fibroblastic soft tissue sarcoma that affects a broad age range, from teenage to adults, with peak occurrence in the seventh decade. The extremities are the most commonly affected. The maxillofacial is rarely affected, but the most commonly involved sites are hypopharynx, sinuses, and parotid glands [3]. MFS is a slow-growing mass with a high rate of recurrence; however, metastasis is uncommon. The diagnosis is challenging due to a lack of specific clincoradiographic features and histopathologic findings that overlap with numerous entities [4].

While the presentation of both of these lesions is unique in the maxillofacial region, the present case contains the diagnostic and treatment plan of a challenging case of MFS which was first diagnosed as benign nodular fasciitis. This case highlights the potential pitfalls of this lesion, especially when affecting an unusual site.

Case Presentation

A 45-year-old female with unremarkable medical history presented to the Oral Medicine Department with a slow-growing mass of the right soft palate of 6 months duration. Notably, the lesion caused deviation of her right eye (Fig. 1). Cone-beam computed tomography (CBCT) showed a large radiolucent lesion centered within and expanding the right maxillary sinus. It extended medially to the nasal septum and superiorly into the medial wall and floor of the orbit. Moreover, it had obliterated the ethmoid, frontal, and sphenoid sinuses (Fig. 2). It reached into the base of the skull and expanded the buccal and palatal maxillary cortices laterally and inferiorly. Magnetic resonance imaging (MRI) revealed a mass of measuring 55 × 35 mm in size. The lesion showed significant heterogeneous enhancement of contrast media. Although the lesion has compressed the orbital content causing proptosis; it did not invade into extraocular muscles or the globe (Fig. 2).

Fig. 1.

Clinical presentation of the lesion (intraoral and extraoral views)

Fig. 2.

a CBCT (coronal view) demonstrates an expansible lesion with destruction of right maxillary, frontal, ethmoid, and sphenoid sinuses. b T2 MRI image with heterogeneous high signal attenuation shows compression of the inferior wall of the right orbit causing compression of orbital content. c Axial view showing involvement of the right alveolar process and nasal septum by the lesion. The right nasal passage is obstructed by the lesion. d Gadolinium-enhanced, fat-suppressed MRI image (axial view) shows heterogeneous enhancement of the lesion by the contrast agent

An initial incisional biopsy was inconclusive. Re-biopsy disclosed a benign proliferation of fibroblasts without overt features of malignancy (Fig. 3). Further, the immunohistochemical examination was negative for β-catenin, BCL2, CD 68, CD 34, desmin, S-100, and SMA. It was positive for vimentin and showed a 2% proliferation index with Ki 67. A diagnosis of NF was rendered and the lesion surgically excised entirely.

Fig. 3.

a, b Histopathologic features of the maxillary mass in the first excision. Spindle cells with mild pleomorphism and hyperchromasia in fascicular arrangement. No mitotic figures or necrosis are seen in these sections. Few vessels with RBC extravasation are also noted (hematoxylin and eosin stain × 400, × 400 respectively). c Immunohistochemical staining shows low proliferative index, about 2%, with Ki-67 (× 400). d Immune positivity with CD68 (× 100) and f vimentin (× 100). e Negative staining for smooth muscle actin (× 100)

Four months later, the patient returned with a recurrent mass at the previous surgical site. Computed tomography (CT) scan revealed a lobulated soft tissue mass with enhancement, extending from skull base to the right sphenoid sinus, nasal cavity, and maxillary sinus. Enlarged cervical lymph nodes were present bilaterally, measuring up to 10 × 15 mm in size, suggesting metastatic disease. CT scan of the chest and mediastinum had no evidence of metastasis. Another biopsy of the lesion was performed and revealed a high-grade (score 3) spindle cell sarcoma with myxoid features most compatible with MFS. Mitotic activity and necrosis were observed (Fig. 4). An immunohistochemical panel showed positivity for vimentin, desmin, CK AE1/AE3, and S100; SMA, CD34, TLE1, and SOX10 were negative. Importantly, the Ki-67 index was 50%, indicative of malignancy, in contrast with previous findings.

