Introduction

Low-grade fibromyxoid sarcoma (LGFMS) is a variant of fibrosarcoma that usually occurs in the deep soft tissues of the extremities in young or middle-aged adults [1]. Primary sarcomas of the head and neck region are very rare and constitute approximately 1% of malignancies in this region [2]. Although LGFMS acts like a benign tumor with a slow growth pattern, it has very high potential for local recurrence and distant metastasis [3]. The incidence of LGFMS is very similar between men and women, and it is a tumor that can be seen at all ages [4, 5]. LGFMS is primarily seen in the deep soft tissues of the extremities and trunk, and a small number of cases have been reported in the head and neck region [3, 4]. It is genetically characterized by translocation on chromosomes 7 and 16 [6]. Immunohistochemically, most cells of this sarcoma are strongly positive for vimentin but are generally negative for α-actin, desmin, S-100 protein, cytokeratin, CD34, and CD56 [7]. LGFMS typically appears as a well-circumscribed, encapsulated mass without necrosis or bleeding foci [8]. We aimed to obtain a more accurate idea of LGFMS by reviewing the literature and examining relapse, recurrence, gender and affected areas in cases reported to date. As a result of this detailed literature review, we summarized the data obtained in a table, which constitutes the most comprehensive list of LGFMS cases with the head and neck localization in the literature (Table 1).

Case

A 56-year-old male patient presented to our clinic with a painless swelling growing slowly in the right malar region. On his physical examination, there was a swelling extending to the right upper hard palate. The endoscopic examination revealed a soft tissue mass filling the middle meatus in the right nasal passage. The nasopharynx was natural, and all routine blood tests were normal. Contrast-enhanced paranasal sinus, neck and thorax tomographies were taken. Diagnostic imaging revealed a contrast-enhancing soft tissue mass in the right maxillary sinus, which had eroded the bone structures of the sinus. The mass extended into the right nasal passage and filled the middle meatus (Figs. 1, 2). However, no signs of invasion or metastasis were detected. A punch biopsy was performed from the part of the mass extending to the nasal passage under local anesthesia. Histologically, the mass was characterized by epithelioid cells with a fibrotic basis. In the immunohistochemical examination, vimentin and MUC4 were positive while S100, CD34, desmin, actin, keratin, and epithelial membrane antigens (AE1/AE3, LMWK, and HMWK) were negative. Thus, we planned the excision of the entire tumor, including the surrounding soft tissue, under general anesthesia. We made a Weber-Ferguson incision to reach the tumor (Fig. 3). After flap elevation, it was observed that the maxillary anterior wall bone structure was completely lost. The tumor was seen to have expanded into surrounding tissues (Fig. 4). The tumor was macroscopically removed en-block (Figs. 5, 6). The pathological examination revealed tumor cells growing in nests surrounded by partially spindle-like cells and partially myxoid stroma. Some atypical mitotic figures were also seen (Figs. 7, 8). Immunohistochemically, vimentin was positive in tumor cells, but actin, CD31, CD34, S100, and desmin were negative. The Ki-67 proliferation index was 10–20%. The fluorescent in situ hybridization test was positive for FUS gene rearrangement. Thus, the patient was diagnosed with LGFMS. Radiotherapy was initiated from the third week after surgery. At the end of the postoperative third month, the follow-up computed tomography showed that the tumor had filled the maxillary sinus again and reached its initial size (Figs. 9, 10).

Fig. 1
figure 1

Preoperative computed tomography image in the coronal plane

Full size image
Fig. 2
figure 2

Preoperative computed tomography image in the axial plane

Full size image
Fig. 3
figure 3

Weber-Ferguson incision

Full size image
Fig. 4
figure 4

Appearance of the mass after flap elevation revealing the defect on the anterior wall of the maxilla

Full size image
Fig. 5
figure 5

Macroscopic image of the mass that was removed en-block together with the part extending into the nasal passage

Full size image
Fig. 6
figure 6

A Foley catheter inserted in the sinus cavity and inflated to 15 cc sf after the removal of the mass in order to provide support for the eroded maxillary sinus bone structure during healing and prevent cosmetic deformity

Full size image
Fig. 7
figure 7

Low cell rate and dense vascular network tumor morphology in diffuse myxoid focal collagenized stroma (H & E × 100)

Full size image
Fig. 8
figure 8

Spindle cells with mild pleomorphic nuclei in fibromyxoid stroma (H & E × 200). The pathology revealed tumor-cells growing in nests surrounded by partially spindle-like cells and partially myxoid stroma. Some cells were eosinophilic and others showed clear cell-like cytoplasm. Many mitoses were observed with some atypical mitotic figures

