Dedifferentiated liposarcoma of the oral floor: A case study and literature review of 50 cases of head and neck neoplasm

Massive low-grade myxoid liposarcoma of the floor of the mouth: A case report and review of literature

BACKGROUND

Oral liposarcoma is an extremely rare lesion that is often clinically misdiagnosed as a benign tumor due to its asymptomatic and indolent clinical course. Here, we report a case of massive low-grade myxoid liposarcoma (MLS) of the floor of the mouth.

CASE SUMMARY

A 71-year-old man presented with a huge mass in the left floor of the mouth. A biopsy was performed, and a diagnosis of a myxoid tumor suspicious for low-grade MLS or myxoma was made. Gadolinium-enhanced T1-weighted magnetic resonance imaging showed an intensely enhanced tumor lesion that occupies the left sublingual space and extends to the submandibular space. Submandibular dissection, tumor resection, and reconstruction with a radial forearm flap were performed. The surgical specimen exhibited histologically low-grade MLS. Fused in sarcoma (FUS, also known as TLS) and DNA damage-inducible transcript 3 (DDIT3, also known as CHOP) break-apart was not detected in the fluorescence in situ hybridization analysis. The tumor was completely encapsulated and did not require additional treatment. Furthermore, no recurrence was reported 40 mo after surgery.

CONCLUSION

We experienced an extremely rare, massive, low-grade MLS emerging from the floor of the mouth. Oftentimes, an MLS of the floor of the mouth lacks significant clinical findings and is often misdiagnosed. Although no FUS-DDIT3 fusion gene was detected, a low-grade MLS was ultimately diagnosed based on the histological findings.

Rare Diseases of the Oral Cavity, Neck, and Pharynx

Diseases occurring with an incidence of less than 1-10 cases per 10 000 individuals are considered as rare. Currently, between 5 000 and 8 000 rare or orphan diseases are known, every year about 250 rare diseases are newly described. Many of those pathologies concern the head and neck area. In many cases, a long time is required to diagnose an orphan disease. The lives of patients who are affected by those diseases are often determined by medical consultations and inpatient stays. Most orphan diseases are of genetic origin and cannot be cured despite medical progress. However, during the last years, the perception of and the knowledge about rare diseases has increased also due to the fact that publicly available databases have been created and self-help groups have been established which foster the autonomy of affected people. Only recently, innovative technical progress in the field of biogenetics allows individually characterizing the genetic origin of rare diseases in single patients. Based on this, it should be possible in the near future to elaborate tailored treatment concepts for patients suffering from rare diseases in the sense of translational and personalized medicine. This article deals with orphan diseases of the lip, oral cavity, pharynx, and cervical soft tissues depicting these developments. The readers will be provided with a compact overview about selected diseases of these anatomical regions. References to further information for medical staff and affected patients support deeper knowledge and lead to the current state of knowledge in this highly dynamic field.

Well-Differentiated/Dedifferentiated Liposarcoma Arising in the Upper Aerodigestive Tract: 8 Cases Mimicking Non-adipocytic Lesions

Well-differentiated (WDL) and dedifferentiated liposarcomas (DL) of the pharynx, larynx and oral cavity are rare, often mimicking benign lipomatous neoplasms or non-lipogenic mesenchymal tumors. Cases of WDL/DL arising in the upper aerodigestive tract, exclusive of the cervical esophagus, were reviewed. Morphologic features, ancillary studies, including fluorescence in situ hybridization (FISH) studies for CPM/MDM2, and clinical data was catalogued. Eight WDL/DL (4 WDL, 4 DL); were identified in patients ranging from 32 to 77 years (median 52.5 years; 6 males, 2 females) with sites of origin including hypopharynx (5 cases), larynx (2 cases) and oral cavity (1 case). Six of the 8 cases were received for expert consultation, and the remaining 2 cases were initially misdiagnosed as benign lymphangiomatous or fibroepithelial polyps. Morphologically, 4 tumors had areas mimicking various non-lipomatous soft tissue tumors including nodular fasciitis, mammary-type myofibroblastoma, low-grade myofibroblastic sarcoma and undifferentiated pleomorphic sarcoma, 2 cases simulated benign hypopharyngeal polyps, and 1 lesion was notable for a dense lymphoplasmacytic infiltrate suggestive of hematolymphoid neoplasm or IgG4-related sclerosing disease. FISH showed amplification of CPM/MDM2 (8/8 cases). All cases (4/4) with longer than 1-year of follow-up recurred (45-118 months) with 1 tumor showing progression to DL. WDL/DL presenting in the upper aerodigestive tract are rare and diagnostically challenging. Awareness of the morphologic spectrum of WDL/DL coupled with appropriate use of MDM2 FISH is essential for accurate classification and management, as these tumors appear to have a high risk for local recurrence and eventual dedifferentiation in these anatomical locations.

Hypopharyngeal Dedifferentiated Liposarcoma in the MDM2 Era: A Case Report and Short Review

Pharyngeal liposarcomas are very rare; still more rare are dedifferentiated liposarcomas in the pharynx. An 82-year-old man presented with dysphagia, voice changes, weight loss, nasal regurgitation of liquids, and coughing spells. A 3.5 cm mass was identified in the hypopharynx. The mass was biopsied and diagnosed as a benign fibroepithelial polyp. Continued symptoms and airway obstruction prompted a pharyngectomy, and the mass was then diagnosed as dedifferentiated liposarcoma. Due to infrequency and subtle histological findings, liposarcomas of the head and neck can be misdiagnosed and recur.