Fig. 4.

a–d Histopathological features of the maxillary mass in the second excision. Histopathological sections show spindle cell tumor with severe degree of pleomorphism and hyperchromasia in fascicular arrangement. Abundant typical as well as atypical mitotic figures are seen. There is an extensive area of geographic necrosis is seen in this section. (hematoxylin and eosin stain × 100, × 400, × 400, × 400 respectively). e Immunohistochemical staining shows a high proliferative index, about 50% by Ki-67 (× 400). f Focal immune positivity for S-100 (× 100) and g immune negeativity for desmin (× 400)

The tumor was completely resected and the patient underwent radiation therapy. Unfortunately, the malignancy proved resistant to these measures, and the patient died three months later. Written informed consent was obtained for publication of patient information and photos for educational purposes. The ethical committee waived the requirement for review and approved case submission for publication.

Discussion

NF is a benign fibrous tumor known by numerous names including pseudotumor, pseudosarcomatous tumor, fibromyxoid tumor, fasciitis, pseudosarcomatous fibromatosis, infiltrative fasciitis, and postoperative spindle cell tumor [2]. The most common areas of occurrence are the upper extremity, trunk, and lower extremity [5]. The head and neck is an uncommon site overall, but lesions affect the buccal mucosa, upper lip, parotid gland, master muscle, and submandibular region most frequently in this region [6–9]. Nodular fasciitis is more seen in females [7]. It clinically presents as a rapidly growing, non-tender, diffuse soft tissue mass mimicking malignant mesenchymal tumors. It ranges in size from a few millimeters to a maximum of 4.7 cm in diameter.

The etiology of nodular fasciitis is unknown, but local trauma is considered to be an initiating factor in reactive myofibroblastic proliferation. Organizations of granulation tissue in the microscopic features support this theory. The term "nodular fasciitis" implies an inflammatory lesion, and it is considered as a pseudosarcomatous proliferative lesion of the soft tissue. NF is classified into subcutaneous, intramuscular, and fascia subtypes [10]. It is a nodular mass originating in the fascial connective tissue in the area around blood vessels, nerves, and muscles [11]. Clinically and microscopically, it resembles as sarcoma, but it is a benign lesion. Clinical findings of a lesion of small size, short duration, and superficial location in adults support the diagnosis of NF. Histologically, the intravascular invasion may hint to the aggressive nature of this lesion but lack of atypia and atypical mitotic figures favor its benign nature [12].

A few malignant neoplasms such as fibrosarcoma, leiomyosarcoma, and malignant peripheral nerve sheath tumor can share the similar histological features with NF. Immunohistochemistry may be a useful adjunct to discern between these entities [10]. NF is positive for vimentin, focal smooth muscle, and smooth muscle actin, but desmin, CD34, and S-100 are negative.

The treatment of choice for NF is surgical excision and recurrence is rare. Intralesional steroid therapy has been performed with a high success rate [13].

MFS is a soft-tissue sarcoma derived from fibroblastic cells. This entity rarely affects the head and neck region [14, 15]. MFS in the sinonasal tract can cause pain, swelling, paresthesia, epistaxis, nasal obstruction, rhinorrhea, occasional loosening of teeth, and ulceration of the overlying mucosa [16]. The diagnosis of MFS is not based on the clinical presentation because these findings are similarly present in other soft tissue neoplasms [16]. Malignant radiographic features such as an osteolytic lesion with ill-defined borders and local invasion may be present, but these are not diagnostic [17]. Diagnosis of MFS is based on specific histopathologic features, such as the presence of alternating hypocellular, myxoid areas, and hypercellular, fibrous areas. Pleomorphic neoplastic cells and inflammatory cells are characteristic, as are curvilinear, thin-walled blood vessels prominent in myxoid areas [15]. Immunologic staining is strongly positive for vimentin and CD-34, which indicates the tumor's fibroblastic origin. MFS is negative for S-100 and variably positive for SMA [15].

The local recurrence rate is high in MFS at 50–60%, and the risk of metastasis is approximately 20–25% [18]. Complete surgical resection with adequate resection margins of 1–3 cm is necessary for to suppresses the risk of local recurrence. The indication of adjuvant radiotherapy and chemotherapy is still unclear and is usually indicated in high-grade tumors due to risk of metastases at the time of diagnosis. Prophylactic neck dissection is also controversial.

Conclusion

Due to the overlapping clinical and microscopic features of MFS to benign and malignant tumors, thorough histopathologic examination with adjunct studies is necessary to achieve a correct diagnosis. Appropriate treatment and accurate diagnosis of MFS in the head and neck region is difficult due to its rarity and potential for misdiagnosis.

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflict of interest to disclose.

Ethical Approval

This is a case report. The Institutional Review Board has confirmed that no ethical approval is required.

Informed Consent

Patient (at the time of living) and patients’ family signed a written informed consent for using patients’ data and information’s, including photos, for scientific purposes.