Full size image
Fig. 9
figure 9

Postoperative third-month follow-up computed tomography image in the coronal plane

Full size image
Fig. 10
figure 10

Postoperative third-month follow-up computed tomography image in the axial plane

Full size image
Table 1 List of all case reports obtained after a comprehensive review of the literature (PubMed and Google Scholar)
Full size table

Discussion

LGFMS is a benign tumor rarely seen in the head and neck region. Despite acting like a benign tumor with a slow course, it can exhibit malignant behaviors such as distant metastasis and local recurrence [8]. In the head and neck region, the maxillary sinus localization of LGFMS is even rarer, and our literature review revealed only five reported cases in total [1, 9,10,11]. Although there are many case reports or series about LGFMS in the literature, LGFMS continues to be a challenging and complex clinical entity for surgeons. Since it was first described by Evans in 1987, confusions remain concerning the diagnosis and treatment of LGFMS [12]. Based on our own clinical experience, we can state that unfortunately, it is very difficult to diagnose these patients in centers that are not equipped with molecular, genetic and immunohistochemical laboratories. Even in most experienced clinics, fine needle aspiration biopsy (FNAB), which is the first procedure used for a pathological evaluation in head and neck masses, is insufficient in diagnosing this tumor [13]. In a neck mass that cannot be diagnosed with FNAB, if there is no necrosis or hemorrhage in the mass due to radiological invasion, metastasis or high mitosis, it naturally becomes difficult to make a radical surgery decision. Even if a radical surgery decision is taken, this does not necessarily improve the condition of the patient or the course of the disease. Nevertheless, the radical surgical approach maintains its exaggerated popularity as a treatment method recommended by many surgeons and considered to be the most beneficial for the patient [1, 2, 10, 13,14,15]. The surgical treatment of LGFMS, which also occurs in the extremities in addition the head and neck region, does not affect the comfort of the patient as dramatically as the large resection of a tumor in the maxillary sinus. Unfortunately, the large surgical excision of LGFMS in the head and neck region, especially in the maxilla, which has been previously described in a few cases in the literature, creates hesitations in the surgical approach due to the possibility of resulting in serious cosmetic deformities [11, 13]. Cosmetic concerns clearly should not change the treatment algorithm of this malignant tumor; however, the literature contains controversial discussions concerning the benefits of radical surgery, with patients often experiencing frequent and short-term recurrences and distant metastases and requiring multiple operations [3, 4, 16, 17]. In the first and longest-term follow-up study, LGFMS was detected in the head and neck region in two patients, one aged 26 and the other nine years, requiring nine and seven operations, respectively after the first excision of LGFMS [3]. Distant metastasis developed in the nine-year-old patient despite radiotherapy application after the last recurrent tumor excision, and the 42-year-old patient died due to distant metastasis after repeated metastasis operations (six operations).

According to Ewans, the mean recurrence time of LGFMS is 3.5 years, while the average duration of distant metastasis is five years. However, such long-term follow-ups are very limited in the literature. In this respect, the literature can be considered insufficient in terms of revealing the true recurrence, distant metastasis capacity and progression rate of the disease. On the other hand, recurrence after surgery is not the only problem caused by the genetic and histological features of LGFMS. Another factor that makes treatment difficult is the low mitosis rate, which is one of the most characteristic features of the tumor [8, 18]. The low mitotic rate and fibrotic background also limit the effectiveness of radiotherapy and chemotherapy, which are highly effective in malignant tumors [19, 20]. This situation leads to the inability to prevent recurrence associated with residual tumor at microscopic level after surgery. As we mentioned in the case we presented, although we were sure of the surgical margins and started radiotherapy immediately after surgery, our patients relapsing in a very short time presented serious evidence for that it is a difficult disease to treat.

Lastly, during the literature review on LGFMS conducted as part of this study, we found 36 cases for which gender and age information was available, and they had a wide age range from two months to 84 years, with the mean value being 38.6 years, which is consistent with previous reviews [4, 15]. However, based on the gender data of 36 patients, among the patients with head and neck involvement, LGFMS was 2.6 times more common in males. In the literature, equal or similar prevalence is generally reported for both genders [4, 5, 15].

In conclusion, LGFMS is a soft tissue tumor that should be diagnosed genetically and immunohistochemically. The benefit of FNAB in diagnosis is very limited. The best option for its treatment is radical surgical excision, although it does not provide a desired satisfaction level in today’s conditions. Although the effects of radiotherapy and chemotherapy remain controversial in the literature, we know that radiotherapy was not beneficial for our patient. We consider that all scientific discussions concerning this issue should continue, and further diagnosis and treatment studies should be conducted on LGFMS.