This paper reports a rare case of Low-grade ﬁbromyxoid sarcoma (LGFMS) that occurred primarily in the parapharyngeal space, in a 57-year-old woman. To the best of our knowledge, this is the first case of LGFMS arising from the parapharingeal space reported in the literature. Primary sarcomas of the head and neck region are very rare, accounting for approximately 1% of malignancies in this region. LGFMS is a distinctive type of soft-tissue sarcoma that was first described by Evans in 1987. LGFMS may be included in the differential diagnosis of tumors of the parapharyngeal space, and especially among the bland-looking spindle cell lesions. Despite its bland-looking morphology, this sarcoma should be recognized to avoid confusion with other bland-looking benign spindle cell lesions. Radical surgical resection with clear margins, is the treatment of choice of LGFMS. Despite its bland-looking histologic appearance, it is characterized by a malignant behavior with high rates of local recurrence and metastatic spread. For these reasones, all patients with LGFMS are recommended for long-term follow-up.
Low-grade fibromyxoid sarcoma are rare tumors.
Only one case of Low-grade fibromyxoid sarcoma is reported arising in parapharyngeal space.
Surgery of the parapharyngeal space.
Primary sarcomas of the head and neck region are very rare, accounting for approximately 1% of malignancies in this region [ , ]. Low-grade ﬁbromyxoid sarcoma (LGFMS) is a distinctive type of soft-tissue sarcoma that was first described by Evans in 1987 [ ] and subsequently by Fletcher and colleagues [ ]. Despite its bland-looking histologic appearance, it is characterized by a malignant behavior with high rates of local recurrence and metastatic spread [ ]. Due to its bland-looking morphology, it might be confused with other benign spindle cell lesions and undertreated. The age distribution in the cases reported in the literature, ranges from childwood to the eighth decade [ ]. Male and female are approximately equally affected. LGFMS primarily occurs in the soft tissues of the extremities and trunk, with only few cases reported in the head and neck region [ , , , ]. Molecularly, it is characterized by a traslocation of chromosomes 7 and 16, leading to the gene fusion product FUS/CREB3L2 [ ] or, less frequently, to FUS/CREB3L1 [ ]. However, occasional cases of LGFMS lacking FUS rearrangements have been reported [ ]. Immunohistochemical analyses, showing a diffuse and strong cytoplasmic expression of MUC4, are extremely helpful in confirming the morphological suspicion [ ]. The most striking morphologic features of LGFMS include alternating myxoid and fibrous areas, prominent curvilinear or branching/plexiform vasculature [ ] and collagen pseudorosettes [ ]. The neoplastic cells vary from spindle-to stellate-shaped cells.
We herein report a rare case of LGFMS that occurred primarily in the parapharyngeal space. To the best of our knowledge, this is the first case of LGFMS arising from the parapharingeal space reported in the literature so far.
Presentation of case
A 57-year-old woman presented with painless, slowly-expanding mass in the right side of the neck. The mass had first appeared one year before the surgical consultation. The patient denied pain, and did not exhibit any weight loss or other constitutional symptoms. The patient also denied smoking, alcohol consumption and using drugs. Physical examination revealed asymmetry of the neck, with firm and non-tender mass in the right side of the neck, measuring 8 cm × 4 cm with clear border and moderate hardness. No enlarged lymph nodules were palpated on the neck. Tongue dyskinesia and oral mucosal diseases were absent, the lateral pharyngeal wall showed no distension, and mouth opening was not limited. She was subjected to an ultrasound examination of the neck and ultrasound-guided needle biopsy. The biopsy result demonstrated a “benign chondroma”. So, a Computed tomography (CT) with and without contrast, was considered the appropriate investigation.
CT showed a large, well-circumscribed, hyperdense mass that measured approximately 8 cm × 3 cm X 4 cm, involving the right parapharyngeal space, with dislocation of the major vessels posterolaterally ( Fig. 1 , and Fig. 2 ). The mediastinal computed tomogram and electrocardiogram (EGC) were normal, and the results of routine laboratory tests were within reference ranges. A fine-needle aspiration biopsy showed rare short spindle cells without nuclear atypia and bloody background. Mitoses or necrosis were absent. The possibility of a spindle cell lesion, likely benign, was suggested, but surgical excision was mandatory for a correct diagnosis.
After the complete systematic examination, complete excision of the mass was performed with the patient under general anesthesia. The tumor was resected with a right cervical antero-lateral approach, using a vertical incision on the skin projection of the anterior margin of the sternocleidomastoid muscle. After the exposure and the lateral retraction of the muscle, the tumor was easily exposed. The mass was well circumscribed and was blunt dissected along the carotid artery and jugular vein. Post-operatively, the patient was free of symptoms and discharged on day 5 after the operation with no complications. After the final histological results, the staging was completed with a whole body PET/CT scan. In relation to stage (T2b,N0,M0,G1) and the low degree of malignancy and, characteristic of this type of neoplasm, after the consultations of the oncologist and the radiotherapist, the indication for adjuvant therapies was excluded and the patient started a strict follow-up planned with: clinical examination every 3 months for the first 2 years, associated with an neck ultrasound every 3 months for the first 2 years and a CT of the neck once a year for the first 3 years. And a whole body PET/CT scan once a year for the first 5 years. At the time of the submission of this paper, the patient has been followed 2 years after the surgery with no evidence of tumor recurrence ( Fig. 3 ). She will continue the follow-up.
The surgical specimen was submitted for histological examination in neutral-buffered 10% formalin, dehydrated using standard techniques, embedded in paraffin, cut to 5 μm, and stained with hematoxylin and eosin (H&E). Gross examination showed a well-circumscribed, nodular mass, measuring 8cm in greatest diameter. The cut surface showed a homogeneous mass, firm in consistency and whitish in color. Histological examination showed clear margins. The tumor appeared as a well circumscribed fibro-myxoid mass ( Fig. 4 A). Notably fibrous areas were alternating with myxoid areas ( Fig. 4 B). Tumor was composed of bland-looking spindle cells arranged into short intersecting fascicles ( Fig. 4 C). Tumor vasculature was represented by capillary-like blood vessels with branching or curvilinear configuration ( Fig. 4 D). A striking feature was the presence of variably-sized pseudorosettes composed of hyalinized collagen surrounded by a palisade of neoplastic cells ( Fig. 4 E). Immunohistochemistry, performed with the labeled streptavidin–biotin peroxidase detection system, revealed diffuse expression of vimentin and MUC4 ( Fig. 4 F), and focally of EMA. No immunostaining was obtained with the following antibodies: α-actin, desmin, myogenin, CD34, pancytokeratins, S100 protein, GFAP, p63, STAT6. Based on morphological and immunohistochemical features, the diagnosis of “ low-grade fibromyxoid sarcoma ” was rendered.